Type of Oil for an Oil Stone

[Robert Delhommer Sr]

I buy cheap store brand mineral oil at the dollar stores for that.

[Glen Canaday]

I've been using straight mineral oil for a while now, too.

To answer a question above, yeah the stuff sold as "intestinal lubricant." It's straight oil without additives.

[Stew Denton]

Hi All,

A couple of thoughts on the toxicity of some of the fluids mentioned above.

"Mineral Oil", as sold at the drug store and grocery store, for internal use is very much non-toxic. It is specially treated oil that has the bad actor chemical compounds either removed by chemical processes or chemically reacted away to convert bad actors into benign compounds. This is done in various ways, chemically, but the bottom line is that this stuff is highly refined and treated. It is also thoroughly tested to insure that the bad actors are at such low levels that the material is safe for use.

On the other hand, this is not the case for "mineral spirits." "Mineral Spirits" does not have the special treatment described above for the human use mineral oils. That said, not all mineral spirits are created equal. Some, which are sometimes labelled "odorless mineral spirits" are much less toxic than the ordinary material. This is the case, because in order to get the odor level down, they do treatments which react away or remove most of the odorous compounds, and this same treatment also removes some of the bad actor compounds, but this not to the extent that it is done to "Mineral Oil" for human use.

Things like gasoline, kerosene or diesel, on the other hand, have lots of bad actor compounds present. Some of the compounds present in such materials are toxic and others cause cancer. These products are made to be fuels, not to be used in a way that causes skin contact or causes the vapors to be inhaled. I know people have used such materials for years in parts washers for mechanic work, etc.

However, I also know that folks who have used such for parts washing, and had to totally give up working with such materials for the rest of their lives, or they were going to die well before their time, a very close friend of mine actually knew one such individual that had such medical instructions given to him after a medical situation. He had to completely give up working with these solvents or face death or disability. This is rare, but it does happen.

For the above reasons, I recommend that you either buy mineral oil, cooking oil, baby oil, any such product made for human consumption, or any of the commercially made sharpening oils. They aren't that expensive and they are drastically safer to use. (Cooking oils can go rancid or gum up, etc., so these aren't on my list of ones that I personally use, but they are safe and if you have good results with them, then go for them.)

I do not recommend the use of gasoline, diesel, or mineral spirits, or any other similar material. These and other similar products are too toxic or cancer causing to be safely used for any such use where you are close enough to breather the fumes.

I know some of you may have opinions that differ from the above, and I do not wish to offend. However, I have done specialized analysis of, tested, done specialized chemical research on, developed and help develop, evaluated competitive products for marketing folks, fractionally distilled, done specialized treatment of, etc., etc., etc., of: solvents, very high tech fuels, refinery streams, etc. for better than a quarter of a century, so know of what I speak.

Stew

[Stanley Covington]

Hi All,

A couple of thoughts on the toxicity of some of the fluids mentioned above.

"Mineral Oil", as sold at the drug store and grocery store, for internal use is very much non-toxic. It is specially treated oil that has the bad actor chemical compounds either removed by chemical processes or chemically reacted away to convert bad actors into benign compounds. This is done in various ways, chemically, but the bottom line is that this stuff is highly refined and treated. It is also thoroughly tested to insure that the bad actors are at such low levels that the material is safe for use.

On the other hand, this is not the case for "mineral spirits." "Mineral Spirits" does not have the special treatment described above for the human use mineral oils. That said, not all mineral spirits are created equal. Some, which are sometimes labelled "odorless mineral spirits" are much less toxic than the ordinary material. This is the case, because in order to get the odor level down, they do treatments which react away or remove most of the odorous compounds, and this same treatment also removes some of the bad actor compounds, but this not to the extent that it is done to "Mineral Oil" for human use.

Things like gasoline, kerosene or diesel, on the other hand, have lots of bad actor compounds present. Some of the compounds present in such materials are toxic and others cause cancer. These products are made to be fuels, not to be used in a way that causes skin contact or causes the vapors to be inhaled. I know people have used such materials for years in parts washers for mechanic work, etc.

