We needed water cooling for the new resistance welder we got and the $500 price tag on a pre-built model was a tough pill to swallow. We put this together for less than $200, so it’s worth the effort to have a cooler with a live readout of temperature and flow, for less than half of a stock unit’s cost. Obviously, the aluminum reservoir isn’t necessary (the material has been sitting around for 6 months), but you probably want to get something that holds at least 2 gallons.


-The fans are wired with the neg(-) to the black with white stripe, pos(+) to the wire next to it, to push it through the cooler the way they are mounted. The 3rd wire is just capped.

-All you have to do is match the wires from the flowmeter to the tachometer display and throw away the tachometer pick up (magnet and threaded metal piece with the wires). “450” displayed on the tachometer equals one liter per minute, so 2250 on the display equals 5l per minute (about 1.25 gpm), which seems to be plenty, with the 2 gallon reservoir, to keep the tips, transformer, and coolant at room temperature.

-Flowmeter threads are 1/2 NPT, but don’t seal on the threads, so add a #11 o-ring on both sides inside the threaded side of your barb fittings.

-Video at the bottom shows the noise it makes and read outs.

Parts list:






-Power Supply

-Flowmeter Readout


-110v Power Cord






We assume no responsibility for injuries, death, equipment or property damage, or bruised egos if you attempt to build this. Not liable, lawyer talk, all that stuff.