I have owned my K40 for several years and I always used distilled water as a coolant. It is permanently installed in my portable shop. I lived in northern California where it freezes and snows in the winter and never had an issue with the K40. Last summer I moved to Reno NV which is a higher elevation and has a longer period of snow and freezing weather. I used it after I moved but I never used my shop or my K40 over the winter and this spring when it was warmer I found that laser tube had shattered. I had heard that antifreeze was a no no for CO2 lasers and I have no way to heat the portable shop during the winter. I assume it shattered because the distilled water in the tube froze?
What is the best solution? I heard that there are non-conductive antifreeze coolants for CO2 lasers. Has anyone used these in a K40 with success? Or am I barking up the wrong tree?
Adding many things will raise the dielectric constant. I’ve used a number of things, such as propylene glycol for cows, that lowers the freezing point without messing with it’s conductivity.
I moved a bit up north (center of Arizona) and I run a coolant by OMTech. Good down to -31F. You can get it through Amazon also.
It is basically antifreeze, but it has none of the additives that you get with automotive antifreeze that causes the coolant to be conductive.
You can read up on some of these here… take it for what it’s worth to you.
