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

[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.