What are the ingredients in water-based machining coolants? Can they be homemade?

Will it cause rust problems if the liquids are kept in the pan under the machine too long?

Info appreciated.

Water-based machine coolants are normally either a semi-synthetic or full-synthetic, and most have a rust inhibitor in them, which works quite well.
I don't think you're going to come up with a homemade concoction that will probably work, but who knows.

We use TRIM E206, and we purchase it through J&L industrial for $85.25 for 5 gallons. You mix up about a quart of coolant for 5 gallons of water. You can increase this a little if you begin to have rust problems, but don't overdue it, because it will not cut as well with a heavier mixture. This is a semi-synthetic that has an oil additive, but the specific makeup of it, I'm not sure. It does work better than anything we ever used in the past, and believe me, we've tried a lot of them. It has great rust preventatives in it as well, and would not rust out your coolant tank under a machine.

Hexavalent chromium (Chromium 6) can be added to water as a corrosion inhibitor, but it causes serious physical problems if it gets in your body.

Hexavalent chrome....isn't that the bad stuff in water in the Erin Brokovich movie?

Pyrotek,
I am glad you started this thread.

I put a surplus .308 Parker Hale Mauser barrel in the lathe to cut it down to be a Tokarev pistol barrel.

I called my brother the machinist and asked when should I use the cutting oil and when the coolant. He says use the coolant for everything but reaming. He says to mix it, put 3/8" coolant in a 5 gal bucket and fill up the rest of the way with water.

I put 3/8" of coolant in a plastic house plant spray bottle and fill the rest of the way with water.

I sprayed coolant instead of the messy cutting oil that flings on me and the walls and makes me stink.

No rust on the lathe or on the barrel, good stuff.


[ 07-07-2003, 23:28: Message edited by: Clark ]

Clark, glad you mentioned your project.

I was thinking what to do with my throat worn, but mostly good and thick Parker-Hale .308 barrel. Never thought about turning it into a handgun barrel. Coincidentally, I too have a Tokarev pistol.

Is the barrel link lug going to be a weld-on? Let me know how you are doing it so I can copy your idea

I want to build one with a integral compensator.....fun fun fun!

I thought for a while that the throat was shot out and that was why I paid less than everyone else [$34 each delivered].

But I kept cleaning for weeks, and the throat got better.

This has happened to me before, I cannot tell pits from dirt sometimes in a barrel.