spectre6000
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Posts posted by spectre6000
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Raw. I'm not expressly after the polymer finish. I'm hoping to see it be one of those things that improves over time and with use and upkeep. See time stamps for approximate times. Aside from suggesting you use Chrome, I don't know what's up with the pictures. I posted them shortly after the forum switched to the new format, and made sure at the time they were displaying properly in Chrome, Firefox, and Safari (please never ever use IE -the internet). Now, however, I'm only seeing them in Chrome. It's been too long to go back and edit them, so I really don't know what to tell you... That's really annoying... I put a lot of work into that.
Outside of the raw oil testing, it's being used in conjunction with a blend of oils and waxes that I'm working with in an attempt to create an especially spectacular oil finishing system. Results so far have been better than anticipated. All that research and experimentation gave me a tremendous amount of insight into the roles the oils play in leather modification and preservation, and the effects they have on color, flexibility, smell, feel, etc. What's the most interesting is the analysis of the byproducts of oil decomposition in leather, and the associated effects on the same. Time is still a factor I have yet to be able to account for fully due to lack of said time machine, but based on historical uses and analysis I am more than confident in the long term viability. The question is simply one of how much better things will get!
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Sure. It's all laid out in the Chemistry thread, but here's the short take:
Historical: Linseed oil (aka flax oil) is what was used to make patent leather back before it was plastic garbage. Boiled (to accelerate breakdown of the triglyceride into the polymerizing free fatty acids) and combined with carbon black and Prussian blue (pigments), it was applied in many coats over many days, then polished to a high shine resulting in a "black, flexible, and durable leather with a high sheen".
Chemical: Linoleic acid is just the name for a fatty acid (not an acid in the battery acid/Batman's Joker/Wicked Witch of the West sense, just that the pH is <7) with a specific number of carbon atoms (18 in this case) and two double bonds. These fatty acids are arranged on a glycerine backbone called a triglyceride (oil in this case). The two double bonds are places on the molecule that are susceptible to bonding preferably with oxygen. When they bond with oxygen, the molecule breaks apart into (a diglyceride and) a free fatty acid. This breaking/bonding with oxygen is what is commonly called 'going rancid', but 'rancid' in the common sense typically refers to a specific smell; that smell is a particular aromatic compound or group of compoinds. In the case of linseed/flax oil though, the byproduct of this reaction is a free fatty acid that dries and polymerizes into a plastic like substance that is flexible and durable (see historical reference).
Coincidentally, the primary fatty acid present in neat/neetsfoot oil is oleic acid, which has the same number of carbon bonds, but one fewer double bond. Since it only has one (and the location of it), it's less likely to decompose and the byproduct is different. I'm pretty sure it's an aromatic compound that actually smells 'rancid'.
All (non-petroleum) oils are just naturally occurring combinations of triglycerides with varying numbers of carbon bonds and varying numbers of double bonds in various locations and orientations. They all break down, or go rancid (neat/neetsfoot oil is not magical in this way). The byproducts of decomposition can smell bad ('rancid'), smell good (leather, vanilla, spice, etc.), or not smell at all (polymer).
In my own experiments in treating vegetable tanned leathers with various oils and combinations of oils in various percentages, stages, etc. my findings from linseed/flax oil are summarized as follows:
- Initial smell is probably the best leather smell. It smells characteristically of leather, but sweet. Very pleasant. This is the only oil save walnut (a hint of earthy spiciness) that has any notes on smell. The smell dissipates after a day or two and is no longer distinguishable.
- Color is average.
- Flexibility is average.
- Dispersion is average. I applied the oil to one half of the sample (demarcated with painters tape), and observed natural distribution over time.
- Sheen is average initially, but seems to be increasing with time. Same with walnut (similar fatty acid composition). Where the oil has been applied is slightly shinier than where it hasn't. This effect should increase over time and with additional applications.
Methodology: I took several 3"X4" scraps of vegetable tanned leather and applied various oils as usual to one half of the sample. Add time and observe. See the chemistry thread for photos, and lots of extra detail.
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I just posted an update in my chemistry thread. It's dense, but I was essentially after the same thing when I started the project. Current iteration (not detailed in the thread, but maybe later) is natural, organic (where possible), plant derived (gluten free, Atkins friendly, kosher, and halal, lol), and looks/feels amazing. Linseed oil is addressed specifically, and has played a starring role in some of my more recent leather treatment fiddlings (hint: I disagree with Martyn on chemical and historical grounds).
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An update on this for the one or two people still following this little vanity project...:
I unpacked the treated samples detailed above after moving recently, and discovered the fatty acid composition of the beeswax must have some shorter carbon chains than I initially thought, or ultra long carbon chains in the wax are not as stable as I thought and are also subject to the sort of precipitates that result in spue/spew. The heavier (50% and greater) beeswax concentrations are all showing spue/spew, with the higher concentrations exhibiting more noticeable effects. These samples have not been handled hardly at all, and I'm sure regular use would rub the spue/spew away pretty handily such that it would never be noticeable.
Meanwhile, I've also been experimenting heavily with oil treatments in various combinations, orders, methods, etc. I think I've landed on some pretty stellar results! There's a time aspect that I can't really control for due to lack of the proper equipment (time machines are expensive), but I am extremely confident in the long term viability of my methods. Looks and feels fantastic too! I'm still working on what I hope will be the final incarnation for regular use, but my wife is very excited for the belt she's getting out of the current iteration of this little exercise (I got tired of all the squares of belly scraps)!
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Part two of experiment execution:
A little over 24 hours has passed. The smell of the oils had more or less disappeared. The canola oil is still slightly darker than the other oils, but the colors have pretty much evened out save the heavier wax mixtures. I inspected the back of the patches, and noticed a pretty interesting trend: the lighter oils, especially the canola oil, had penetrated through to the back of the patches. This was unexpected, but not at all surprising. The implications have potential import in the next phase. I reapplied the oils for a second round. I'll probably do three total and call it good on this set.
In preparation for the next phase, I purchased a floral, pleasant smelling blend of essential oils. Rose oil was completely unavailable, and would have been insanely expensive at any rate. I don't recall the exact blend, and I haven't done any research on the makeup of the oil combination, but I don't think it's of special import. This morning over breakfast, I went back and re-read the thread and realized I forgot a step; I neglected to case the leather ahead of time, and this combined with the especially dry nature of the leather means less and less even penetration. The idea with the essential oils is to see if I can impart some especially pleasant smell to the leather. Given the loss of smell of the other oils over as little as 24 hours, I doubt very much it will, but it's in the plan and why not. I'm hoping to emulsify the essential oils into some water, and use that to case the leather. Ideally this should distribute the oils pretty evenly throughout the leather, but only in very small quantities. Again, not expecting much, but that's the plan. From there, I find the penetration of the lighter oils interesting and potentially useful. I think some stratification in the choice of oils applied in stages could have an overall positive effect. More on this later.
Finally, I was thinking about the wax mixtures. I was thinking it might be nice to use some wax to set the tooling and provide a little extra crispness and staying power. The downside to this is that it stiffens the piece overall, and could have a negative effect on longevity. The other side of the coin is that it seals the leather, and can potentially be used to shine it up a bit. Combined with some lighter fatty acid byproducts, it could result in a really nice finish over time. These two goals are pretty much counter indicated though, and I'm thinking the latter has more merit overall. It further dawned on me that the oil lowers the melting point of the wax (duh!), and I hadn't accounted for that in any way. In the event the wax/oil mixture is used for something clothing oriented (like a belt), the wearer's body heat would completely nullify the fixative properties of the wax. The 15% wax mixture is so soft at room temperature, that there's no fixing whatsoever, and I'm not sure it would have any benefit outside of sealing out moisture; this could also seal out future oilings. The 25% mixture is fairly stiff at room temperature, but held in my hand for a few minutes resulted in it turning to a consistency very much like the 15% mixture at room temperature. This could be a good middle ground for non-wearable tooled leather pieces to set the tooling a bit without it being too difficult or detrimental. The 50% mixture softened up a bit as well, but not quite as much. When suspended in the leather, this could be the golden ticket for fixing tooling with the application technique I used. The downside is that it's somewhat difficult to apply evenly, but I would say it can probably be done successfully. I'll have to mess with that one a little more. 75% wax was hard as hard can be no matter what.
At any rate, more experimentation is scheduled. Still refining the strategy. It's going to be a long time before anything conclusive can be decided in terms of whether or not any of this has results that are in any way superior or even different from the status quo, but it's a lot of fun exploring it!
