Forgive me if this has been asked before, but can a closed loop water pump be used for the cooling (i.e., like ones used for cpu/gpu’s)?
I am not sure, but from my experience with my watercooled spindle on a cnc, it barely handles that. I really do not see being able to use just a cpu cooler by itself, maybe with a small reservoir it might work. If you do try it, make sure you have a temp guage and shut it down if the temp gets too high. Don’t want to fry the tube.
Yeah, I was just thinking of using the pump, large reservoir and radiator
CO2 tube work best close to 15°C water, some use frozen water bottle in the bucket to reduce temp. (depending on seasons and where you are on the globe)
I use an Aquarium heater - cooler - digital controls - cooler feeds tube first, then water exits into a 4 litre container which then feeds the pump, the pump feeds the cooler - works very well in my basement location. These coolers are fairly cheap and made for 24/7 operation
@greg_greene what cooler are you using?
@greg_greene interesting there was a discussion on these some time ago and users reported that they did not cool enough. I think these are peltier coolers/heaters?
Yes, mine works well and there are more on their website that are perhaps more suited - but it works well enough for now. I track the digital thermometer as I use the cutter and it seems to keep up fairly well. One thing I do do, is to start it up a half hour or so before I start cutting so that the reservoir is well chilled, That helps a lot.
@greg_greene I may try this summer.
Most of the PC watercooling pumps are not submersible, you need to have the pump below and outside the tank, then it´s ok to use PC watercooling pumps. You still need the volume of coolant though, like 2-5gallons atleast.
Plenty more flow in them than the china fish tank pump.
I built my complete cooling loop from PC cooling parts. tubing, radiators, fans, fittings and temp controllers with a 240mm radiator outside my window with four 120mm fans, works really good in the Swedish climate 
So it’s not a closed loop system then? I didn’t plan on submerging it. I was thinking either externally mounted 240 or 480mm radiator and a couple of in-line reservoirs , which I would think could dump the heated water/coolent pretty efficiently. What are you keeping the 2-5 gallons of coolent in? Have a picture of the setup by chance? Thanks
I have a closed loop water cooling setup with a 120mm radiator and it works well enough for short runs. I would recommend going larger though - 240mm at least. I’ll probably switch mine out with 240mm if I start running the laser longer than 1-hour straight. (see mid-way through page for my build for reference http://jimmybdesign.com/k40-laser-cutter/ )