Mineral oil bad for leather? Or good? Or neutral?

[SUP]

@fredk you hit the nail on the head. 

Incidentally, oxidation of oils produces peroxides as well as  alcohols, aldehydes and ketones, among other things. Not what we expect to put on our leathers. 

Oils oxidize on contact with the oxygen in the air - they smell unpleasant, or not, based on the exact type of chemical produced. But just because there is no smell, it does not mean there is no oxidation happening; it just means that the products are of a type that do not have a strong smell; longer chain versus short chain fatty acids but that is going too technical..

It suggests that oils should be stored in air tight containers to prolong their lives. And maybe used lightly on leathers, except dry leathers which needs lubrication.

Maybe some sort of anti-oxidant could be used as well. Need to look that up.

 

[dikman]

An interesting read, Fred. When I first got interested in leatherwork I did lots of reading about it (still do) and I was adamant I would only use natural products to treat it - pure neatsfoot oil, beeswax, olive oil, lanolin  - no petrochemical products. My thinking has now changed slightly in that perhaps pharmaceutical/food grade mineral oil might not be the evil product that I originally thought. It's use certainly makes it easier to concoct the thin pastes that are commercially available (I tried using pure gum turpentine as a thinning agent once, but over time it left a black residue in the tin I had the wax in so I won't use that again).

[fredk]

8 hours ago, chuck123wapati said:

Its going to be an interesting experiment. 

yes, and a long one too. I hope I'll still be around long enuf 

[fredk]

I won't start the oiling just yet. I don't have enuf 3-in-1 and I'm out of olive. I'll not be shopping until Monday or Tuesday next week

 @SUP, I might be teaching 'granny to suck eggs'  - remember to measure the quantity of the oil you'll be putting on your leather so each piece getting that oil gets the same amount. You don't need anything special to measure, a soup spoon, an egg cup, an aluminum or waxed paper bun case

We are on page 3 now. This is gonna end up a loooong thread  

PS; I'm going to keep a note book. I'll divide it onto sections so each test piece can get its own report

Edited September 22, 2023 by fredk

[chuck123wapati]

17 hours ago, SUP said:

@fredk, good to hear about the leather in your car and other older cars. . It appears more and more likely that it is not the type of oil, per se, that damages leather. Engine oil, being non-organic, should last forever, like mineral oil. Organic oils are fine as long as they are not exposed to air over long periods. Even the olive oils that  I hear were fine over 1000s of years, were in airtight containers.  So air is the villain, it appears, specifically Oxygen. Wonder what the products of oxidative damage of oils are? Do they damage leathers?

 Lots of more research needed.

@chuck123wapati yes it is.

I wish more people would join in, with the oils and leathers they have and in their locale. 

 

I may do that my area of the world is very dry humidity wise, so dry in fact i have found leather shoe pieces out in the old homestead dump's that have been laying on the ground for at least a100 years. Another thing to think about is viscosity of the oils used and its relation ship to the process. oils will at some point migrate out of the leather just due to gravity, lighter oils moving easier through the leather fibers may be lost sooner, its another reason we have to add oils over time. You may want to think about what your pieces are going to be laying on or in as they also could wick the oils away from the leather.

I do have some rendered elk tallow I could try, as well as the manufactured product i use. wish i had some bear grease it was traditionally used as well.

[SUP]

@fredk Yes of course. A proper experiment.  I don't mind your mentioning all the steps to take. It has been a while since I even stepped into a lab. Good to be reminded. I will measure  and maintain proper documentation. Just a tad busy right now so will probably get everything set by Sunday.

I have been investigating what is used to oil-tan leather - it is not really tanning as much as a treatment of chrome-tanned leather, where the leather is immersed in oils/fats. What I have discovered  is that in earlier times they used to use fish oils but now use synthetic oils and complexes. I plan to call a leather store here to see if they can direct me to someone who can give me more information. Since oil-tanned leather is already well exposed to and impregnated with oils and waxes, our results will be skewed unless we know what is used, at least in the leather I use. So I will start with veg-tanned leather and do the oil-tanned leather if I get all the relevant information.

@chuck123wapati welcome to the experiment. Tallow is something to which I do not have access, so that is a welcome addition,

The surface on which the leather is kept will be a part of the documentation.

I think, @fredk, once we have everything set, we could share  procedures, so we all follow the same methods. 

 

  

 

[fredk]

Tallow is something I cannot get or make. Due to the UK having BSE* in cattle a long time ago its illegal for butchers to sell beef fats and other parts and even porcine fats and parts are restricted but for another reason

But I may be able to get pork fats, but not for a while

Anyway, I have enuf oils to test

I don't think we need copy each other's tests, but I think they'll be similar anyway. 

I'm off to the shops soon to get supplies

 

*BSE = Bovine Spongiform Encephalitis

 

[Sheilajeanne]

10 hours ago, fredk said:

But I may be able to get pork fats, but not for a while

Fred, all I need to do for that is to fry up a pan of bacon!  (and strain out the bacon bits afterwards.)

Not so very long ago, farmers never thought of buying fat at the store. It all came from their animals - tallow from cows, lard from pigs, goose grease, etc. And the indigenous leather supply company I sometimes buy hides from has an ample supply of bear grease, which, unfortunately can't be shipped outside of Canada. 

Excellent research on the bees, Fred! Well done!

[SUP]

@fredk, no we don't need to mirror the experiments but they need to be similar and, like you said, probably will be. 

Animal fats like tallow, bear grease etc. I leave to others. At the most, I can do lanolin, which I do use in my leather conditioner anyway.

@Sheilajeanne, won't bacon fat smell of bacon? So the leather will too. And an invitation to mice and rats?

[Sheilajeanne]

Sup, yes my thought exactly. But how is it any different from pork fat (lard)? Or beef tallow? Even neatsfoot oil is just processed fat from the lower legs of cattle: 

Quote

The lower legs of slaughtered cattle (less the hooves) are boiled, skin and all. The fat that is released (as an oil) is skimmed off, filtered, and pressed. The first pressing is the highest grade; the second produces both a lower grade and a solid press cake or stearin product used, among other things, to make soap.^[1] 

 The fact it was processed didn't stop the mice from nibbling on my tack! 

I looked up how to make pork lard for cooking. You can do it yourself. You basically put the pork fat in a strainer, and heat it in the oven for 4 or 5 hours, with a Dutch oven or other large pot underneath the strainer to catch the fat. That's all there is to it - just make sure all  cracklings are removed.  

We've come to expect that everything we buy in the store goes through some sort of complicated process before being sold. And that isn't always the case. https://www.daringgourmet.com/how-to-render-lard-and-why-you-should-use-it/

Edited September 23, 2023 by Sheilajeanne