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Sorry for the extended silent period. Life got busy, then I got in a pretty horrific car accident. I'm finally back to where I can get back in the shop a bit, so back to this project!
Am I correct that there have been some changes while I was away? Signing in with Facebook, and... attach images via URL?
Since we're posting photos and to get everything in the same place, here's the beeswax rendering photos:
There was more rendering after this photo, but what I have.
Soooo.... I started by cutting some belly trimmings into rectangular pieces.
Tinker Tailor for the win! I fine tuned my iron to 145° with the IR gun, used a small anvil as a thermal battery, and parchment paper to avoid ruining the iron or the anvil. The target was between 145° and 155°, erring on the low side for safety. As previously stated, that narrow range is pretty much it where the wax will be liquid and the leather won't be ruined.
I shaved the beeswax block so that I could weigh out the wax for melting.
And I weighed samples out for a total of 20 grams each (a little less than 3/4 ounce) between the wax and oil. I went with olive oil since it's the closest I have to neatsfoot (the status quo) by fatty acid content.
The five samples were neat beeswax, 75/25, 50/50, 25/50, and 15/85 beeswax to oil ratios. The partial sticky notes (somehow I only had one sticky note and the backing pad...) are marked 20, 15, 10, and 5, referring to the grams of beeswax with the unlabeled being 3. The balance was filled with olive oil to a total of 20 grams. Then...
A last minute sanity check, and...
Into the double boiler. This is the smaller of the two pots I bought for this experiment with an aluminum pie tin sliced to form a smaller diameter, perforated, and wrapped in foil so it would stay together under the weight of the glass sample vessels. I think they were glass tea light candle holders, and I got them at the same thrift store I got all the hardware for this experiment. I also found this:
February 1958 Brother portable sewing machine in pretty good, albeit neglected condition. I restored it for my wife for Xmas, and she loved it! Great little thrift store.
Anyway...
The bellies were pretty seriously old... So much so that I have no idea when I got them, from where, or why. They're all slightly different colors, and all pretty dry, so I taped them off to have a bit more control over the control. Then I got to business.
While the wax/oil mixtures were melting, I made go with the oils. The flax oil smells sweet, walnut smells earthy, canola doesn't have much in the way of a smell, and the olive oil smells spicy. I applied multiple coats until it took a little longer for the oil to all be absorbed, and heated the wax-based samples to temp prior to applying the wax oil mixture. This allowed the wax to absorb and not just harden at the surface on contact. I dipped the hot neat wax sample into the hot wax at one end just to see how stiff it got.
Here's the end result for the day:
Left to right, top to bottom, that's canola oil, 25% wax, 100% wax, flax, 15% wax, 75% wax, walnut, olive, and 50% wax, and the loner is the control (the organization makes more sense if you rotate it to the right 90°, where you get the waxes in decreasing order followed by the oils with the control to the side). It should be noted that the leather was very dry, and the tape pulled some of the top grain off, lightening the appearance.
The higher wax concentration samples proved difficult to apply, and the result appears pretty splotchy. Application with a good aesthetic result would be either difficult or very time consuming and complicated without significant investment in equipment or risking ruining the leather via heat. Additionally, given the role of the oil in the leather, I don't think ultra high beeswax mixtures will allow the fatty acids to do their lubrication and migration song and dance. That said, it seems the heavier wax mixtures would have a fixative effect on any tooling, and this is desirable... On the other end of the spectrum, it's simply too soon to have any idea how the polymerization of the shorter fatty acid chains will affect the end result.
In terms of color, there are variations in the leather sample pieces muddying things up a bit, but all methods and materials darkened the leather considerably at this point with canola as the surprise stand out. I'm not sure why this is. On the neat wax sample, you can see a strip at the end where I heated it up and just dunked it into the hot wax. The heavy saturation reflects less light than the less saturated area. The splotchiness in the 75% wax sample is a prime example of the difficulty applying higher wax concentrations, while the lesser wax mixtures were considerably easier. Time will tell how these effects last over time.
In addition to the application experience, another significant subjective observation is the smell. The walnut oil sample smelled predominantly of walnut; earthy and not unpleasant, but not especially pleasant either. The olive oil sample smelled essentially like olive oil with no real leather aroma; a bit on the spicy side. The canola oil had no real smell at all. The waxed samples smell to varying degrees of sweet honey to spicy olive oil based on their respective concentrations without much leather smell. The flax oil is sweet on its own, and in the leather has a wonderful smell that stands out above the rest. The leather by itself didn't smell especially strong of anything (it's old), but the flax oil made for a very good leather smell beyond expectation. I don't know why this is, but based on reports of fish oils smelling especially like leather, it makes me wonder exactly what's going on there. They both are notoriously high in omega 3 fatty acids (mid-length polyunsaturated), so maybe there's something going on there... Who knows.
Finally, I allowed the wax mixtures to cool and harden. I expected the neat wax to harden like the rest of the wax, and that the lesser samples would soften considerably to the point that the 15% sample would barely be any more viscous than the oil, but surprisingly they all hardened save the 15% sample.
I stuck my finger in each one, and while the 25% sample gave a tiny bit where some bubbles had formed but was otherwise solid, only the 15% mixture really gave at all. Some water had splashed in from the boiling water, and it squished out from this sample as well. As an aside, it makes good lip balm. Some fiddling with other oils could make for a pretty awesome home made Burt's Bees replacement (the olive oil just lacks the good smell)!
So... Where does that leave us? The 15%, 25%, and to a lesser extent 50% wax mixtures were easy enough to apply as to be viable. Heavier than that was too difficult using these methods. The liquid oils are obviously easy to apply, but time will tell how they do over time. I like the idea of the wax fixing tooling, but have some concern at what it will do over time as the oils break down and subsequently migrate... Or would the wax prevent migration? Additionally, wax is known to stiffen leather, but with enough oil it softens considerably... The question is how this affects things when it's suspended between the leather fibers. How does it affect things as the oil breaks down? The same question can be asked of the polymerization from the shorter fatty acid chains oxidizing. Does this form a barrier that makes subsequent applications of oil difficult or even impossible? The smooth surface that results from the polymer film would make for a good dark color, this would be even more the case when combined with a percentage of wax. The sweet smell of the wax combined with the sweet leather smell from the flax oil and the shine and tooling fixation could be awesome! It could also ultimately shorten the lifespan of the work... It would probably be years before the effects were noticeable, and they may not happen at all, but it is something outside the norm about which I can't find any information.
The next phase is to wait and see what happens over time... Months... Years... I'm not that patient for the immediate projects, so I'll have to decide on something sooner. The next thing I'd like to try is some lighter wax mixtures with other oils. The flax is especially interesting from the perspective of the eventual high gloss polymer finish and dark color it would ultimately result in, but I want to get some longer carbon chains in there too for a bit better lubricity over a longer period of time. That might ultimately mean a multi-phase finish. Maybe a light oiling or two front and back with olive oil, then finish with a heavy application of a 15-25% beeswax/flax oil mixture. That would help the tooling stay crisp, eventually result in a very polished finish, and the sweet smell of the wax and the sweet leather smell will likely be a pretty killer combo. I might investigate another oil or two in there for fun too when I go for the second round... We'll see.
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OK. I think I figured it out. I can't go back and edit the previous post, but I'll repost it with the photos correctly linked. I think it was my fault. Stand by.
Maybe a mod can do some mod magicks and delete the dupe, move things around, or whatever else makes sense.
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Sorry for the extended silent period. Life got busy, then I got in a pretty horrific car accident. I'm finally back to where I can get back in the shop a bit, so back to this project!
Am I correct that there have been some changes while I was away? Signing in with Facebook, and... attach images via URL?
Since we're posting photos and to get everything in the same place, here's the beeswax rendering photos:
There was more rendering after this photo, but what I have.
Soooo.... I started by cutting some belly trimmings into rectangular pieces.
Tinker Tailor for the win! I fine tuned my iron to 145° with the IR gun, used a small anvil as a thermal battery, and parchment paper to avoid ruining the iron or the anvil. The target was between 145° and 155°, erring on the low side for safety. As previously stated, that narrow range is pretty much it where the wax will be liquid and the leather won't be ruined.
I shaved the beeswax block so that I could weigh out the wax for melting.
And I weighed samples out for a total of 20 grams each (a little less than 3/4 ounce) between the wax and oil. I went with olive oil since it's the closest I have to neatsfoot (the status quo) by fatty acid content.
