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

[SUP]

Why do so many people say mineral oil is bad for leather? 

Online, there are so many sites, none of which are actual chemists or experts, who go on about how bad mineral oil is for leather.

But if mineral oil is fine for baby skin, surely it is good for leather as well. Johnson's baby oil is just perfumed mineral oil and has been used for decades..

Then people say 'petrolatum ( petroleum jelly) and petroleum products are bad for leather - we would not apply it on our skin and should not on leather. Hmm. My mother used pure petroleum jelly (Vaseline) on her skin nightly as a young girl and had skin that looked barely 45 when she was 80. The beautiful skin is genetic; the lack of damage due to petroleum jelly evident. So again a myth.

How and why is it bad? Does anyone actually have an idea or scientific evidence or is it just a lot of hearsay... most started by companies selling leather care products? I searched online but all I see is more and more of the same - sites which sell leather and leather-care products talking about how everything but their product is bad for leather and  women prettily going on about their leather care cream and paste recipes, usually with oils which will surely go rancid soon enough. It is like people saying that the Romans used olive oil so it is wonderful for leather - maybe, maybe not, maybe the Romans had nothing else. and knew little more.

I rather hold judgment about mineral oil until I find some scientific evidence about why it is bad, if it is bad.  Has anyone seen any such information? or has information to the contrary?

[ScottWolf]

As to mineral oil or Parafin wax, Liquid Parrafin or any of the other names used for it in other locations, its all the same, a petroleum derived product. Mineral oil itself is not a leather conditioner like Tallow or neatsfoot, etc, it is a barrier, in that it keeps moisture in, which is why its used extensively in women's skin care products, cosmetics, etc. It can be used as a solvent in a product, as it dissolves other ingredients and is also considered a cleaning agent  as it will break down sebum  and cosmetic residue on peoples skin. For leather, its great for sealing moisture in and works best as a finishing product, after the leather has been conditioned,  and it also adds a polish or shine to the leather.

[fredk]

In my vintage car world leather straps are used to hold bonnets and boots closed, to keep spare tyres in their carriers, a lot of other places as well. Our cars spray hot and cold engine and gear box oils pretty much all over the place, over parts of the cars and passengers too. This makes it sound like we're an environmental hazard on the road but its an accumulation over time. We only use high quality mineral oil. Our engines and gearboxes cannot use the alternatives, they weren't built to do so

Since I took up leather working I looked at the car straps. The straps which get the worst of the oil are the first to rot through. In places where the oil can be washed out the straps last longer but still rot. I had to replace all the straps on my car and when I did I gave them a good feeding of NFO, and used to do it regularly. My straps have lasted 24 years now. I've noticed that others in my club are replacing their straps every 3 to 5 years

I think, the difference of using mineral oil on us is it is very highly refined and we are living. Our skin is a living organ and deals with it whereas leather is dead and just absorbs the oil and does nothing with it. Putting even highly refined engine oils on us can give us serious skin complaints - I know, I used to work on my cars without wearing gloves. Eventually I got serious dermatitis because of it

Don't take other's words as gospel truth. Try it, experiment. If something works for you, thumb your nose at the nay-sayers

[Wepster]

I can not address mineral oil, but some petro based products do destroy some types of thread. Where I used to work guys sprayed PB blaster over their work boots to "waterproof" them. Their boots generally lasted 6 mos, they fell apart. The stitching broke down.

Perhaps reaching out to a tannery with your question (and let us know) would yield more accurate results.

[Klara]

I had to go and look what the lable on my saddle/leather grease says. Sadly, nothing. The website informs me that paraffin wax is one of the ingredients, which is a petrochemical product. But I am very sure that the composition of leather grease is very different from that of motor oil. And I strongly suspect that many people say mineral oil when they think of motor oil. (And fredk's cars spray used motor oil, which is different from fresh oil).

I also have some bright blue grease for my sliding stable doors, supposedly particularly water-resistant  - I wouldn't dream of using it on leather or my skin.