However, I also know that folks who have used such for parts washing, and had to totally give up working with such materials for the rest of their lives, or they were going to die well before their time, a very close friend of mine actually knew one such individual that had such medical instructions given to him after a medical situation. He had to completely give up working with these solvents or face death or disability. This is rare, but it does happen.

For the above reasons, I recommend that you either buy mineral oil, cooking oil, baby oil, any such product made for human consumption, or any of the commercially made sharpening oils. They aren't that expensive and they are drastically safer to use. (Cooking oils can go rancid or gum up, etc., so these aren't on my list of ones that I personally use, but they are safe and if you have good results with them, then go for them.)

I do not recommend the use of gasoline, diesel, or mineral spirits, or any other similar material. These and other similar products are too toxic or cancer causing to be safely used for any such use where you are close enough to breather the fumes.

I know some of you may have opinions that differ from the above, and I do not wish to offend. However, I have done specialized analysis of, tested, done specialized chemical research on, developed and help develop, evaluated competitive products for marketing folks, fractionally distilled, done specialized treatment of, etc., etc., etc., of: solvents, very high tech fuels, refinery streams, etc. for better than a quarter of a century, so know of what I speak.

Stew

Stew

Thank you very very much for the professional insight!

I have recently read warnings about the long term health impacts of mineral oil as it is used in the makeup industry. Are you familiar with these results, and do you credit them?

What is your take on the toxicity of WD-40?

Once again, as a cancer survivor I thank you for sharing your insight.

Stan

[Patrick Chase]

I have a Norton oil stone (well 3) and am wondering what type of oil should be used. Thanks.

I use food-grade white mineral oil for oilstones. You can get it on Amazon or from a drug store as Jim says.

The one place I don't use mineral oil is for lapping with fine grit SiC, as it's fiarly viscous and forms a thicker surface layer than is ideal for fine abrasives. I use a thin oil-based diamond extender that I already have on hand for that, though odorless mineral spirits or kerosene would probably also work nicely.

[Patrick Chase]

When I was a kid, I can recall my Dad using - of all things - vegetable oil, the same stuff Mom put on salad.
Now Dad was just sharpening her knives at the kitchen table, but still, it seemed to get the job done well enough.
I dont know how he cleaned the stone afterward, but it never smelled rancid.

Vegetable oils polymerize and dry to a solid layer of gunk after prolonged exposure to air. Mineral-based oils (white mineral oil, kerosene, mineral spirits, etc) stay liquid.

[Patrick Chase]

Problem with oils per se is that they are quite frequently toxic. And really, do you need a petroleum product for sharpening? Sharpening is the controlled use of abrasion, and is not made more efficient with lubricants.

Water works fine on oilstones, especially with a bit of dishwashing soap added to help float away swarth. Use distilled water sans chlorine, and add a bit of washing soda or diluted caustic soda to change the PH, and rust will never be a problem. Cheaper than anything in a can.

For a lot more money, you can buy non-toxic water-based cutting fluids from a machine tool supply house. These products are ideal for sharpening, far better than any plant or mineral-based lubricant.

Stan

White mineral oil is used as a laxative. It isn't harmful unless you vomit it up and then aspirate it into your lungs.

The lighter distillates are a bit less friendly but even so you can get pretty benign stuff inexpensively.

[steven c newman]

About all I use on my oil stones is just plain old 3in1 oil. works for me....

Anyone here just soak their stones until they don't soak any more in? Haven't on mine...yet.

[Patrick Chase]

Stew

Thank you very very much for the professional insight!

I have recently read warnings about the long term health impacts of mineral oil as it is used in the makeup industry. Are you familiar with these results, and do you credit them?

What is your take on the toxicity of WD-40?

Once again, as a cancer survivor I thank you for sharing your insight.

Stan

I don't think there's sufficient data on those risks. The objective claim I've seen is that some (unspecified) "cosmetic grade" mineral oils contain more aromatics than the regulators assumed. It's going to take a while to see how valid that concern is, and if so how more accurate information would change the safety assessment. Stew might be able to add more.

This sort of thing comes down to risk a question of risk-management approach, and different people will prefer different tradeoffs. Speaking only for myself, my general approach is to:

1. Try to use chemicals that have been in wide use for a long time and aren't known to contain strong/proven carcinogens or toxins.