The five samples were neat beeswax, 75/25, 50/50, 25/50, and 15/85 beeswax to oil ratios. The partial sticky notes (somehow I only had one sticky note and the backing pad...) are marked 20, 15, 10, and 5, referring to the grams of beeswax with the unlabeled being 3. The balance was filled with olive oil to a total of 20 grams. Then...
A last minute sanity check, and...
Into the double boiler. This is the smaller of the two pots I bought for this experiment with an aluminum pie tin sliced to form a smaller diameter, perforated, and wrapped in foil so it would stay together under the weight of the glass sample vessels. I think they were glass tea light candle holders, and I got them at the same thrift store I got all the hardware for this experiment. I also found this:
February 1958 Brother portable sewing machine in pretty good, albeit neglected condition. I restored it for my wife for Xmas, and she loved it! Great little thrift store.
Anyway...
The bellies were pretty seriously old... So much so that I have no idea when I got them, from where, or why. They're all slightly different colors, and all pretty dry, so I taped them off to have a bit more control over the control. Then I got to business.
While the wax/oil mixtures were melting, I made go with the oils. The flax oil smells sweet, walnut smells earthy, canola doesn't have much in the way of a smell, and the olive oil smells spicy. I applied multiple coats until it took a little longer for the oil to all be absorbed, and heated the wax-based samples to temp prior to applying the wax oil mixture. This allowed the wax to absorb and not just harden at the surface on contact. I dipped the hot neat wax sample into the hot wax at one end just to see how stiff it got.
Here's the end result for the day:
Left to right, top to bottom, that's canola oil, 25% wax, 100% wax, flax, 15% wax, 75% wax, walnut, olive, and 50% wax, and the loner is the control (the organization makes more sense if you rotate it to the right 90°, where you get the waxes in decreasing order followed by the oils with the control to the side). It should be noted that the leather was very dry, and the tape pulled some of the top grain off, lightening the appearance.
The higher wax concentration samples proved difficult to apply, and the result appears pretty splotchy. Application with a good aesthetic result would be either difficult or very time consuming and complicated without significant investment in equipment or risking ruining the leather via heat. Additionally, given the role of the oil in the leather, I don't think ultra high beeswax mixtures will allow the fatty acids to do their lubrication and migration song and dance. That said, it seems the heavier wax mixtures would have a fixative effect on any tooling, and this is desirable... On the other end of the spectrum, it's simply too soon to have any idea how the polymerization of the shorter fatty acid chains will affect the end result.
In terms of color, there are variations in the leather sample pieces muddying things up a bit, but all methods and materials darkened the leather considerably at this point with canola as the surprise stand out. I'm not sure why this is. On the neat wax sample, you can see a strip at the end where I heated it up and just dunked it into the hot wax. The heavy saturation reflects less light than the less saturated area. The splotchiness in the 75% wax sample is a prime example of the difficulty applying higher wax concentrations, while the lesser wax mixtures were considerably easier. Time will tell how these effects last over time.
In addition to the application experience, another significant subjective observation is the smell. The walnut oil sample smelled predominantly of walnut; earthy and not unpleasant, but not especially pleasant either. The olive oil sample smelled essentially like olive oil with no real leather aroma; a bit on the spicy side. The canola oil had no real smell at all. The waxed samples smell to varying degrees of sweet honey to spicy olive oil based on their respective concentrations without much leather smell. The flax oil is sweet on its own, and in the leather has a wonderful smell that stands out above the rest. The leather by itself didn't smell especially strong of anything (it's old), but the flax oil made for a very good leather smell beyond expectation. I don't know why this is, but based on reports of fish oils smelling especially like leather, it makes me wonder exactly what's going on there. They both are notoriously high in omega 3 fatty acids (mid-length polyunsaturated), so maybe there's something going on there... Who knows.
Finally, I allowed the wax mixtures to cool and harden. I expected the neat wax to harden like the rest of the wax, and that the lesser samples would soften considerably to the point that the 15% sample would barely be any more viscous than the oil, but surprisingly they all hardened save the 15% sample.
I stuck my finger in each one, and while the 25% sample gave a tiny bit where some bubbles had formed but was otherwise solid, only the 15% mixture really gave at all. Some water had splashed in from the boiling water, and it squished out from this sample as well. As an aside, it makes good lip balm. Some fiddling with other oils could make for a pretty awesome home made Burt's Bees replacement (the olive oil just lacks the good smell)!
So... Where does that leave us? The 15%, 25%, and to a lesser extent 50% wax mixtures were easy enough to apply as to be viable. Heavier than that was too difficult using these methods. The liquid oils are obviously easy to apply, but time will tell how they do over time. I like the idea of the wax fixing tooling, but have some concern at what it will do over time as the oils break down and subsequently migrate... Or would the wax prevent migration? Additionally, wax is known to stiffen leather, but with enough oil it softens considerably... The question is how this affects things when it's suspended between the leather fibers. How does it affect things as the oil breaks down? The same question can be asked of the polymerization from the shorter fatty acid chains oxidizing. Does this form a barrier that makes subsequent applications of oil difficult or even impossible? The smooth surface that results from the polymer film would make for a good dark color, this would be even more the case when combined with a percentage of wax. The sweet smell of the wax combined with the sweet leather smell from the flax oil and the shine and tooling fixation could be awesome! It could also ultimately shorten the lifespan of the work... It would probably be years before the effects were noticeable, and they may not happen at all, but it is something outside the norm about which I can't find any information.
The next phase is to wait and see what happens over time... Months... Years... I'm not that patient for the immediate projects, so I'll have to decide on something sooner. The next thing I'd like to try is some lighter wax mixtures with other oils. The flax is especially interesting from the perspective of the eventual high gloss polymer finish and dark color it would ultimately result in, but I want to get some longer carbon chains in there too for a bit better lubricity over a longer period of time. That might ultimately mean a multi-phase finish. Maybe a light oiling or two front and back with olive oil, then finish with a heavy application of a 15-25% beeswax/flax oil mixture. That would help the tooling stay crisp, eventually result in a very polished finish, and the sweet smell of the wax and the sweet leather smell will likely be a pretty killer combo. I might investigate another oil or two in there for fun too when I go for the second round... We'll see.
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It's not a question of how to get photos on here (I'm a software engineer by trade), it's a matter of I don't want to upload them to the forum servers. They're uploaded in a pretty solid and secure location, they should be able to be served from there without unnecessarily restrictive permission settings at the forum admin level. Meanwhile, I'll proceed without photos unless and until something happens there.
This project hasn't died, I start a new job Monday and I've been scrambling to wrap up the current contract between dealing with a finicky client and trying to subcontract an element of it and get that handled and done before I get completely bogged down with the new gig. Additionally, I tend to have a half dozen or so fairly significant projects going on at any one time, so sometimes balls hang in the air a little longer than I'd like. Balls sitting on the table in front of me as I type this include the leather treatment project, a sewing machine restoration project, an automotive fabrication project, a computer hardware project for the new job, and I have an aspiring luthier coming over this afternoon to pick up an acoustic top set I'm gifting him... And that's just the living room coffee table!
Meanwhile, I've been noodling on exactly what and how to divvy up the beeswax and experimental samples. I think the most likely success for my current goals is going to be an olive oil beeswax blend, but I still want to see how raw flax and walnut oils do in terms of the polymerized film on the surface of the leather for another project down the road. I only have a skosh over a pound of beeswax, and I want to be absolutely sure I have a sufficient quantity for the immediate project (locally sourced beeswax that I personally filtered, etc. would just be icing on the cake!), so if I limit the quantity used per sample to an ounce (I'm going to do everything by weight), which may honestly be a bit too generous anyway, and I want to do 25/50/75 percent blends of wax to oil, that pretty much leaves me with about zero (assuming a certain amount of process waste) for the actual project... No bueno. So I think I want to limit the wax blend samples to just that subset of oils (olive) I think will have positive results.
That's pretty much where this project stands. I'm one piece of carved mahogany away from completing one competing project, about two evenings worth of leather carving away from completing another competing project, and that's about the only real competition for this one. I picked up some small glass vessels at the thrift store yesterday (I think they were tea candle glass holder things), and I need to clean them up. I also need to figure out exactly how to suspend them in a pot for double boiling purposes... I'm thinking an aluminum pie tin... The step after that is to distribute the wax into the vessels and get everything blended, then it's time to apply finishes and finally see what's up.
