I have tried several low cost methods to keep my cooling water on my 50 watt laser at an acceptable level, but finally seemed to have found something that works. I have seen variations of this but not this exact method.
I took an old cooler/ice chest that was laying around and drilled two holes in one end at the top just large enough to get the cooling tubing through each hole.
A coil of tubing (I think its about 50 ft) was placed in the cooler and the ends brought out of the two holes.
The return water from the laser tube was then connected to one end and the other end is sent back to tank after running through the coil in the cooler. The cooler is filled with water an inch or so below the holes.
Before I start to use the laser I place several freeze pacs in the water to chill it down.
I’ve used this the past few days running some cuts at about 65% (which is not too far away from the max power point for this machine. The laser cut about 15 to 20 minutes at a time for several cycles and the water never got above 20c. A huge improvement over what it was doing before.
If more cooling is required it could be accomplished by adding more tubing inside the cooler, or better yet, change the tubing in the cooler to a larger size to slow the velocity of the water allowing it more time in the chilled water.