Hello all,
My first post. I hope I've finally arrived at the proper forum for this stuff. I've been everywhere and been met with mostly silence. This winter a basement workshop project has turned into a bit of an obsession.

I have recently purchased an inverter tig machine that is very compact. I learned tig on bigger machines with water cooled torches, so although this new machine is only a 200 amp ac/dc unit, I ordered it with a water cooled torch and built a water cooler for it shortly after it arrived at my door. I strongly prefer the lighter weight torch and the ability to weld with thinner leather gloves. I'd water cool even if it was only an 80 amp machine.

The parameters for this range of welding cooling is 1-2 l/min at 20 to 50 psi. 20 psi is the working pressure with 50 psi design pressure for overhead. There is no way for me to determine what the range of real heat produced/removed at the torch head during normal use.

Commercial welding coolers range from 6000 to 15000 BTU heat removal. Even that lower range is probably well beyond the requirements of a single medium sized tig torch at 200 amps. My homebrew cooler I've estimated at about 6500BTU capacity. It would be VERY useful if any of the torch manufacturers could tell me what this range is but they claim propriety!

I built my present cooler around a "dual 120 mm" CPU "BlackIce Extreme" water cooling radiator from an overclocking store online along with a pair of 120mm 100cfm muffin fans. I got a MicroPump micro annular gear pump at a lab surplus house for 30USD. I used a 1/2 gallon poly reservoir. I managed to pack everything into an 9x10x20 inch box. It works very very well for my application.

But I've challenged myself to see if I could build an even more compact version for my hobby. The first catch was locating a compact positive-displacement pump of the MicroPump type. I soon discovered that my 30USD MicroPump was purchased for 600USD new and that there is literally NOTHING available to fit the size/performance category for less than 100USD. I've looked everywhere!

It must be a gear/vane (strictly volumetric) since it must supply that 1.5 l/min reliably across a range of pressures induced by long runs of very small diameter hose (approx 1/8) and through the tiny passages in the brass head of the torch.

I could go on for many pages about this, so basically I'm wondering... with what is available today, how would any of you approach the challenge of cooling a water cooled tig torch seeing no more than 300 amps arc in the smallest package?

Microcompressors using R134a... microchannel radiators... etc? Basic, though updated, tube and fin radiators such as are used in CPU cooling? It needs to be "off-shelf" componentry that is already in use fairly broadly in some other industry or else I'd never be able to afford it.

Why is it that (consumer class) CPU cooling has not graduated to the use of miniature high pressure (positive displacement vs centrifugal) pumps and micro channel radiators? I have not found such a pump in that industry yet. Volume would have brought the cost down to what I can afford.

Thanks for any help here.