Meanwhile, I need to get back to reviewing this new code base before Monday morning...
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Current status:
Waylaid by the more or less unanticipated beeswax refining project, and while I was at the thrift store picking up some sacrificial cookware, I found a beautiful sewing machine from 1959 in my wife's favorite color in a '50s Chevy Bel Air-esque design motif complete down to the owners manual, and functional but dirty and in dire need of a tune up. For $20, it was hard not to do it. So while beeswax has been melting, filtering, floating, and cooling these last several evenings, I've been methodically cleaning, lubricating, and adjusting this little jewel to like new (minus a few characterful chips in the lacquer here and there). I still need to find some foot pad things, make a few soft parts, fabricate a replacement for the one broken part, and clean the case, but the hard part is done.
Meanwhile, we went out to dinner last night with my researcher friends, and the physicist and I devised a test methodology. Using TinkerTailor's iron suggestion, today I'll go cut a few scabs of 1/4" mild steel to serve as thermal batteries to keep the temperature constant while the iron cycles. The scabs will be heated to temp on parchment paper over an iron on the appropriate setting (measured with IR thermometer) under a cotton cloth/insulator, and the leather test pieces will be placed between them to be brought up to temp. Wax/oil mixtures will be mixed ahead of time in 25%/50%/75% wax/oil ratios by weight for each test oil plus one sample for neat beeswax for a total of 13. The mixtures will be poured or placed (depending on how I feel they will be best applied, open to suggestions here), and the scabs replaced to keep the leather at the appropriate temperature while the oil/wax mixture penetrates. I'll have to play the saturation by ear unless anyone has any suggestions.
Meanwhile, the net wax yield was 481g/17 ounces/1 lb. 1 oz. of clean, spotless, sunflower yellow, honey scented beeswax. I'd love to post pictures, but this forum seems to have a white list strategy for photo hosting, and google photos is not on it somehow... Who would I have to talk to to get that rectified?
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For the wax I found an old plastic tupperware thing that I'm pretty sure the lid has disappeared its lid, lined that in parchment paper, and then lined that with a layer of aluminum foil... Wasn't enough to keep the wax from finding its way to the tupperware. I picked up a pot and lid that looked like it might be about the right size from the thrift store (and a beautiful sewing machine ca. 1959 for my wife for xmas! Because I need more projects!), cleaned it as well as I could, and used it as the top of a double boiler.
Eventually, it double boiled its way down and I ran it through some cheese cloth. It's cooling now on the stove, and it's definitely going to need some additional cleansing. I knew there were a ton of bees in there, but I had no idea the number of larvae of all sizes! First time dealing with that stuff, and it was full of surprises!
Too bad I didn't read that before I went to the thrift store. My plan at this point once it's sufficiently cleaned up is to cut it into chunks per batch roughly by weight and/or by an appropriate volume for the samples. The muffin tin idea may be about perfect for suspending over a pot filled with boiling water to get the wax/oil to melt in little batches all at once though...
What's the story on the propolis? Why is this a good thing?
I was thinking sous vide, equipment... Might be a good thread for research to find some ways to manage the temperatures necessary. Good to know about the iron setting as well. Hadn't thought of that. An upturned iron that has a pretty steady state in the desired range could make for a much simpler heating element for a hot box of sorts... Or maybe for muffin tin cups (just cut them apart).
What about light bulbs? Incandescent bulbs make great inexpensive resistors if you don't need much in the way of accuracy. They may also make a reasonably predictable amount of heat... Hell, a straight up resistor might even make some predictable amount of heat come to think of it... Typically the only thing of concern there is getting rid of the heat, and the rule is overkill for margin of safety. My physicist friend has tons of old electrical junk in his shop (he's into electronics like I'm into cars), and I KNOW there are some heavy duty heat sinks... It's not a huge leap to think that there might be heavy duty heat sources to match... Certainly not the most efficient way to go about it, but for getting controlled heat for a few hours without spending a ton of money may be worth the exercise in electron excess.
Can a typical cooler handle 150° for an extended period of time?
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Met up with the apiarist today, and when I said 'raw beeswax' I had something in mind along the lines of a block, solo cup-shaped, or bowl-shaped body of wax peppered with whatever little bits here and there... The apiarist, obviously closer to the situation and more familiar with the goings on of an apiarist, had something entirely different in mind. I brought a clean gallon ziplock bag with me in case the beeswax was prone to leaving residues (maybe still had traces of honey in it or something?), and it's a good thing I did because his definition of 'raw beeswax' required such a container! I have a gallon of loose and fluffy little flakes, chunks, fully formed honeycomb, grass, dirt, and desiccated bee corpses. Not what I had in mind, but I guess it only adds to the experience! "Authentic", I think they call it. Anyway, I picked up some cheese cloth on the way back for obvious reasons. This will be fun!
Next step is designing the experiment in terms of mixtures, vessels, temperature control, etc. According to the literature, vegetable tanned leather starts to 'go bad' between 140-160° depending on the quality. I'm not sure exactly what that means in 1916 terms, but I'm going to hope the majority of the leather a century on is from the higher quality end of the spectrum... It had better be, because beeswax melts between 145-150, and that's hot enough to ruin about half the spectrum of leather qualities. I'm trying to figure out what vessels I can get my hands on that will either be easily cleaned of the beeswax/oil residues or are recyclable and can handle the temperatures. I'm using boiling water as my testing fluid/temperature (upper limit on temperature while melting/mixing wax), and I've already ruled out the bulk food containers from whole foods (too bad too, because the smallest ones are an excellent size and shape for my needs). I'd hate to waste some small canning jars in the event I can't get them clean... Dropping room temperature leather into hot wax will result in a wax shell around the leather instead of the desired penetration, and according to the literature, getting it as close to the temperature of the wax as possible will lead to the best results, as you can just drop it in and let it soak until it stops bubbling (assuming the wax isn't too hot), then pull it out, put it back in the oven and let the excess drip off or soak out into some absorbent cloth or something (I don't remember exactly what, if anything, was referenced in the industrial application being described).
The samples that are simply intended to be oiled will be about as straight forward as you can get. The bellies I'm using to test are about as dry as you can get having been in storage for as long as they must have been in a dry climate, so I'm entertaining the idea of introducing a moisture element to the mix. One set of samples is dry as a bone (maybe even another set dried further in the oven while tempering the leather destined for wax treatment), one set cased a day before, and a last set cased shortly before oiling. Moisture is said to be instrumental to proper oil penetration. The mechanism described is as the water evaporates, it draws the oil into the leather, and if the leather is too dry, by the time you get full penetration to the inner parts of the leather, the outside is too saturated... Might as well give it a shot while I'm making a mess.
I do have some canola oil in the pantry, so that'll end up in the mix. I thought I had some coconut oil as well, but that seems to have ended up in a cake... Oh well. Canola is the most extreme unsaturated:saturated oil I have on my chart at 15.7:1 (62% mono, 32% polyunsaturated). Coconut is on the other extreme of my chart at 0.1:1 for reference. I also have some ghee (rendered butter) in case I want to tref (de-kosher-ize) things up a bit...
Does anyone have any ideas for temperature control in the desired range and mode? Modern ovens don't go below 170° due to food safety concerns, so that would be a very touchy way to go. I have a slow cooker, and the 'warm' setting on that might be in the range, but I fear the fear of litigation might make that not suitable in the same way. It's possible I could construct an insulated box, rig up a temperature probe, a heating element, and some sort of controller, but that's a lot of work for what could easily be nothing more than a goof off experiment... I need to hit and hold steady within +/-5° of 150°... Oh... and I need to do it X2... Once in a device to bring the leather up to temp and hold it there, and another to bring the wax up to temp and hold it there across multiple small jars/samples. I have an IR thermometer that I could use to monitor things on the fly if need be, but that could end up requiring quite a bit of juggling for one person.
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Thanks!
I've put together the start of the above mentioned lipid chart. With all the health claims (imagined and otherwise) surrounding so many oils, I'm having a hard time finding complete information on a lot of them. I also need to track down the decomposition byproducts for the various fatty acids to see where I can get my vanilla notes and what's going to make things smell like formaldehyde.... In the meantime though, I picked up some walnut and flax oils, and I have a steady supply of olive oil on hand at any given time. I'm not even going to bother with neatsfoot oil out of boredom. I've used it (so has everyone else), I know what it does, and I really don't need to see it again. That said, I think I'm going to try to track down some beeswax to round out my lipid collection (sorta)...
