Leather Heresies #1: Does Neatsfoot Oil Go Rancid?

[LeatherNerd]

I was in my local leather store a few weeks ago, and I asked the girl in the shop if Neatsfoot oil was made out of real Neets. Without blinking an eye, she said "Yes, but only the highest-quality stuff is 100% made from their feets."

In the serious part of my visit one of the guys at the shop told me he had heard from a customer that their Neatsfoot oil had gone rancid, and that this can happen with any other kind of natural oil conditioner. Logically this made sense to me, but in practice, some of ya'll are just puttin' that stuff right on there! Are you mad?!? He recommended that I go with Aussie Conditioner because it was a beeswax-based conditioner; no mention if the oils in it were natural or not. (For all I know I could be rubbing beeswax and 10W40 motor oil into my leather goods.)

So! Leather experts: does Neatsfoot oil ever go rancid? If so, can it be prevented, e.g. with regular maintenance, or perhaps applying a sealing top coat?

[Northmount]

I have some that is well over 50 years old. Was stored for years in a shed that was subject to hot summer days and -40 winter days. Still good.

Tom

[LeatherNerd]

Thank you! I think the concern was that it would go rancid in the leather itself, while stored open and exposed to the elements. Then again, rancidity is usually caused by anaerobic conditions; being open to the air makes oil evaporate or tar up, not go rancid. And 50 years is a heckuva a shelf life--enough to make me consider that the customer who had some go rancid may have had something else on his leather go bad.

...OR he could have bought some poor-quality stuff. Either way Neatsfoot oil is back on the menu, and I'll be making sure to buy trusted brands like Fiebing's. This stuff goes on and then stays on for years and years, so it's probably one of the worst products to try to go cheap on.

Thanks!

Edited November 7, 2015 by LeatherNerd

[TomG]

I got a bottle of neatsfoot oil COMPOUND a long time ago , and it did turn rancid. It has other components in it and I think those were what went bad.

I've had a can of pure NFO that was 20 years old and still good as new.

[impulse]

I think that you will find that any conditioner with beeswax has a high percentage of oils in it - usually neatsfoot - to make it creamy and spreadable. I always add a few drops of eucalyptus oil to mine as this helps prevent mould in leather.

[Norton Custom Leather]

? answered ………. no it doesn't, it always smells like that

[cgleathercraft]

Well if I can go buy a 55 gallon drum of Neatsfoot oil from Weaver, that tells me that it's unlikely to go bad anytime soon.

On that note - Anyone actually bought that much Neatsfoot oil at once?

[Tannin]

I have some that is well over 50 years old. Was stored for years in a shed that was subject to hot summer days and -40 winter days. Still good.

Tom

Sounds pretty convincing to me. Thanks

... He recommended that I go with Aussie Conditioner because it was a beeswax-based conditioner; no mention if the oils in it were natural or not. (For all I know I could be rubbing beeswax and 10W40 motor oil into my leather goods.)

So! Leather experts: does Neatsfoot oil ever go rancid? If so, can it be prevented, e.g. with regular maintenance, or perhaps applying a sealing top coat?

Oils going off is not always a bad thing: for woodworking, I use "drying oils", such as: linseed, walnut & tung because they polymerize when they oxidize or "go off".

I wouldn't be surprised if "beeswax & 10W40" turned out be a useful leather treatment - however, I'm thinking beeswax would inhibit the supposed ability of leather to breath. But I would think beeswax was used in traditional shoes polishes. It seems most combinations of oils/fats have been tried as leather treatments and there is also a school of thought that leather needs no treatment at all, the tanning took care of it, and that treatments inevitably compromise some properties of the leather.

Re. "can it be prevented, e.g. with regular maintenance, or perhaps applying a sealing top coat?"

Bearing in mind Tom's response above, the problem mention may be due to something other than the neatsfoot oil (e.g. fats & oils used in the tannin process). Either way, I have found Ko-Cho-Line (by appt. to HM Queen) to be a good treatment for leather that does not go moldy - it is made of "red grease" which is mineral based - you don't need much and it leaves a fairly glossy finish - intended for leather horse tack put into storage I think.

Edited November 11, 2015 by Tannin

[OLDNSLOW]

where I get my neats oil from originates in a 55 gallon drum, they then will bottle some of it in quart and gallon jugs to resell to other locals.

[spectre6000]

Might as well make the first post a doozie...

Yup. It'll go rancid just fine. Just give it time and let it breathe.