On the other hand, there is famous German mineral-oil based Ballistol, which has been around for about a hundred years and is still used for everything from firearms to spinning wheels to mosquito bites (useless) and I've heard of people swallowing it as an antacid... It's not the best product for leather or wood, though, because it washes off too easily. 

Personally, I just use what I have (which is equestrian products) and don't care what "the Internet" says. Because most of that is people copying from one another. 

Edited September 19, 2023 by Klara

[TomE]

The care of vegetable tanned leather has different requirements than skin care.  The leather has been exposed to harsh extremes of pH and reactive chemicals that break down the collagen fibers then bind them together with tannins.  Oils and waxes are infused in the currying process to seal the leather and add suppleness.   Oiling and conditioning aims to add back moisture and fats/waxes without removing what was introduced during the tanning processs.  Are petroleum products OK to use?  Yes and no.  The Stohlmans mention in their Encyclopedia of Saddle Making that they made generous use of neatsfoot compound to good effect.  Neatsfoot compound is a mixture of neatsfoot oil and petroleum based oils. They also mention that pure neatsfoot oil is preferable.  Silicon oils are found in lots of leather care products including Fiebings Saddle Oil and Mink Oil.  Great for waterproofing and softening leather.  There is also too much of a good thing.  Soaking leather tack in neatsfoot oil causes the leather straps to become permanently spongey and sticky to the touch.  In my view the best products have limited ability to penetrate the leather and displace tannins, waxes, and other stuff we paid for when buying quality leather.

[SUP]

@ScottWolf I have discovered that mineral oil  makes leather shine. I was not sure of the sealing properties but that becomes icing on the cake as we use it last when getting a shine anyway.

@fredk Could motor oil have other additives perhaps that cause the damage?

@Wepster PB Blaster will surely have other additives. Could they play a role in the damage? 

As @Klara says, the composition could make a difference.

@TomE,  @fredk  - difference between living skin and preserved skin - therefore different requirements in care. Of course. But I suspect mineral oil is relatively inert on skin and only prevents surface dehydration. But it might react with chemicals in leather which has after all undergone chemical modifications. 

There are supporters and nay-sayers for every single oil online, from neatsfoot oil to mink oil, to vegetable oils.

I suspect leather deteriorating is a result of several factors including but not limited to the oils used. 

I guess it is a matter of not just what but how much, like your example of neatsfoot oil @TomE

@Wepster I believe there is a tannery around here, if I remember right, of exotic leathers. But leather anyway. 

I will inquire with them.. Put it up here as well, if I learn anything.

Thank you everybody for all this information. 

I am going ahead with making a conditioner with mineral oil - what I have is food grade. If the leather deteriorates over time, I will leave instructions in my will for that information to be put up here.

 

 

 

[TomE]

4 hours ago, SUP said:

But I suspect mineral oil is relatively inert on skin and only prevents surface dehydration. But it might react with chemicals in leather which has after all undergone chemical modifications. 

I think mineral oil is chemically inert and unlikely to react with anything in the leather.  My concern would be the solvent-like properties of any oil applied to leather and the potential for over lubricating the fibers (spongey leather) and/or the potential to displace waxes, tannins, etc.  The ideal oil would be readily absorbed so as not to remain on the surface and it would not change the temper of the leather, or do so in a controlled manner with additional applications.  For me, neatsfoot oil fills the bill.

[sheathmaker]

I have no scientific proof.....but an old very experienced saddle maker (Don Atkinson) once told me "use ONLY pure Neatsfoot Oil.  

Neatsfoot Compound contains petroleum distillates which are not good for leather."  He also used Virgin Olive Oil from time to time. I 

say again I have no scientific proof, but 99.99% of what he told and shared with me turned out to be true, so I going to continue using

just pure Neatsfoot Oil only, along with some other top dressing products like Tan-Kote and Wyosheen

Edited September 19, 2023 by sheathmaker

[SUP]

@TomE, @sheathmaker I like neatsfoot oil too and use it all the time. After all, it has stood the test of time.

The smell however, is sometimes a bit unpleasant.

It also darkens leather and I want to make a conditioner that will not do so.

Ergo, the questions about mineral oil.