Flax/linseed oil: This, combined with pigments and polishing, is what was traditionally used to make patent leather before the advent and mass availability of petrochemicals. Leaving out the pigments and polishing should make for an excellent protective polymer coating at the surface of the leather penetrating down as deep as oxygen is able to penetrate the fiber matrix/polymerized fatty acids. Flax oil is ~53% a-linoleic acid (which is why it's so popular as a dietary supplement) with only ~10% saturated fat and ~21% monounsaturated (compared to ~28/60/2 for neet/neatsfoot and 16/71/10 for olive), so it won't necessarily be the best lubricant for the leather fibers after the polyunsaturated content has broken down and migrated. Mixed in some proportion with some heavier oils, reasonable levels of lubrication should still easily be achievable. Mixed with beeswax might be interesting as well, but the polymerization of the a-linoleics in the flaxseed oil might just be unnecessarily duplicative in the surface finish/darkening effects of the beeswax and I'm not sure it would really be a worthwhile result for anything save thoroughness. I know flax goes rancid in the traditional sense (with the foul odor from whatever aromatic byproducts) very quickly and easily (which is why it's sold in small quantities, in opaque bottles, and refrigerated), so the flax-only sample will be a great stress test for the way the leather deals with unpleasant aromatic compounds. The unsaturated:saturated fat ratio is pretty high at roughly 9.0:1. There are more extremely polyunsaturated oils (i.e. almond, safflower, and canola oils), but with the exception of almond (a potential allergy concern for some), these aren't especially interesting beyond a cost perspective. I might have some canola in the pantry, and if I do I'll give it a shot just out of convenience.
Walnut oil: This has a fairly high concentration of polyunsaturated acids (similar to the flax), but the double bond is in a different place and the resulting decomposition byproducts are not the same. That said, it's still a traditional wood finish, and there is still some polymerization of the fatty acid byproducts from decomposition. It also has a pleasant earthy smell, so this will be a nice test of that part of the puzzle. It has slightly less polyunsaturated content on the whole compared to the flax oil, but it's what I was able to find at the grocery store when I was looking for the flax oil that I could (incorrectly, it turns out) remember the rough fatty acid composition off the top of my head. I meant for it to be a better middle ground between the olive and flax oils, but it's still one of the oils I had in mind initially, and worst case scenario I can always cook with it or take it out to the wood shop. Where it does mix things up is the unsaturated:saturated fat ratio, which is very close to that of olive oil at 5.3:1, swapping monounsaturated content for polyunsaturated.
Olive oil: This can sort of be thought of as the control. It's been used many times by many people for many centuries with great success, and its preferable in my book on a number of levels to neet/neatsfoot oil. It shifts the fatty acid profile up the molecular weight classes predominantly to the monounsaturated range, but is otherwise on par with the walnut oil for saturated fatty acid content. The unsaturated:saturated ratio is about 5.1:1.
Beeswax: This is sort of a ringer... I think it might be the best way to get the color I'm after provided I can get the oil to wax ratios right. It's an awfully large molecule, and it might balance out well with some lighter oils... According to some of the literature I've read, a big part of the darker colors come from essentially slicking/flattening/smoothing the surface fibers to change the amount of surface area available to reflect light. Beeswax is about the most effective thing you can do to get this done quickly, though at the expense of flexibility if used exclusively. Cutting it with some lighter oil(s) may prove an excellent way to have/eat cake. I talked to another leatherworker on the phone last night who uses a beeswax/neet/neatsfoot oil mix regularly, and he says it's the bees knees (pun intended, all blame for tasteless puns lies with me though). Beeswax is another traditional leather treatment, though it results in very hard leathers. While it does have triglyceride content, it is far more complex than simply an oil. It seemed to me given the wide variety of products made with the stuff, that it should be able to be mixed with some oils to make a hybrid treatment similar to some of the other oil blends I read about. Unlike lard (straight up saturated fatty acids), beeswax doesn't have much that actually CAN go rancid... No risk of spue/spew, no risk of foul odors (on the contrary, it might impart a honey-like scent), etc. etc. Mixing lighter and (much) heavier oils to treat leather is (was) an extremely common practice and I can't for the life of me think of a reason this would be bad UNLESS it prevents mobility of the free fatty acids from the decomposition of the lighter oils to the surface... The challenge here will be temperature control... According to the literature, high quality vegetable tanned leathers start to go bad around 160°, and the lesser stuff as low as 140°. Beeswax has a melting temperature of 145°-150°, so unless the leather I have is reasonably high quality, it could be a completely incompatible finish. I honestly don't remember where it came from or what it is beyond a plain veg tanned side, but I'm using the best of the lot in actuality... Experimentally I'm using some belly scrap that would otherwise be destined for tool facings. Additionally, flax oil does NOT like high temperatures and will break down very quickly (same story with the walnut oil). Fortunately, the byproducts of the breakdown of these oils with heat are exactly the sort of chemicals that are desirable in the end product from a finish perspective... I called a local apiarist up, and I'll be headed out sometime tomorrow to pick up some raw beeswax (bee bits and all) to round out the collection.
It's possible I get itchy for something a shade more saturated, and if so I'll pick something up and share that information here. I also need to figure out exactly how I'm going to manage the temperature control for the waxed samples. I may check with my physicist friend/neighbor to see if he has any good temperature sensors in an appropriate range, and maybe we'll hook something up with a controller (arduino, raspberry, something like that) to keep it right in the sweet spot. If not, I'll use a meat/candy thermometer and wing it for the experiment phase.
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Alright, I'm done waiting and I'm calling it a day. I'm going to go out and get some work done on some fun projects. For starters, I'm going to see what I can do in terms of designing an experiment to nail some of this stuff down. I have some veg tanned bellies that I don't remember buying. From the look of what's not there, I'm going to assume I used them for tool wear/friction linings. Since I don't remember buying them, it's possible they were cut offs from whole hides... I really have no idea, but they're here and I don't have any real plans for them where they're so special that I couldn't just use some other scrap cutoffs or buy some cheap stuff from Tandy or other.
So here's what I have in mind:
Acquire a collection of varied and assorted oils according to research findings regarding relative fatty acid composition in very small quantities (hopefully I can find some place that samples such things).
Cut the bellies up into smallish pieces.
Find a means of hanging them such that there is some air flow and minimal risk of cross contamination.
Find a means of labeling the samples (probably nothing more complicated than a sharpie)
Oil them up,
hang them up,
check in every so often and take notes.
I figure reapply once a quarter maybe?
Total elapsed time... 1 year?
Thoughts?
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Well... I hit a snag on the software contract, and can't really do a whole lot more until I hear back from the client on some hardware specifications. I know they do occasionally work on Sundays, so I might hear back, but until I do I'm a bit stuck... So.... While I wait, it's time to dig into the second book! I'm 30 pages in, and already, if nothing else, there's a very distinct difference in the overall voicing... The words 'peculiar' and 'evil-smelling' are abundant to the point that one doubts the extent of the author's vocabulary... It's very interesting in its addressing of mechanical oils toward the end of the Victorian era as I have a particular interest in clockworks of that era. Neat read. The way it addresses rancidity and fatty acids, etc. is markedly different from the other such that I wonder what the state of the science was during the intervening decade and change... It's not quite back to transitional alchemy, but certainly not written in a modern scientific voicing like the other. Very cool book pairing for anyone so inclined. That is all for now.
Finally got to the part you referenced about neet/neatsfoot oil, violet glass, precipitates, etc. Very interesting, but also very much in period. Science clearly came a long way in the 13 years between the authoring of this book and the former, and it's come far longer since. The statement about the oil not going rancid for years is directly countered by exposing it to sunlight (intentional decomposition via UV light) and the filtering of distillate (crystalized fatty acids, again from decomposition). "Rancid" may be subject to vernacular here. To me, it means the oil has decomposed from a triglyceride to diglycerides, fatty acids, and beyond. It seems to the author, "rancid" refers to a specific "peculiar"smell that likely refers to a very specific class of aromatics and aldehydes that may be present in greater or lesser quantities in neet/neatsfoot oil. Personally, I always thought neet/neatsfoot oil smelled rancid when new, so I'm not sure it would be easy to tell in any case. I don't know the state of organic chemistry in 1906, but I think it would be a pretty safe bet that the technology required to discern the chemical composition of a complex organic substance like naturally derived oils (which all the oils discussed in this book would be classified as to a greater or lesser degree) either did not yet exist or were in such a state of infancy that the author did not have knowledge of access to them.
