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

[fredk]

Excellent

I've done a piece with vaseline. It went into my special car at 07.00 today

Temperatures inside my special car range from 7.6* during the night to a high of 25.8* on a sunny day. On overcast days its about 20.4*

[SUP]

Instead of a vague description of 'very' or 'medium', or  'slight' I am making a scale of 1-5, for all descriptions.

 

 

[fredk]

2 weeks on and there are no nasties happening to my test pieces. Only, they're drying out. I think, this weekend, end of week 3, I'm going to give each another dose of their oils

[SUP]

I'm using the information I gathered from our experiment already. Seeing that coconut oil darkened leather the most and dried and hardened the leather slightly, I applied it on the 'hand' that I am making. The leather that Tandy provided was very pale and quite soft and I wanted the hand a little stiffer. Hopefully, this works. It already looks more human.. the color is much more life-life. The smell of the oil will disappear in a couple of days, leaving behind, I expect, a stiffer, darker leather.

[fredk]

Excellent

[fredk]

10/22 09.30 - up date

All pieces - no fungus

#2 has the faintest smell of oil (Rapeseed cooking oil)

All other pieces smell faintly 'Leather'

Pieces #3 (lard) and #4 (NFO Compound) are much more flexible than all the other pieces which  are all about the same, a little bit stiffer than Control Piece #2 which is in my leatherwork room

Night time temperatures inside the car dropped to about 5.6*, We have had a bad stormy weather the last week which gave very heavy overcast and cold days. Day time temperatures in the car was about a max of 7.6 to 8*

Later today I'm going to give all pieces another dosing of their oils

But so far it looks like all the oils or fats are fine with NFO Compound and Lard (pork fat) winning

[fredk]

I've re-oiled all the pieces and put them back in the car. at approx 11.00 10/22

I noticed that the backs of all the pieces have returned to very nearly the original leather colour but the fronts were  still dark. Except for #7 (Vaseline), both sides were actually a bit lighter than the test control piece

[SUP]

No fungus on any of the pieces in any of the locations. They appear to be slightly drier this weekend and curving a bit.

I plan to check them on Sunday - 2 weeks from the previous check, and determine which need oiling. I think I will oil as per requirements of individual pieces Then I will be able to determine which oils allow longer periods between oilings. 

[SUP]

This post is for 29th oct 2023 when I checked the leather but delayed putting it up here. 

Not much change in any of the pieces anywhere.

The only thing becoming more noticeable is that all the oiled pieces kept outside, constantly exposed to the elements, have darkened, to more or less the same extent now.  The unoiled piece is very pale compared to the oiled pieces. Texture remains the same.

This week is cold and below freezing. Let's see how that makes a difference.

 

 

[fredk]

I checked mine last weekend and yesterday

No change. Nowt happening in way of mould/fungus or bad smells. All pieces are getting a wee bit darker on the grain side but I think thats because they're getting direct sun light on them. All pieces smell faintly 'leather', with just a hint of the stronger oils on those pieces

A proper detailed check this weekend

 

[Nicbards]

So, what about cod (liver) oil? I'm surprised to see its omission here as it was the oil of choice for currying shoe upper leather, in conjunction with tallow, back into the mists of time until cod oil became unaffordable for tanneries and curriers. I've been using it to condition russet hide, I think with nice results. The drawback is you have to set the oiled leather aside for a few weeks for the oil to oxidise into the leather. This is the main benefit, other oils do not do this, and therefore wash out e.g. during blocking of boot vamps when you mellow the uppers.

Edited November 16, 2023 by Nicbards

[SUP]

@Nicbards Yes, we missed that. But then, I don't know if anyone here uses it now.  did not know it oxidized into the leather. That would make it a very good conditioner. I will see if I can get some, though the smell really gets to me. 

[Nicbards]

3 hours ago, SUP said:

@Nicbards Yes, we missed that. But then, I don't know if anyone here uses it now.  did not know it oxidized into the leather. That would make it a very good conditioner. I will see if I can get some, though the smell really gets to me. 

It smells fishy at first. But later it makes the leather smell great - just what you want to smell in a leather shop. There was another oil that oxidised in the leather, incidentally, which was Whale oil ("trayne oil") favoured by French makers. Apparently that really did stink. You can see some of my experiments with cod oil via instagram: 6am_shoemaker. I can't get the unrefined oil which is best, it seems to be unobtainium now. Drug store oil works but you have to wait a bit longer for it to stabilise.

[SUP]

@Nicbards I'm not on Instagram. Do you have it anywhere else?

 

[Nicbards]

1, https://www.instagram.com/p/CuOb6PYoJki/ 

2, https://www.instagram.com/p/CslEl_Vom9Y/?img_index=1

3, https://www.instagram.com/p/CyAftfCIo2C/?img_index=2

can you see the links? These are cod oil and then tallow (1 and 3) or just cod oil (2), the change in colour from plain russet / tooling hide is mostly from the cod oil. no dye.