 

 

[dikman]

Ballistol is basically highly refined mineral oil, what today is called pharmaceutical-grade as in baby oil, with a couple of extras added in minor amounts (mainly to make it smell nice!). It is an interesting exercise to look up the MSDS for various commercial leather-care products, many of them use the term "natural products" but then use mineral oil (I guess it depends how you define "natural" ). 

I'm guessing that for these manufacturers it's easier and cheaper to get bulk supplies of this oil than to source large quantities of neatsfoot oil, mink oil etc, plus it would be easier to get the soft consistency they want for their products. I found one product that, once I chased up the MSDS, appeared to be using hydraulic fluid, which is also a highly refined oil available in various viscosities. This, by the way, is also what is used for Lily White sewing machine oil because supposedly it doesn't stain material being sewn.

[fredk]

9 hours ago, SUP said:

Could motor oil have other additives perhaps that cause the damage?

Maybe

This is THE forum for US to experiment and check these things out. To  get to the truth. Even the tanneries will only repeat what is said by the greater un-washed

There is a discussion type which I call a circular-argument. It goes like this; I read it in a book, I put it up on an internet forum, someone else reads the forum and puts it in a magazine, I read the magazine and I know I'm right because I read it in a book and a magazine.

Thats how a lot of these myths become perpetual

I've thought of something. My Austin 7 car was built in December 1930. In its drive system is an item we call 'the donut', aka  a fabric coupling

(rear wheel drive BMW cars use something similar in looks)

I have an original one from 1929. Originals are made of laminations of heavy fabric/canvas and leather, all tightly compressed and held together by those triangular plates. I know its from 1929 as the date on manufacture is stamped on one of those plates, That was retired as the rivets on one plate set ripped out during a race. Anyway, servicing of this item was to take it off at regular mileage intervals and apply some light engine oil to it to keep it supple. Not to soak it in oil, just a small amount

I can say that when it came off a few years ago it was 87 years old and neither the leather nor canvas showed any signs of rot or deterioration.

Another; the Austin engine was fully overhauled in 1984. I did it again in 2004. Inside the engine are some oil seal gaskets made of oil impregnated leather. They are in constant saturation with the engine oil. None of those gaskets were being destroyed by the engine oil. They were changed because they were too compressed to re-use

[SUP]

@dikman exactly what I think too. Companies will go for what is cheapest. 

And Mineral oil is  obtained  fossil fuel, therefore organic or 'natural'. That is what those companies  probably mean. And fool a the majority of their consumers.

@fredk WOW! Your Austin will be a 100 soon!  Pics please, if possible of this car?

Back to topic,  You are perfectly right. Tanneries and most everyone else will parrot what is online. 

And from your experience,  engine oil does not damage leather. So mineral oil should be fine too.

@TomE's and  @sheathmaker's experiences show that neatsfoot oil, used judiciously, is also good for leather and not does not damage it.

SO mineral oil and neatsfoot oil are good possibilities for use in conditioners. Both evidently do not do any damage.

I wonder if there are any labs doing some sort of research work on the effects of other oils on leather.

Vegetable oils, I am a little concerned about. By their very nature, they are not meant to have a long life  or survive differences in temperature; how long do coconuts or avocadoes or olives survive anyway? In contrast, cattle have longer lives and are warm-bodied. I'm probably talking through my hat though. I feel there will be someone or the other telling me so, usually kindly. 

You have a good idea  @fredk  Maybe as many people as possible could talk about their experiences here, rather than hearsay off the internet, about the effects of different oils on leathers, in different conditions. A repository, so to speak.

 

 

 

 

[fredk]

7 minutes ago, SUP said:

I wonder if there are any labs doing some sort of research work on the effects of other oils on leather.

I doubt it very much. Research is money led. Only when something is affecting a big company's profits do they research & develop. No one is fussed about leather - just use the same ole thing we've used for centuries, it works, it will work, don't change it. Its not just in the leather industry but in other fields as well

11 minutes ago, SUP said:

Vegetable oils, I am a little concerned about. By their very nature, they are not meant to have a long life  or survive differences in temperature; how long do coconuts or avocadoes or olives survive anyway?