"Green vitriol" (pre-modern science's cousin Alchemy's word for iron sulfate)... Love it!
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My dad has a similar saying, albeit more colorful and with an emphasis solely on the wisdom part.
I've had the leather in my stash for a while, so it is what it is (this isn't my first leather project by a long shot, just the first down this particular path). The first part is already cut, riveted, and sewn ready to layout for carving. I'm trying to avoid dies and other heavily manufactured things. As with food, the simpler and more pronounceable the ingredients the better. I've got a pretty solid understanding of oil applications by now (the theory lines up with my experience), it's the specific chemistry I'm seeking.
Tell me more about your lacquer suggestion. What sort of lacquer, specifically, do you have in mind (I assume you're not referring to lac beetle secretions in solvent)? Have you used it? How does it hold up?
As for the scent, I like the smell of regular ol' leather too... What IS the smell of regular ol' leather though? That's the rub (pun intended). Let's be honest, not all leather smells the same in quantity or quality, and the question of the day is why? Olive oil is frequently touted as an excellent leather treatment, but some say (somewhat truthfully, though not in the way they intend) that it goes rancid in the leather. This would seem on its face to be a bad thing, but I've never personally seen anything like that occur in real life... Why? I read that cod liver oil is the secret to that beautiful old English leather aroma. Why? Similarly that Neatsfoot oil is the only option for leather treatment? Why? Also, any time anyone makes broad absolute statements, alarms go off in my head that that person has little to no clue what they're talking about, and the subject bears investigation; when MANY people within a 'tribe' (referring to the 'tribal knowledge' mentioned earlier in the thread) say the same thing, it implies there is some serious and widespread lack of understanding or misinformation afoot and then the game is on!
At this point, I can say with some authority that the "smell of regular ol' leather" is a direct result of the applied oils breaking down (rancidification) and the resulting aromatic compounds that are released from the leather. The variety and proportion of these aromatic compounds will be directly affected (and can thus be directly controlled for) by the fatty acid composition of the oils from which they originate. It would seem at least some of the aroma (the word we use for smells/odors/stenches/etc. when they are subjectively considered pleasant) comes from the byproducts of heavier oils and thus longer chain fatty acids, but what part and how much?
One of my many avocations is that of luthier; I've made several instruments, taught clinics, have written on the subject, and have even been invited to guest lecture in a university setting. Something the more adept luthiers are good at is being able to break down a fleeting and somewhat subjective sensory experience into component parts and manipulate them to be subtly more pleasing; bringing out harmonics in different ranges to affect the voice of the instrument. Timbre, as a mixture of disparate mathematically related frequencies in proportions relative to each other, is not dissimilar from smell. A similarly subjective, fleeting, and barely communicable sensation. How something looks is only part of the total experience. How it feels and smells (and sounds and tastes, but we're considerably less concerned with these from a practical standpoint) are just as important. We dislike cheap Chinese-made junk (radical overgeneralization for the sake of illustration) because it may LOOK appealing, but by the time you get up close to it and investigate it more thoroughly with your other senses, it breaks down entirely (again, pun intended). I have specifically in mind a piece of chocolate obtained in Beijing that looked especially attractive, but tasted like wax and nothingness; nothing can be more off putting than having expectations unmet (just ask Seneca). It's like the uncanny valley in robotics (I've been working on a contract to write a thin AI engine for a local robotics startup these past few days, and it seems like a pertinent analogy), the more it appears to be what you expect without achieving Turing levels of aesthetic indistinguishability, the more off putting it is. If I were to create this piece of leatherwork that looks absolutely stunning in every aspect, but felt like plastic and smelled like garbage (or nearly as damningly, nothing at all), it would be wholly off putting (to everyone that wasn't merely looking at a photo on the internet).
Updating the current plan of action as it relates to the immediate phase of the larger project: I'm going to investigate and probably make a chart/list/spreadsheet of various oils that I can readily obtain in sufficient quantities and at reasonable prices, and detail their fatty acid composition, percentages, saturation levels. If I can find the information, I'll see what I can do about nailing down the decomposition elements and see if I can't come up with some correlative understanding as to what smells pleasing on paper. Essentially, if neet/neatsfoot is the norm, olive oil is nothing out of the realm of expectation, and cod liver is somehow ideal, then compare them and figure out what they have in common.
One of the more pertinent takeaways from the 1919 book on oils and greases in leather was that of how to affect color. For starters, many things stated in the book were directly counter to my goals as I am hoping to achieve a fairly dark color, and it seems the fashion of the time dictated that lighter colors were a highly sought after norm (there is quite a bit in there about how to lighten leathers, etc.). The way this is achieved is by smoothing and slicking the fibers on the surface of the leather; essentially wetting them down. A non-wet way of doing this would be some sort of lacquer or a level-able hardened surface coating. One pretty excellent way of doing this, taken from the production of patent leather, is to use flax/linseed oil. The a-linoleic acid oxidizes at the surface of the leather and forms a polymer coating. This coating, when heavily applied, polished and mixed with colorants, is what gives patent leather its sheen. Less liberally applied, I think it would be a pretty excellent way within my aesthetic parameters to achieve the darker color I'm after (assuming there are no negative effects from hardness or impermeability of this polymer coating). Unfortunately, the concentration of shorter fatty acid chains and subsequent dearth of longer fatty acid chains could have a net negative affect on the aroma and suppleness of the leather, and thus it may not be suitable as a standalone treatment. It may be required that it be mixed with a heavier oil (TBD). Further, if the only part of the flax oil I'm interested in is the a-linoleic fatty acids, there are myriad other sources, some of which come bound up with other aromatic compounds (and water, which helps with the oil penetration). These other aromatic compounds may be too tightly bound in the leather or too fleeting to be of any real value, but just as the mechanical properties of the leather seem to slow and diffuse the negative byproducts of oil rancidification, they may similarly slow and diffuse the release of these aromatic compounds such that the leather smells additionally and subtly pleasing for a long long time...
So long term, I have some bellies that will make excellent oil treatment test subjects. Short term, I need to get something figured out for the immediate project between now and when it comes time in the current phase of the current project to oil the leather. I may see if my biochemist friend would indulge me, and see if we can't come up with a way to intentionally create a concentration of some of these aromatic compounds in a controlled setting either in her lab or here in one of our kitchens or garages or something. Getting an idea for the smell of certain things in isolation will make it considerably easier to build a desired aromatic timbre. Even more short term, I need to eat a (very late) breakfast and finish this AI engine code while it's too cold and snowy outside to work on some of the other projects on my 'to do' list...
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Finished book one as justification for a late start on a paying project with a tight deadline this morning. Interesting bit about amides and lecithin from egg yolks as being a particularly premium treatment toward the end, then a final footnote on a concoction of varied things as something of a 'scholarly pursuit' (sounds right down my alley...). Last little bit of reportable interest was the role of sugar, something else, and specifically glycerin as a softener. They seem to work by attracting moisture. This is noteworthy because as the fats break down, they're essentially migrating toward being free fatty acids and glycerin, and that would further explain some of the mechanism in play. My goal with reading that particular book was to gain a better understanding of the role varying types and weights of oils play in leather, and I dare say I got more than my fair share! I've linked it below, and strongly suggest it. The science is old enough that anyone scientifically literate should find it a quick and easy read, and it was written in the US within the last century (barely) so there are no odd linguistic stumbling blocks or having to mentally convert 'f's to 's'es as you would going back a further century.
https://archive.org/stream/applicationofoil017193mbp#page/n1/mode/2up
In summary (combined with other posts in the thread on the subject), according to the author darker color (which it seems was undesirable at the time) comes from the fibers being smooth and matted and absorbing light. Makes sense. To get this to happen, the surface needs to have a fair amount of oil content, but then you have issues of oiliness and greasiness and risk oils coming off on clothing or whatever. The section on patent leather and the polymerization of a-linoleic acids makes me think lighter weight oils might be a pretty excellent means of having cake and eating it. I need to go dig out some woodworking texts on boiled linseed oil finishes (same polymer) and see about flexibility and permeability, but I think this might be a very promising route. Fortunately for my other motives, many of the pleasant smelling oils I'm after tend to have very short fatty acid chains of the a-linoleic persuasion, and I may have found the solution I'm seeking. I need to see if I can figure out which aromatic compounds, aldehydes, etc. are generally considered pleasant and which are best avoided. Diffuse as they may be off properly treated leather, it would really suck to find that whatever pleasant smell (which would also be diffuse) was overtaken with time by something stinky.