[SUP]

@Nicbards That is just beautiful!. You say you have experience using cod liver oil. Do you have any leather that was treated with it from a while ago? Maybe we could add your experience to the knowledge in this thread. We are all trying to contribute our experiences as well as doing that experiment. The more people that contribute, the more the information available here. 

Cod liver oil is expensive though.

@Northmount if you could get the Instagram photographs visible here, everyone could see them, over time. Thank you.

Edited November 16, 2023 by SUP

[Northmount]

5 hours ago, Nicbards said:

can you see the links?

Please post your photos here as jpgs.  Then they are available for all to see now and in the future when users want to study this thread.

[Nicbards]

OK will post the pics here shortly. Nothing is that old yet because I've only been doing it about a year. Basically I've been currying the leather piece by piece for individual projects. I'm currently preparing some leather for shoe uppers so will post those when they are ready. Cod liver oil is expensive but I suspect could be made cheaply enough it you can obtain raw cod livers. You just leave them in the sun, fermenting in a plastic container for a week or two then get rid of the solids. I wouldn't eat it but the leather doesn't require gastronomic quality. The last remaining oak bark tannery over here in the UK I believe uses generic fish oil instead presumably because of cost, for currying its bridle leathers. Not sure how it behaves versus cod oil, but if you can afford why not use the time honoured product? I have yet to get through 1l of oil; it;'s not going to be major cost for a crafter unless for a large projects, though all these costs add up...

Edited November 17, 2023 by Nicbards
more info

[Nicbards]

@SUP thanks. I like the results so far, though should caution you can overdo it with the oil, in which case after oxidation you will have gummy droplets on the surface which have to be balled off. 

[SUP]

@Nicbards Umm. I think I will leave the making of cod liver oil to someone else. As it is, it smells strong. This process sounds stinkier(is there such a word?).

If you could see your way to putting up information on your cod liver oil treated leathers periodically, that would be nice.  I am a little leery of using it, because of the smell. 

[Nicbards]

@SUP well believe it or not there have been no complaints from my other half, who is rather sensitive to such things! Have not tried making it though, that would be another kettle of fish,

@Northmount Here are the pics posted earlier as links, for posterity

 

 

 

Edited November 20, 2023 by Nicbards
forgot the files

[Nicbards]

The making would indeed be smelly, strickly an outdoors venture. As it happens I've not been able to try it as cod livers are hard to come by too. Here are some pics from today's making. The black leathers are the same russet hide treated for use as handlebar grips for a bike. The same treatment has been followed, cod oil followed by tallow, after dyeing, since the oil and fat will in this case interfere with the uptake of the dye. After the leather was oiled and left for oxidation, I "boarded" the leather before adding tallow. This means folding it grain to grain and rolling under a board to break up the grain a bit. After that tallow was added giving a waxy finish.

The next picture shows a blocking vamp for a Derby shoe. More cod oil was used than on the grips to get a smoother texture. then  boarding and tallow as before. The effect of boarding is less evident because of the more supple finish. 

[SUP]

@Nicbards Thank you. Those are very clear pics and your explanations is as well.  

I need to put up my pics of the leathers treated with diff oils, kept in different locations and conditions. Been very busy with Diwali and now, Thanksgiving, Black Friday and Christmas around the corner!

Will try to do so soon.

Edited November 21, 2023 by SUP

[SUP]

Not forgotten!  

Sunday today and decided to take a break from gift making.

Two and a half months on, here are I am, with a photograph of the effects of the oils. I used mineral oil, mink oil, coconut oil and neatsfoot oil.

These are my observations  for today:

Mineral oil kept the leather the softest. The leather has a smooth feel throughout, and is not warped, except for the piece left outside which is very slightly curved at the edges but still feels smooth and supple.

Coconut oil kept the leather nearly as soft and smooth as mineral oil. It darkened the most of all the oils, although this is not very clear in the photograph. Also, no smell at all.

Mink oil dried the most and caused the most warping in all locations. It also darkened the least in all locations.

Neatsfoot oil  fell somewhere in between, dried but not as much as mink oil, darkened but not as much as coconut oil.

Controls: As expected, they dried a little over time, drying more outside and in the car than inside or in the garage. Also curved at the edges as they got a little dry.

Regardless of the oil, the pieces kept outside darkened significantly, including the control; the coconut oil darkening the most; mink oil darkened the least. So oiling is not needed to darken leather when kept in the sun but without oils, leather darkens only slightly. with oils, it darkens to a deep, rich color, even without dyes.

I do not plan to  re-oil the leather as yet. 

I keep planning to add more oils to test but hate the thought of a bigger grid, more conclusions to work towards. Just being lazy I guess.

 

 

 

 

Edited December 10, 2023 by SUP

[fredk]

Good report

I'll need to one now