Rancidity happens when the free hydrogens in the fatty acid chains of the lipids bind with oxygen, and break off to form free fatty acids. The resulting smell depends on the length and composition of the free fatty acids. Shorter chains are more aromatic (more likely to go airborne and thus smell more), so where the double carbon bond is in the chain can change the resulting smell or lack thereof, but rancid is rancid. Neatsfoot oil is about 70% monounsaturated (oleic, palmitoleic), 18% saturated (palmitic, stearic), and 2% polyunaturated (linoleic). Fully saturated oils go rancid far more slowly than mono- or polyunsaturated oils, but free fatty acids can still be formed from UV exposure, temperature, etc. They're just less susceptible to oxidation. Nearly (nearly only because I don't claim to be an expert on all fats and oils from all sources) all natural oils/fats have some mono-/polyunsatuted content, and will eventually go rancid if exposed to oxygen, light, time, etc. Animal fats tend to be more saturated than fats from vegetable sources, but if its liquid at room temperature it is mostly unsaturated.

My guess is that the myth of neatsfoot oil not going rancid is due to it smelling nearly rancid from the start... It's also possible that the resulting free fatty acids have a longer chain (likely given the animal source), and are less aromatic than the free fatty acids resulting from the rancidification of some plant-derived oils. I would further surmise that it's the preferred oil for leather because traditionally people didn't have such a wealth of choice and used what was available, applying preference only when there was a choice to be had. People processing leather would have very likely had a ready supply of neatsfoot oil due to it coming from essentially the same source, and it certainly isn't something you'd want to eat... Just a guess based on a general understanding of history and whatnot.

Edited November 23, 2015 by spectre6000

[Norton Custom Leather]

Spectre6000, well I'm supposed to learn something everyday, if not I consider myself lazy.

Thanks for the lesson, do you craft leather also?

Oh yea, welcome to the site also.

[spectre6000]

Thanks!

I guess that depends on whether or not 'craft' has any special meaning within the leatherworking vernacular (I honestly don't know). I have used leather in the past to make things, I'm currently engaged in a leather project, and I have tools and supplies for doing so, but it's neither my primary vocation nor avocation. I used to work in the biodiesel industry (experimental feedstocks), which is where my knowledge of this sort of thing originates.

Edited November 23, 2015 by spectre6000

[Norton Custom Leather]

Leather crafting is also not my primary. Railroad Conductor first.

If you have tools & make things out of leather, your crafting.

So I would say yes for you.

A true crafter can always find a flaw in their own work, I think that is why many of us may be on here.

More so to help each other rather than find fault. Ideas outside the box.

[Big Sioux Saddlery]

"On that note - Anyone actually bought that much Neatsfoot oil at once?"

Several times. Dipping harness uses a lot of oil.

[Sceaden]

So it's normal for the a new bottle of neatsfoot oil to smell kind of rancid? I'm tempted to go to the local tandy and smell all their oil. :-P

[byggyns]

On 11/6/2015 at 1:03 PM, LeatherNerd said:

He recommended that I go with Aussie Conditioner because it was a beeswax-based conditioner; no mention if the oils in it were natural or not. (For all I know I could be rubbing beeswax and 10W40 motor oil into my leather goods.)

I looked up the MSDS for Aussie Conditioner a while ago. It is primarily petrolatum (petroleum jelly) with beeswax and other oils. It's been a while, so I can't remember what the smaller percentage ingredients were.

[Wulfing]

My grandfather gave me a recipe for a leather cream he used. Bees wax, Boiled linseed oil, Neetsfoot oil, eucalyptus oil and vodka. When warmed up and mixed together it sets as a creamy substance. I rub it in to the leather with an old tshirt after dying  then wave a hairdryer over it and buff the leather with a horse hair brush. I leave it for 24 hrs, buff again and then put resolene on top to finish.

I'm a beginner and have come up with this process through research and based on what my grandfather said. It seems to work so far but obviously I dont know what it will be like in the future. I also use it to burnish my edges. Be grateful for anyone's opinion on this method / recipe?

[SolarLeatherMachines]

http://www.livescience.com/55267-why-does-oil-go-rancid.html

[OLDNSLOW]

I think as long as you keep the bottle closed it will prolong the life of the oil, I have bought some from a local guy who gets it in 55 gallon containers and it is ok.  Now what I realized here lately is that there is 2 different types so to speak of Neats foot oil, one is the oil the other I think is called neats foot oil compound, the compound I found out gives the leather a very nice buttery look after 2 light coats.