Centroid Community CNC Support Forum

I use Dexcool which is designed for aluminum engines and other metals. Color is orange to red so looks great in clear tubing.

I also used Prestone Dexcool 50/50 premixed, it’s the same coolant I use in my airplane.

Great! Thanks!

An alternative is Water Wetter from Red Line https://www.redlineoil.com/waterwetter

I have worked in the automotive for several decades. Engine coolant is almost invariably water glycol in the ratio 50:50 or very close. It's perfectly suitable for use in all engines with cast iron, steel, aluminum, whatever. The different colourants and descriptions ("racing") are of no significance other than the price.

When it comes to the mixture ratio, the lowest freezing point is around the 50:50 mark. Pure glycol actually freezes at only -12C and water at 0C, whereas the 50:50 mix holds out until about -36C.

If you went for a non-aqueous coolant such as oil, the heat capacity will be significantly less (about 50% for most oils and dielectrics), so that's not really an option.

Most PC coolers use water, optionally with a rust inhibitor and fancy colours. There's no need to use glycol if you don't need to protect against freezing. Water is about 20% better in terms of heat capacity relative to water glycol and doesn't make a godawful mess if you spill it.

Being in Florida there's no worry about freezing.........at all, the only reason I added a cup of so of the Dexcool is for the orange color so I could actually see it in the tubing that led to the spindle. Did it make any difference in cooling or spindle longevity? I doubt it. I ran a water cooled spindle for about 2 years then switched over to air cooled spindles. No more "godawful mess" to deal with.