I'm at the 101 level on coolant, but have been doing a lot of research on the topic. It seems that the paint on the Tormach base and chip tray is not as tough as the paint on the machine itself. This doesn't appear to be limited to Tormach, as I've seen similar threads for other machines also. The coolant tends to soften the paint. I've done a lot of research on the topic and will try some of the coolants that were mentioned specifically or being easy on the paint. On my particular machine, the paint is perfect, but the chip trays are bubbling and peeling.
Again, this info is coming only from what I've read, but some folks experience issues with mist coolant causing lung & eye irritation and also coating things in the shop. I have no experience with it, but just thought I'd mention it as a possible discussion point.
Eric
Just to let you know, I read a good deal about the lung/eye irritant issues before trying mist. You should do your own reading of course but, I decided it was a vast improvement over the alternatives.
Some of the issues I discovered are:
1) Some people were running traditional coolants in their mist systems -and this NOT what should be done. They were indeed getting eye/lung problems from misusing a product. Mist coolants are different than traditional liquid coolants -although they are the same green/blue color.
2) The ingredients in KoolMist (for example) are a synthetic version of citric acid (used as a preservative) and an extremely small percentage of a synthetic lubricant. I used to apply cutting oils on my work pieces and there is NO doubt in my mind, the smoke and skin contamination from that is 1000% worse than proper kool-mist. 1oz of stock kool mist makes about 1 quart of working solution. The dilution is extremely high and physical contact is very low. All of my sinus related problems from breathing smoke burn-off have gone away since switching to mist. Because the vast majority of mist evaporates on-contact with the part, the amount exposed to your skin is trivial.
3) Several hours of continuous kool-misting uses-up about 2-3 ounces of working solution. As far as raising the humidity of the working area... I sweat way more than that and suspect bodily perspiration is probably 2-3 times more likely to raise the environment humidity. The morning blast of humidity from puddles of wet coolant was far worse.
I'm just passing my own experiences and everyone should do their own homework... Personally though, I wouldn't switch back to wet or oil for all the money in the world.
As with ALL coolants, at the end of the day, you need to wipe-down with an oil rag and give a spritz of light oil (WD-40 etc) to prevent staining or surface rust. After all, these solutions are 99.9+% water.
I wasn't aware that coolants could soften paint. I have had no sign of this but, I just don't give a darn what a machine looks like, as long as it cuts... -Again, my personal preference...
Ray
EDIT: Fixed a broken sentence. Clarified wipe-down at end of day.