I am in the process of doing a test mixing antifreeze with the water that saturates my JET Slow Speed Grinder stone wheel. I keep getting email on this and nobody seems to know much about it though many are more than willing to theorize.
I decided to give it a whirl and right now my JET stone grinding wheel is saturated with a 50% mixture of water and Sierra brand antifreeze. This brand claims to be "safer" for people and animals yet shows remarkable freeze protection down to temperatures that really should be off of the woodworking scale of probability.
So far the wheel has been saturated and re saturated with the antifreeze/water solution and nothing has happened to the stone. It still grinds fine, hasn't gone soft and despite being set directly in front of a hole in the garage door in my unheated shop, hasn't been bothered by temperatures (measured at the grinding wheel) of 18-degrees so far.
If anyone has tried this and has first hand information I'd like to hear it! Email me at thintz@newwoodworker.com.