2. Limit my exposure as much as reasonably possible while still getting the job done.

In other words, take "reasonable" measures in both respects without overdoing either. The rationale is that if something old and ubiquitous like mineral oil does have a hazard that's escaped notice for this long, then it's probably a pretty low-severity one such that exposure limitation will reduce overall risk to acceptable levels. The problem of course is that "acceptable" is subjective and individual, and I can certainly understand why Stanley's threshold might be different from mine.

The other thing to think about is the possibility of running from a known, low risk to an unknown one that's as bad or worse. One classic example is the recent reaction to BPA. BPA presents a risk at higher concentrations (the fact that it "mimics" female sex hormones is pretty well documented, but so far most regulators have decided that current levels in food packaging are acceptable for all but infants) but there's now emerging evidence that the replacement plasticizers are just as bad. IMO the smart move there is to limit exposure to whatever's in plastic containers, where doing so doesn't introduce other risks.

[Stew Denton]

Hi All,

Stanley, no I am not aware of the warnings on the use of Mineral Oil in cosmetics, but that certainly does not mean that such warnings do not exist, and such may even be valid, I don't know. I do know from long experience in subjects that I am very knowledgeable about, that I am not very trusting of popular media on a lot of issues involving the safety of various chemicals, etc.

I will add, however, that there is a big difference in the hazards of products used in cosmetics that women put on their skin for several hours a day for 40 or 50 years, and a fluid wood workers occasionally use to sharpen tools with for short periods of time. For the short time a wood worker is exposed to such things as mineral oil when sharpening, I believe that the risk is extremely minimal, as such products are about as safe as you can make a hydrocarbon fluid.

With regard to WD-40, it again, is not a product that is designed to be used with human skin exposure. It is not treated to remove bad actors, to my knowledge, and I would only use it for it's intended use, not for sharpening.

Your comments on using water based honing fluids on oil stones was quite interesting, and if effective, should be quite safe. I would be quite leery of using anything stronger than sodium bicarbonate to adjust the pH with, however, as stronger bases are very hazardous if you would get a small droplet in an eye. In your situation as a cancer survivor, however, you probably should avoid some chemical exposures that are not very hazardous to the rest of us. You would know more about such, however, than I do.

Patrick's comment that there is information that certain "cosmetic grade" mineral oils contain more aromatics than has been thought could certainly explain some of the warnings on cosmetic products containing mineral oil that Stanley has mentioned.

In our industry we have to compete with Chinese products, and I am extremely leery of the quality of such materials. If a cosmetic contains mineral oil from China, such could explain the warnings and also the idea that the mineral oil could have more aromatics than are expected. Generally speaking, the standards of such materials made in the US are high enough and American companies have to be so careful, that I would not be worried about human use mineral oils made here. We regularly test some of our products for aromatic content down to very low parts per million levels.

I think Patrick's comments are a good "common sense" approach, and I take a very similar approach.

One comment is that we learn more about hazards and safety concerns as time passes, and we don't do things in the lab now that were common practice when I was in school. So, it is possible that we will learn of hazards that no one currently knows about......BUT, as Patrick mentioned, human use mineral oil has been around so long, and is used so extensively that I am convinced that it is very safe material for use in sharpening.

For me, the bottom line is that I don't want to take unnecessary exposures to toxic and cancer causing compounds by using products that contain high levels of such for sharpening. I have worked with VERY VERY dangerous compounds over the years, and don't want to be exposed to things that years ago we were far less careful with than we are today.

It doesn't matter to me if someone has a magic mixture of kerosene, WD-40, and small amounts of smooth peanut butter that cuts 50% faster than commercial honing oil or human use mineral oil, I am not going to use it. I will stick with commercial honing oil, human use mineral oil, and other such safer products. Some folks want to think about saving a few bucks by using Diesel or similar materials in their sharpening, but the cost difference between Diesel and commercial honing oil or mineral oil, for even a few years of sharpening, is less than what you pay for even a single good vintage Stanley plane iron on Ebay.

Very Bottom Line: my advise is stick with the safer products, and avoid the more hazardous stuff.

