More adventures in water-based cutting juice

[bilquest]

I've been trying to figure out how to make a non-toxic, cheap, water-based saw coolant for my trim saws. Having used Lube Cool (foams) and Smokeys EZ-cut (not much different from plain water) ... I was thinking, how difficult could this be to go the 'Martha Stewart' route and mix a few kitchen chemicals? The juice I would need to concoct would be water soluble, lubricating, corrosion inhibiting, and the used stuff could be used for watering the garden/grass. Or at worst, dispose down the drain.

After days of research (i.e. Googling combo's of words) I landed on a suspect... propylene glycol. AKA, the stuff you RV owners dump in your water systems to keep from freezing while in storage. I found a gallon at the Walmart for a whole $2.48, certainly within my affordability zone. The more I read about it, the more it seemed to fit the bill. Non-toxic, by definition is a lubricant, and also inhibits corrosion. Note that this isn't the same anti-freeze you put in your engine... that is ethylene glycol, and is very toxic.

The stuff I purchased was bright pink in color and smelled like NyQuil. I dipped my fingers in the juice and was encouraged by how slick it felt. Being a cheapskate I determined to stretch my 2.48 even further. I cut it 4:1 with water before loading up the 10" saw tank.

I started cutting a few different hardnesses of stone. It seemed to cut as usual, odor was minimal, and there was no foaming. The blade seemed to be running cool and I kept topping off the tank as needed. I cut for several hours with no irritation to my skin. The only downside I encountered was blade wear and glazing when I cut the hard stuff (pastelite/agate).

Returning to Google for my follow-up consultation I discovered that blade glaze is an over-heating of the blade at point of contact, not entirely obvious when cutting. My conclusion is that while the solution feels slick, it isn't functioning well as a diamond saw lubricant. Note that it worked well in other areas. My saw isn't corroding, nor am I breaking out in necrotic warts where my hands bathed in the solution for hours. I would call the experiment a partial success.

So, now for the crowd sourcing... what ingredient could I add to the juice to get the lubricating effect that the blade needs? Remember, it needs to be non-toxic and water-soluble. Google suggested KY jelly, but I think that's for a different kind of friction. :)

I'll be the human guinea pig and report back on any sane suggestions.

[Ranger_Dave]

I add some borax. No foaming problem that I've encountered. Inhibits rust, but then I drain, dry, and WD40 my saw after each use. The water feels pretty slick.

[slabbercabber]

I use borax and sodium nitrite.  The borax acts as a surfactant and a very mild corrosion inhibitor.  The sodium nitrite is a lubricant and potent corrosion inhibitor.  I leave water in the tank until it evaporates with no ill effects.  I managed to save a bucket of sodium nitrite from our heat treat process but you can get it at the grocery store as food preservative.  It doesn't get any safer than that.

[kennyg]

Go to a Napa store and ask for water soluble  cutting oil I mix at 10:1 and have gone to as much as 20:1 with good results. It works out to about 3$/gal and if you buy 5 gal. still cheaper it contains rust and corrosion inhibitors no misting. I have been using it for several years.I am also a machinist and this i an all around oil for cutting grinding drilling etc.

[light house jack]

As to RV anti freeze as a coolant, I have an engineer in my classes who uses it. If you go to Wal-Mart, he says that the Prestone Brand  has an additive which makes it better than the Wal Mart brand.

[slabbercabber]

Soluble oil isn't real bad but we had a few cases of rash in our machine shop from its use.  This is an excerpt from the MSDS.
Skin contact
Wash off with plenty of water. Remove and isolate contaminated clothing and shoes. Get medical
attention if irritation develops and persists. Wash contaminated clothing before reuse.
Eye contact
Rinse immediately with plenty of water, also under the eyelids. Remove contact lenses, if present
and easy to do. Get medical attention if irritation develops and persists.
Ingestion
Rinse mouth. Drink 1 or 2 glasses of water. Do not induce vomiting without advice from poison
control center. Never give anything by mouth to a victim who is unconscious or is having
convulsions. Get medical attention if symptoms occur. If ingestion of a large amount does occur,
call a poison control center immediately.
  Our machinists were advised to wear latex gloves if they were in regular contact.

[light house jack]

The most skin friendly oil that you can use is food grade mineral oil. Same as baby oil. I buy mine in 5 gal. buckets from industrial oil suppliers who I find in the yellow pages.  Buying several buckets they usually will deliver.  I am told that this same oil is available at Tractor Supply as an animal laxative.  The industrial oil that I buy goes by the name of white oil or technical white oil.  When I  don't want to filter it and reuse, my plants don't seem to mind at all.

[bilquest]

Thanks for all the suggestions!

Note that I use mineral oil in my slab saw and am very satisfied with the results. However, the trim saw is a different matter in that I usually end up showered in whatever coolant is being used.

I would like to try the sodium nitrite/borax mix... could you (Slabbercabber) please post your recipe? How much of each per gallon?

[slabbercabber]

I just use what feels good.  If I had to measure I would guess 1/2 ounce of each per gallon.

[55fossil]

       I just use water... but I built some shields to help keep me dry. My health is bad enough so having to wonder about what I am breathing or putting my hands in is out of the question now. Sooo, think about this. I purchased a Lortone basic saw and added the motor and put it on a simple base. If you buy a TS-10 which is the 10 inch trim saw it is $370 plus shipping. So call it $400. If you use it for 40 months with water and had to replace it that is 10 dollars a month. Probably less than many people spend on oils and such. I have used my Lortone 6 inch trim saw with plain water for over 5 years and still runs like a top. So I am under 5 dollars a month and no worries. I do clean and dry it each day after I am done.
    I will try and add some pictures of the shields I made later today.