Jars of olive oil from about & over 3000 years ago exist and the oil is/was still good, In good airtight sealed containers veggie oils will last a very long time, hundreds of years. Once opened their life is in months. But NFO can go bad in time as well. Petroleum based mineral oils do not go rancid

Just, do NOT use chicken fat or grease, without refining it maybe - in my history presentation group a chap brought me his belt pouch. It was well dried out and needed NFO. But he insisted I use fresh chicken fat/grease as 'thats what they would have used in medieval times' (uh, no, they used a version of NFO) about 3 months later he brought the pouch back to me, in a sealed plastic bag. Could I clean it? The chicken fat had gone rancid and was rotting the leather. I tried to clean it but it was too far gone. Ever smell rotting chicken? its F**king awful and sickening. That pouch was burnt by the owner

34 minutes ago, SUP said:

You have a good idea  @fredk  Maybe as many people as possible could talk about their experiences here, rather than hearsay off the internet, about the effects of different oils on leathers, in different conditions. A repository, so to speak.

We'll start. When I'm out shopping next I'll get some 'Baby oil' and vaseline. I have virgin olive oil. I'm not currently working on anything that needs oiled but soon I will be

 

1 hour ago, fredk said:

There is a discussion type which I call a circular-argument. It goes like this; I read it in a book, I put it up on an internet forum, someone else reads the forum and puts it in a magazine, I read the magazine and I know I'm right because I read it in a book and a magazine.

Thats how a lot of these myths become perpetual

One other myth which is perpetuated on the internet is that 'ready rivets' are not strong. In my experience it is the opposite. Years ago when I was on facebooky, I asked a few of these peeps who said the rivets were not strong. None of them had used them. General answer was; 'I won't use them because I read they aren't strong.. . .'

 

[SUP]

@fredk unfortunately, you are right about the reasons for research. 

About the olive oil, exactly. Exposure to air.. and leather is not going to be kept air-tight! 

SO great. I will try as well. I have plenty of scraps I can use.

I have coconut oil, both fractionated and cold pressed. I know the cold pressed goes rancid fast if exposed to air. So will not use that. I know how it smells. YUCK! Will check the fractionated. Use it on veg tanned leather and keep it outside, in a warm place for a week to 10 days, reapplying if it gets too dry. Let's see what happens. Cold pressed coconut oil gets smelly in a few hours. I suspect this will too. People use fractionated coconut oil in their hair as an after wash conditioner - you can smell it from a distance.

[fredk]

55 minutes ago, SUP said:

SO great. I will try as well. I have plenty of scraps I can use.

Use it on veg tanned leather and keep it outside, in a warm place for a week to 10 days, reapplying if it gets too dry. Let's see what happens. 

Okee-doakly. I'll use some scrap as well and put it out in my spare 'drying' car

Now, both of us should try our choice of oils on some different pieces of leather.

i.e.  use oils 1, 2, 3 on leather A, and on B, and on C,, that would be 9 test pieces. 

Keep notes

Lets keep to just a few common oils. Keeps it all simpler

Conditions here are very wet and getting cold.In my spare car it will be warmer, and variable. I expect conditions for you are quite different

Edited September 20, 2023 by fredk

[TomE]

One knock against vegetable oils and olive oil is they attract rodents at least for tack stored in a barn. I would also consider lanolin as a vehicle for fats/waxes in a conditioner.
 

Aussie conditioner and Effax Leder Balsam cause very little discoloration in comparison to Bick 4 or Black Rock Leather-N-Rich in my experience. 

[Burkhardt]

3 hours ago, SUP said:

Vegetable oils, I am a little concerned about

That's all I use. My snuff holder I made about 10 years ago is only oiled with veg oil and is just fine

[Burkhardt]

7 minutes ago, TomE said:

One knock against vegetable oils and olive oil is they attract rodents at least for tack stored in a barn. I would also consider lanolin as a vehicle for fats/waxes in a conditioner.
 

Aussie conditioner and Effax Leder Balsam cause very little discoloration in comparison to Bick 4 or Black Rock Leather-N-Rich in my experience. 