Stew

[bridger berdel]

Isopropyl rubbing alcohol in a spray bottle. It's intended for use on human skin, so I'm assuming that it won't cause problems. It doesn't promote rust. It's a bit thin for porous stones, but great for diamond stones and arkansas stones.

[Patrick Chase]

Isopropyl rubbing alcohol in a spray bottle. It's intended for use on human skin, so I'm assuming that it won't cause problems. It doesn't promote rust. It's a bit thin for porous stones, but great for diamond stones and arkansas stones.

A 50-50 mix of alcohol and water works great for diamond stones. It's more common to use denatured alcohol (mostly ethanol) rather than isopropanol due to ethanol's lower volatility though.

[steven c newman]

From making rubber hose for over 22 years as a Compounder, Mixer operator......I have way more health concerns than what is in my oil stones. Already had the COPD before I ever used an oil stone. Seemed people that worked there longer than me( 26 years seems to be the cut-off point) are mostly......buried. I might even have as much oil behind my ears, as I put on the stones. What was the ad? "A little dab will do ya" All things in moderation.

[Stanley Covington]

Hi All,
Your comments on using water based honing fluids on oil stones was quite interesting, and if effective, should be quite safe. I would be quite leery of using anything stronger than sodium bicarbonate to adjust the pH with, however, as stronger bases are very hazardous if you would get a small droplet in an eye. In your situation as a cancer survivor, however, you probably should avoid some chemical exposures that are not very hazardous to the rest of us. You would know more about such, however, than I do.

In our industry we have to compete with Chinese products, and I am extremely leery of the quality of such materials. If a cosmetic contains mineral oil from China, such could explain the warnings and also the idea that the mineral oil could have more aromatics than are expected. Generally speaking, the standards of such materials made in the US are high enough and American companies have to be so careful, that I would not be worried about human use mineral oils made here. We regularly test some of our products for aromatic content down to very low parts per million levels.

Very Bottom Line: my advise is stick with the safer products, and avoid the more hazardous stuff.

Stew

Thanks to both Stew and Patrick for your insight. Not being a chemist, nor in the industry, it is a relief to hear the thoughts of people that are.

When I was a young man working construction, we used many nasty, highly toxic chemicals for cleaning, prepping, stripping, and painting without any skin protection or respirators. I am convinced I later paid the price for my lack of knowledge on the surgical operating table. I am more careful nowadays about the chemicals I allow to come into contact with my skin and lungs.

I am convinced that water is the best liquid for sharpening, and I came to this decision after spending many hours watching and questioning, and many tens of thousands of dollars of other people's money on the services of, professional sword sharpeners (polishers) in Japan. Water meets all the requirements for sharpening, with the only disadvantage being that it promotes rust. Tapwater especially is bad since it ALWAYS contains chlorine. The sword polishers in Japan overcome this defect by adding a bit of very dilute caustic soda sold as a cleaning chemical, which is indeed hazardous until diluted. An alternative is washing soda (sodium carbonate) which can be found at most grocery stores in the laundry detergent aisle, and is totally safe. Sword polishers have wet hands and feet all day (yes, feet), and would die quickly if they used hazardous materials.

For waterstones, I mix distilled water (no chlorine) with washing soda and store it in a plastic dishwashing soap bottle. When using novaculite stones, I add a drop of dishwashing soap to help float away the swarth. Easy peezy.

As I mentioned in my previous post, in my opinion, it makes no sense to use a liquid, such as an oil, that actually reduces friction since I want to wear away the blade's metal on the stone, not preserve it. Besides, oil and commercial honing fluids are relatively expensive, but more importantly, are messy and a pain to clean.

Stan

[Kees Heiden]

As I mentioned in my previous post, in my opinion, it makes no sense to use a liquid, such as an oil, that actually reduces friction since I want to wear away the blade's metal on the stone, not preserve it. Besides, oil and commercial honing fluids are relatively expensive, but more importantly, are messy and a pain to clean.

Stan

That's funny, I switched to oilstones partly because of the stupid mess the waterstones always make.
And indeed water is cheaper but you need so little oil that the cost is insignificant. And it sure doesn't seem to hinder the abrassive action of the stone. I guess the pressure on the tool is high enough to push aside the oil.