Question for the group.

Question for the group. It’s winter and time to change the coolant for my K40. I’m already using deionized water. I’ve read of people adding some chlorox to keep stuff from “growing” in the water, anti-freeze to prevent freezing, etc.

My question is, what is everyone doing to their coolant water to keep it clean and prevent it from sapping energy from the laser?

I’ve had my k40 a little over 5 weeks. The laser is in my unheated workshop where outside temperatures can drop below freezing. I’d appreciate any suggestions.

beware with antifreeze as it can increase the amount of current bleed into your reservoir. See more info at for detailed numbers.

Do not use antifreeze during operation. You have to either heat and circulate the water or drain it if you are not using it.
Some use aquarium heaters to heat and control the coolants temp in winter, you can search the community for that info and others will chime in.

what about the Clorox suggestions I’ve read. I want to keep the system clean but don’t want current loss either.

What is the current path from the gas discharge inside the tube to the cooling water? Is it through the glass wall?

Yes, the laser is running at high enough voltage to overcome the dielectric strength of the glass. Fun stuff starts happening at thousands of volts.

@TwelveFoot We dont exactly know the mechanism I think the tube and water act like a big capacitor at this voltage.