Mist coolant?

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lesrhorer

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I have a couple of mist coolers for my lathe and my mill, and I want some recommendations for coolants to use. I have used water-soluble oils in the past, but I am not all that fond of them. They do tend to be fairly inexpensive, but the fact is they can promote rusting, especially in areas that are hard to reach. Of course, a good spray of a penetrating oil like WD-40 after one is finished machining can do a good job of driving the water out and preventing rust, but I was thinking, "Why not just use WD-40 instead of a water-soluble oil in the first place?" Depending on the oil / water mix, I can get WD-40 for about the same cost as water-soluble oil. Is there some reason why one shouldn't use an undiluted penetrating oil as a mist coolant? Is there an inexpensive volatile solvent that might be good to dilute the penetrating oil? Is there a less expensive penetrating oil than WD-40 that might work well? What about kerosene, or maybe JP-7?
 
lesrhorer said:
I have a couple of mist coolers for my lathe and my mill, and I want some recommendations for coolants to use. I have used water-soluble oils in the past, but I am not all that fond of them. They do tend to be fairly inexpensive, but the fact is they can promote rusting, especially in areas that are hard to reach. Of course, a good spray of a penetrating oil like WD-40 after one is finished machining can do a good job of driving the water out and preventing rust, but I was thinking, "Why not just use WD-40 instead of a water-soluble oil in the first place?" Depending on the oil / water mix, I can get WD-40 for about the same cost as water-soluble oil. Is there some reason why one shouldn't use an undiluted penetrating oil as a mist coolant? Is there an inexpensive volatile solvent that might be good to dilute the penetrating oil? Is there a less expensive penetrating oil than WD-40 that might work well? What about kerosene, or maybe JP-7?
Click to expand...
Water soluble DOES NOT promote rust.......
 
benmychree said:
Kerosene stinks and the mist may be flameable.
Click to expand...
I rather like the smell of kerosene.

Yes, of course it is flameable. It would make a nice little flame thrower, although JP-7 isn't very flameable. There aren't any open flames in my shop, however. Without an ignition source, no flames.
 
Jim F said:
Water soluble DOES NOT promote rust.......
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I know that is the claim, but I am a bit skeptical.

OK, so let's assume it is true I needn't worry about rust with a good water soluble oil mixed at a proper water / oil ratio.. 'Back to my main point. Is there a superior water soluble solution that is less expensive than WD-40? Of course, going with a more dilute oil / water ratio will reduce the cost considerably, but most I have seen call for roughly 1:1.
 
It all depends on the material you are machining. I use denatured alcohol in my Fogbuster for aluminum, water soluble coolant for ferrous materials.
 
I use Kool-Mist brand, mixed per the instructions. I've not had any rust issues.

We use several types of water soluble oil at work... in 25 years, I've never seen any rust on the machines.

-Bear
 
99% Isopropyl Alcohol. More droplets than mist.

​

 
682bear said:
I use Kool-Mist brand, mixed per the instructions. I've not had any rust issues.
-Bear
Click to expand...
Same here.

+1 and no rust. per instructions, I mix 32 parts water to 1 part Kool-Mist 77, so 1 gallons of concentrate = about
$45 USD. and so 1 gallon diluted into usable form cost $1.40 USD and I can mill for hours and hours on a gallon in my dual sprayer Mist-Buster system. I summary: Cheap and Effective.
 
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