To say that rodents chew on leather because of olive or veg oil is a little far fetched. They also chew on wood and just about any coated wire without any scent. Humans are on the bottom of the smelling chart and when you walk into a leather shop everyone says it smells so good without any oil added to make it smell better. I think anything new or a fresh smell will attract rodents with or without oil.

[fredk]

20 minutes ago, TomE said:

One knock against vegetable oils and olive oil is they attract rodents at least for tack stored in a barn. 

I had a big roll of leathers damaged by meeces. They got into the very centre of the roll and chewed through several layers for to make their nests. Holes the size of a woman's fist right through each hide. None of that leather had any treatment at all. And they'd pee'd on it as well     

[Wepster]

As this thread progresses, I think we should keep in mind, thread. As we condition leather products, what ever we use is also affecting the thread. I doubt olive oil would affect the stitching, but other products might, as most threads seem to be synthetic. So, perhaps these experiments should be on stitched leather (and stitched with various thread types).

Good luck. I will keep following this thread. I certainly do not have any answers.

Hmm, I wonder about the Scandinavian soap finish (used on floors and furniture) would fare on leather? Cheap, natural (depending on your definition), used on human skin. Don't know what it would add or protect from though (but it does have the word "finish" in it).

[ScottWolf]

18 hours ago, SUP said:

@ScottWolf I have discovered that mineral oil  makes leather shine. I was not sure of the sealing properties but that becomes icing on the cake as we use it last when getting a shine anyway

I am going ahead with making a conditioner with mineral oil - what I have is food grade. If the leather deteriorates over time, I will leave instructions in my will for that information to be put up here.

 

 

 

So, I would direct you to my post in the forum here that I made about an actual leather conditioner recipe and the subsequent posts in that thread that have been made since I first posted it.

CONTEXT. That is something that seems to be glossed over in threads like these in leather forums. Some people only deal in absolutes and refuse to acknowledge any differing information or they simply parrot things they have heard /read about.  For example.... " I don't use "X" ingredient because my sisters brother cousin said it goes rancid and Larry the Legendary Leather maker guy said the same thing" 

OK, lets look at this critically and put it into context, because that where an ingredient like mineral oil falls into. First off the term "rancid" is actually referring to an ingredient oxidizing and not necessarily going bad like meat or milk or any other food item turning rancid. While some ingredients can actually do just that, and this is where the context comes in, those ingredients are usually not used solely by themselves on leather, they are used in combination with other ingredients that actually retard and or prevent said ingredient from oxidizing. Natural preservatives like beeswax, Vitamin E, etc are all ingredients used in A LOT of commercially available products along with ingredients like Mineral oil, if one takes the time to read product MSDS's.

Neatsfoot oil (NFO) is actually a good example to use. Used in excess and by itself, can and will oxidize and form into hard crystals that sit and abraid in between the leather fibers and cause it to degrade over time. Not opinion, scientific fact. However, used in moderation and or combined with other ingredients, those negatives are negated and the item will likely wear out before those negative effects occur or are ever seen. Neatsfoot compound is something I've not seen recommended in leather forums for some time, as it's typically made for use on machinery as it does have a higher concentration of petroleum ingredients and other undeclared ingredients in it that can be harmful to threads, etc. To further put things into perspective, LEXOL is a popular product used by some but it is simply Neatsfoot oil if you look at the MSDS. The interesting part is that it is 80% water, 5-10% NFO and the remaining ingredients are preservatives/stabilizers that keep an oil and water from separating from one another. So in reality, very little NFO is actually being applied to a piece of leather when products like Lexol or other NFO based products are being used. The same holds true for products that have mineral oil or a petroleum based ingredient in its mixture. 

As I stated in my initial post, mineral oil  forms a barrier and isn't actually absorbed into the leather like an actual conditioner ingredient would be. So it's a really poor leather conditioner compared to other ingredients commonly used in commercial products like Tallow, coconut oil,avocado oil, almond oil, etc. However, it is useful in sealing in moisture and oils that those other ingredients are known for and adding a shine. This, combined with those natural or man made preservatives and used in moderation in the ratio of ingredients is why you find a good deal of commercial products have a mineral oil/petroleum based ingredient in them (not all obviously).

