Bob La Londe fired this volley in news:im8650$t0d
:

Because the manufacturer of the Metal Nibbler One says, "ABSOLUTELY DO
NOT USE WATER BASED COOLANT ON THIS MILL." Aluminum is a very reactive
metal and the majority of this machine is aluminum. (Metal Nibbler Two
is about 95% aluminum.)


That would indicate an ignorance on their part of what's available in
water-based coolants today.

I know some little bit about the reactivity of aluminum (being in the
pyrotechnics business). Its reactions with water are a matter of
constant attention in my line.

Simply by adjusting the pH of an otherwise non-corrosive water solution
with a suitable buffer, one can reduce the reaction potential to nil.
Most modern coolants contain such buffers, and are specifically designed
for certain metals. Many are designed not only to not injure, but
specifically to benefit the life and surfaces of aluminum parts.

I'd add that if a mill is designed to suck water up into the motor during
use, it's badly (no, I'll say stupidly and negligently) designed.

I will research this "Metal Nibbler" thing. I want to know what to
avoid.

LLoyd