Unfortunately, the time scale required for proper investigation of the options is beyond the scope of my most immediate project, and I need to have something nailed down by this time next week or so. I have so many irons in the fire that the project is moving at a glacial pace (compared to other things). I'm going to read TinkerTailor's referenced book next, and hopefully it gives me some further useful insight. Short of that, I'll have to see if my biochemist friend or I can dig up something that describes the odor of various decomposition byproducts of some of the oils in question between now and then.
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You mean everyone doesn't put this much thought and attention to their furniture preservation? Water damage on fine walnut furniture is a killer!
Mayhap the atelier is part of the goal... Mayhap the skill and the knowledge is the goal, and a given project is only a means to an end... I have a particular affinity for skills and disciplines that combine art, science, and technology in a practical and aesthetic combination. In my shop you'll find tools, supplies, and materials for general mechanics, metalwork, wood working, luthiery, music, watchmaking, automotive restoration, cooking, baking, brewing, fermentation, software development, graphic design, and of course leatherwork. Probably a half dozen other things if I were to go for a stroll out there and look around. My bookshelf is even more diverse. I've been told by multiple people unilaterally and independently that in the event of a zombie apocalypse, they want to be in my band of survivors.
The project boils down as follows:
-Vegetable tanned leather (I think it's the nicer end of something from Tandy in the 5-6 oz. range)
-Carved with a reasonable amount of detail (topographical map of a meaningful section of mountain range)
-Needs to be reasonably supple, soft, and flexible
-Desired color is a fairly deep walnut brown, finish (matte/gloss) isn't especially important either way
-Color can not bleed from rubbing or contact (think use case in terms of clothing item or tapestry)
-I have a strong desire to use no man-made/petrochemicals as part of an overarching theme to a collection of work
-I think it would be neat to use an oil that smells nice
Suggestions?
I was digging through the wood shop last weekend for a bag of tiny little clamps, and found a roll of miscellaneous leather that somehow ended up somewhere it shouldn't have. I unrolled it just now, and there's some vegetable tanned belly cut offs that I might use for experiments as soon as I decide what avenues I want to explore. The time required to get a knowledge base sufficient to design and carry out the appropriate experiment and see them through to completion could take months or years... I intend to have the current project done long before then.
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Page 29 of the pdf, they talk about the ph of oils and how it changes as it rancidifys due to the presence of free fatty acids forming. It also clarifys what are called neutral oils, which are oils that do not have the free fatty acids in a fresh state which change the ph, such as rapeseed(canola) oil as well as olive oil. They imply that some oils have the free fatty acids when fresh and are unsuitable for use with metal due to corrosion issuesdue to Ph. I would imagine the same thing applys to leather. They also get into drying vs non-drying oils, linseed oil, for eg, is a drying oil and is not very suitable for a lubricant and presumably a leather dressing, while it is used in recipes for leather varnish.
Free fatty acids are the result of the decomposition of the triglycerides into diglycerides and free fatty acids. This typically takes place as oxidation where the oxygen binds with the hydrogen atoms hanging off the molecule in the kinks at the double carbon bond. When that happens, the 'tail' breaks off, and the larger part of the molecule (the part with the glycerine 'backbone') is the diglyceride, and the tail that broke off is the free fatty acid. The number of double carbon bonds is what makes it saturated (0), monounsaturated(1), or polyunsaturated(2+). An oil (triglyceride) is, molecularly speaking, a glycerine molecule with three fatty acid molecules hanging off the side (think "E", but with really long and occasionally kinky arms), and the properties of a given oil are dictated by how many carbon atoms are present in each of the fatty acid tails. The range is typically 16 carbon bonds up to the low 20s typically in naturally occurring stuff. Longer carbon chains typically come from animal or artificial sources. Blah blah blah... All this is background to say the free fatty acid content of an oil is often an indicator of quality since the oil, by definition, is the whole triglyceride. Any fatty acid composition means the oil was extracted in a fairly destructive way (i.e. excess heat) or was allowed to oxidize. As the triglycerides are broken down, the availability of hydrogen increases and the pH drops. This acidification increases the reactivity of the oil, which then is more likely to form metal salts when given the chance; in chromium tanned leather this may be more of an issue depending on how the chromium is fixed (though I think it's already happily locked up in a salt), but I doubt the same sort of reaction is a concern unless the animal in question ate more than its fair share of beans (the only thing I could think of aside from molasses that was especially high in iron).
Page 102 is a writeup on neetsfoot oil and a comment about how many sewing machine and clock oils are bleached neetsfoot repackaged in tiny bottles and marked up.
pg 119 is the recipes for the fine machine oils. They also talk about freezing neetsfoot and straining out the oil that is still liquid to purify it. Also bleaching it in the sun using violet glass.....Had they discovered uv treatment? They did notice purple glass bleached it better for some reason.
Page 114 is an interesting recipe for leather belt dressing to prevent slip made from ~90% castor oil and 10% tallow.
Heavier/longer chain (synonyms in this application) oils tend to make especially good lubricants. I do not know the reason for this.
Page 142 is where the good stuff starts. The stuff relating to leather. You will notice that many of the recipes for shoe polishes etc contain sulfuric acid or soda, Presumably to make them strong enough for a man but Ph balanced for a woman.........Or is that deodorant?....rabbit holes are fun.........squirrel
Page 148 talks about ant-acid boot leather varnish .....acid free....The effects of ph on leather were DEFINITELY known at this time.
I have from my reading determined that as a leather treatment, tallows are the best treatment for lubricating the fibers and preserving the leather for a long time, however they are hardest to apply due to being mostly solid at room temp. Tannerys hot stuff tallows and waxes to make that expensive horween stuff. Temperature and exposure time are needed for the leather to take up the fats fully. These processes are out of the reach of the average user as they require special equipment and machinery and is better done in bigger batches of hides. The tallow lubricates, and the wax protects. Both are very long lasting before breakdown, if it even happens.
We as leatherworkers try to approach this on raw leather but without the prolonged heating and tumbling. Oils are the best solution to make leather treatments that are easy to apply. In order to apply the harder waxes and tallow, we often mix then with thinner oils to make easily appliable pastes and cremes.
I actually just read some about this very process. It seems the tallow is not the actual lubricant (unless in the context of drum stuffing or hot dipping), but a means of mechanically holding the suspended lighter oils in the paste to the leather so that it can absorb more of it over a longer period of time. Drum/hot stuffing and hot dipping are very interesting to me, but I'm not sure it will give me the specific result I'm seeking. With the heavier oils being solid at room temperature, when in the fiber matrix of the leather, they combine to make a very hard material. It's waterproof, attractively colored, and mechanically resilient, but I need flexibility.
The current plan (subject to change when I turn the page...) is that I might be looking toward some blend of oils. The idea of the varnish produced by oxidized a-linoleic fatty acids seems like it would color the leather very nicely, and also provide some protection. I need to learn more about patent leather though... I would be looking in that general direction, but without the coloration or the polishing and only if it doesn't introduce some otherwise undesirable qualities. Something heavier would be desirable as well for the suppleness afforded and staying power... And some essential oil may provide a wonderful aroma... So much still to learn... I have both pieces roughed out, and have one more template still to go before I actually start tooling... I need to have a plan by the time I finish tooling.
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You might look into how the collagen in the leather fibers interacts with the oil, too.
It's not come up so far in my readings. Heat and water in the liming phase would likely convert the collagen to gelatin. I could see the gelatin either dissolving away, or mayhap it's the dried (and hardened) gelatin that gives rawhide its mechanical properties... I'm also not sure the role the high pH from the lime has in gelatinization... Do you have something specific in mind or were you referring to something specific?
Just in case I didn't mention it above, TinkerTailor, I have the book you linked to open in another tab, and it's next on my reading list. I think your breakdown of the neet/neatsfoot preference is very apt, and I lean mostly toward #5. My dad calls that sort of thing 'tribal knowledge', and I think the concept applies very well in this case. No real science or understanding save "that's just how it is".
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Apparently I hit the wrong button on that last one... Spamming my own thread. Note to self for next time...
