Coolant Freezing in Spindle - Advice?

Hey Folks,

Last summer, I built a CNC router.

I had to go away to college earlier in the year. I had left my coolant in the tank and figured it would be fine staying there (distilled water with a few cups of antifreeze) as I had left it for a few weeks and had not seen any real algae growth, and I assumed that the antifreeze would stop it from freezing. When I came back, the coolant tank was full of algae and the coolant in the spindle had frozen (not in the tubes or the tank, just in the spindle).

I have two questions at this point. First of all, can the spindle be saved? I assume it can't and I need to bite the bullet and buy a new one, but I feel I should ask. I don't know how to test for damage to the internal tubing in the spindle.

Secondly, how specifically should I change my coolant to be more resistant to cold? If I literally just fill the bucket with pure antifreeze (the prediluted stuff you buy at gas stations), is there any reason why it will negatively impact the functionality of the cnc? Seems like this might be an option since, the way I see it, it will pretty much guarantee that a. the coolant will not freeze and b. that algae will not grow. Thoughts?

I guess I would turn the spindle by hand to see if it's locked up or internally rubbing. If that test is OK, then fire it up and see what happens. That would quickly thaw out any ice.

I would not buy premix antifreeze, why buy 1/2 water when you can get it from the tap. Just buy the regular stuff and mix per the directions, normally 50/50 mix. That should protect you to -40.

Then go to almost any hardware store, Walmart, etc. and go to the pool/hot tub chemicals section and pick up a bottle of algaecide and add that to the antifreeze mix per the directions.

I also encountered these problems, and later added antifreeze, it worked very fast, and the bearings were changed once. My machine needs imported bearings to work better.