 

Like many things, if used in moderation and not strictly by itself, but with other ingredients/preservatives, mineral oil as one of several ingredients in a product is not going to prove detrimental to the life of the leather itself.

 

Edited September 20, 2023 by ScottWolf

[kgg]

On 9/19/2023 at 4:11 AM, SUP said:

Why do so many people say mineral oil is bad for leather? 

What I do for my work boots and I'm no expert is I use 100 percent JOJOBA cold pressed oil and white food grade mineral oil. I rub about two ounces of JOJOBA oil per work boot oil into the leather and let it get absorbed then I apply about six ounces of mineral oil in and let the boots sit overnight. Seems to work at making the boots water resistant, softens the leather and seems to add back some moisture into the leather. The downside is that the tan colored leather will be darken but for a work boot I don't mind. The JOJOBA oil is probably the closest thing to sperm whale oil.

kgg

[SUP]

@ScottWolf that is exactly the point @fredk made earlier, that people blindly repeat  what they have heard, not necessarily from  their own experience. If you wants to hear the actual voice of experience, you need to have worked with leather for years and remember what was used, several decades later, to know what was or was not detrimental to it, and there are so many other factors that can damage the leather as well. I, for one, am too new to leatherwork and will be long dead and gone before many decades have gone by. Ergo my comment about instructions in my will.

It is not a matter of refusing to acknowledge information as much as the widely present views of today - " I saw it online, so many people online said it, so it must be true. Even if you say different, so many online say so, so I believe them'.

About oils turning rancid, it is the smell or texture that is unpleasant most often.  Besides I do not know what the products of those oxidative processes are and they may affect the leather, or not. 

Additives will retard or prevent the oxidation of oils but then, you have to have the correct proportions of the additives for preservation, else it is pointless. That becomes another chemistry experiment. 

I should think anything used in excess would cause some issue or the other, excessive softness or even remaining on the surface causing greasiness. 

Like you said, most commercial products, if you read the MSDS, contain many of these oils and waxes . I have been reading them up when researching leather conditioner recipes.  It is a little amusing when people refuse to use neatsfoot oil or mineral oil or petroleum products and then swear by products with these very ingredients. 

 One thing I have noticed is, when people say that leather deteriorated, it is often the threads which rotted away.  Natural fibres deteriorate faster than leather, naturally. That happens even in ordinary cotton clothes with cotton or linen thread. Cotton and linen themselves deteriorate over time. I wear a lot of cotton and some of my favorites are not usable 20 years later. That is all the time it it takes.  No one uses any oils on ordinary clothes!

Leather itself falls apart sometimes but I suspect that is because of excessive oils or the way it is used.

Not knowing what causes the damage, the easiest to blame is the oils used. Commercial companies with ulterior motives push this further and a myth is born.

To debunk this, our experiments with leather might help just a little. Putting in a few stitches with  cotton and synthetic threads is a good idea. 

@kgg  that is good information about jojoba oil. It is said to have a composition similar to skin oils. You are talking from personal experience.

@Burkhardt which vegetable oil do you use?

I hope others join @fredk and me in this experiment, using oils  and scraps they have at hand. 

 

 

About mice. Please don't remind me. My cat caught one and placed it behind me on the sofa. It fell behind the cushions and I found it a while later while cleaning. It has nearly petrified within a few months. Evidently in that place it was deprived of air. Not a pleasant experience.

Mice will eat anything and are smart too, and cute. I always hear people squealing about their cuteness - does not deter from their unpleasant pee and stealing and chewing habits!

I believe the smell of cloves deters them.. No idea if that is true and I do not  I want my leathers to smell of it.

Edited September 20, 2023 by SUP
Correction of errors.

[SUP]

The deterioration of leather and the thread happens over time. I I will apply the oils on the leathers and keep them somewhere safe, and check through the months, with periodic updates if there is damage. @fredk what do you think?

 

Incidentally, does anyone have natural fibre threads that have deteriorated without use? I know my regular stitching thread does so, and I have no reason to expect otherwise from thread used for leatherwork.