Anyway, my more educated friends and I have parted ways temporarily to go prepare our respective contributions to the holiday fare, and I figured I'd recap the conversation while it was fresh for posterity:
The question was asked about the pH of the leather, I said it was generally between 3 and 5, and we agreed to that having an antioxidative effect on the rancidification process that wouldn't stop it by any means, but would certainly slow it down. It was agreed that the theory regarding the mechanical properties of the leather would likely slow the propagation of free fatty acids to the surface of the leather, and it was suggested that a vapor pressure test should confirm this pretty readily (mayhap the physicist of the pair has the appropriate apparatus handy in his lab, but it wasn't pursued further). These things in combination would undoubtedly slow, further slow, and diffuse any undesirable aromatic byproducts of rancidification, and this seems to answer at least that portion of my line of questioning satifactorily. There was talk of what specific aldehydes and aromatics were in play with the decomposition of the various fats in question and whether and what would be un/desirable among them. Then the phones came out and a search for scholarly papers on the subject ensued; I can't get through the pay wall since I'm just some guy, but they're both employed at a major university as researchers so they slip right on through. Unfortunately, they quickly discovered what I had already known; that, paywall or not, there doesn't seem to have been much in the way of serious scholarly pursuit on the subject in the last century, and certainly not since the pre-internet barrier came to be. We then talked briefly about the oxidation/polymerization of the shortest of the fatty acid chains in question (specifically a-linoleic a la patent leather as mentioned above) and whether or not or how flexible and permeable the membrane would be, whether or not there was any benefit to somehow using an impermeable polymer membrane to retain a secondary tri/diglyceride/fatty acid combo and/or serve as an oxygen barrier to prevent degradation... Enzymatic, photo, and time degradation were then referenced and that train of thought sort of fell off the tracks, and then the cinnamon rolls were done. The final quote (according to my wife) was, "I don't know, but there's cinnamon rolls!" (in a thick German accent).
In short, we're a lot of fun at parties.
I doubt there will be much more conversation on the subject, as the beer is about to come out and our favorite brewery here locally just released a pretty excellent stout that we're all excited to try with the main course!
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On a side note because I found it interesting just now, Prussian Blue is listed as a catalyzer in the oxidation of linseed oil into a hard varnish... Seems like it might make a neat wood finish depending on the concentration of Prussian Blue and whether or how it's intended to be recovered after the reaction (it's mentioned in the previous sentence that the catalysts are often recovered and reused in the context of patent leather). I found a study on the subject of resistance to UV degradation of the coloring pigment, but nothing really about the combination as a wood finish... Yet another rabbit hole in an entirely different zip code (actually more of the same)...
A little rabbit hole traversal because I'll find some other shiny flittering thing in a few minutes and forget, it seems Prussian Blue and linseed oil is essentially the basis for blue oil paints, so it must stay in suspension after the oil has oxidized and hardened, so the idea has legs. It happens to be a shade within my wife's favorite color palette, and a significant portion of my life is roughly Prussian Blue, so it may unlock my ability to engage in more woodworking projects as well as stimulate my own interest therein since I don't care for chemically junk in my hobbies.
Another one... man... This archive.org is a freaking gold mine!!!! A Japanning recipe that sounds super easy and doable for tools... Boiled linseed oil, Prussian Blue, and vegetable black (finely ground carbonized whatever vegetation)... Nothing special anywhere in the mix, and Japanning is one of those 'lost arts' in that space. I've got a big engine coming soon for an automotive project, and I was going to use some sort of simple paint on it, but I may just Japan the big ol' bastard for the hell of it! That would be super cool!
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On a side note because I found it interesting just now, Prussian Blue is listed as a catalyzer in the oxidation of linseed oil into a hard varnish... Seems like it might make a neat wood finish depending on the concentration of Prussian Blue and whether or how it's intended to be recovered after the reaction (it's mentioned in the previous sentence that the catalysts are often recovered and reused in the context of patent leather). I found a study on the subject of resistance to UV degradation of the coloring pigment, but nothing really about the combination as a wood finish... Yet another rabbit hole in an entirely different zip code (actually more of the same)...
A little rabbit hole traversal because I'll find some other shiny flittering thing in a few minutes and forget, it seems Prussian Blue and linseed oil is essentially the basis for blue oil paints, so it must stay in suspension after the oil has oxidized and hardened, so the idea has legs. It happens to be a shade within my wife's favorite color palette, and a significant portion of my life is roughly Prussian Blue, so it may unlock my ability to engage in more woodworking projects as well as stimulate my own interest therein since I don't care for chemically junk in my hobbies.
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My flax oil experiment seems to have been put to bed somewhat... It has a high a-linoleic acid content (short chain polyunsaturated), and when it rancidifies and the fatty acids break off, they oxidize and harden to form a varnish. Another more traditional name for this oil when it's not used for food is... Linseed oil (I'm a wood worker... I should have known that!). Traditionally used in making patent leather. I'm seeing it referred to as Japanning, which is an antiquated term for applying a hard black lacquer to something, and I normally see the term used regarding black enamel on very old cast iron tooling... I wonder if linseed oil was somehow used there too... Yet another rabbit hole, but one that takes a second (or third or fourth) seat to the current train of thought since I have an active project in progress while I figure out this next step.
So here's a little bit of circle closing... The whole "neetsfoot/neatsfoot is the only option" thing, pretty sure we can all agree that was never anything more than bunk and hooey, and oils from the opposite end of the fatty acid composition spectrum not only CAN be used, but are primarily used in certain contexts. I'm not ready to commit to something extreme and weird yet for my own current project, and every time I turn the page there's some new and exciting means of imparting some new and exciting variety of lipid into tanned leather...
I have the book you suggested open in another tab in the browser, and I'm right about halfway through the one I'm currently parsing through. I have cinnamon rolls proofing in the oven at the moment, I'm drinking my morning black stuff, then all the Thanksgiving cooking excitement begins, so the reading may be a bit light today. I mentioned above that my German biochemist and physicist friends are coming over to join us in the consumption of many things, and I guarantee we dig into this topic (the wife's O-chem background may be very helpful in distilling a few questions I haven't yet resolved), so hopefully some casual chemical conjecture can make up for the lack of of reading time today!
I guess the next part of the question that I didn't realize had so many parts, is essentially how 'essential oils' would play. They have a heavy triglyceride component, but there's also a significant amount of water and 'other' with the molecular content of the 'other' being a lot of small aromatic compounds. It's one of those things that certain people ascribe certain 'magical powers' (my words) in a health context without anything resembling critical thought, so it's not exactly proving a simple task to weed out the BS and get to some science on the subject. Plugged into the scientific community and familiar with the social constructs therein as I am, I feel it's probably a social taboo of sorts for any serious scientists to really dabble in it since it's so weighted down with the fluffy nonsense of the aforementioned cultural elements and could be perceived as damaging to ones' reputation and career. So... Good luck finding any hard reading on the subject, me.
I think the best thing here might be to go about it indirectly and see if anyone has ever heard of some ultra-amazing-super-premium-first-born-per-square-foot tannage imbued with the special magical powers of rose oil. Rose oil is probably one of the highest profile substances through history that falls in the 'essential oils' camp, it's been around forever and ever, and if it isn't completely ruinous to the leather, I'm sure someone somewhere would have done it and charged insane quantities of currency for the pleasure of its care taking or ruin, and that person would likely have been very proud of their status as caretaker/ruiner and talked about it. What's more for the historical subset this might apply to, those people could have had literate people with pens and paper/vellum/tree bark under their employ and such an asset could have made its way to some sort of inventory type document... Maybe a bit of a stretch, but maybe not. Anyone know/heard/vaguely aware of such a thing that could tell me what it's called or where to look?
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I'm hosting these from Google Photos. I got really fed up with Photobucket a few years back right around the time Google came out with the photos service. I'm a software engineer by day, and Google's offerings are generally very highly regarded. So far, I've not been disappointed.
One of the biggest takeaways from my research in the broadest sense was that there really isn't a bad oil. There are pros and cons to pretty much all of them, and neetsfoot oil is not special in any way save mythology and lore. Actually, I take that back. It smells like crap. It's pretty special in that regard... Olive oil is very close in terms of lipid composition, and it smells nice and I don't mind if I get it on (anything).
Actually, one of the reasons I'm thinking neetsfoot oil might be so common is that when petroleum oils displaced it as machine lubricant, light colors were in vogue (B/W TV showed that cream color pretty well). These days, it seems the rich dark mahogany-esque colors are more desirable, and in that regard, neetsfoot is not very good at all. Rapeseed (canola) oil, and an oil wax blend have had the best results for darker colors so far. It's all in how they interact with light when combined with the leather fibers.