Replacing a leaky and worn out WP-20 water cooled TIG torch -

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Offline goodfellow

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Time to upgrade this old 15ft. torch. I installed it in the early 2000's and it's starting to leak and the hoses are getting brittle at the connections. In fact the power hose has a crack in it and a small leak -- that's not good. I have ordered a new 25ft complete WP-20 flexible TIG torch rig, but I'll rebuild this one as a spare.

This is something that anyone can do with basic tools --

Water cooled Torches have three connections - 1) water-in, 2) gas, and 3) a combination power/water return hose. In most cases they are easily identified.

Here is an old Weldcraft WP-20 torch -- I've patched it for some years now, but my original wire clamps held. Now the water-in hose and the power/water return hose are brittle and leaking behind the clamps.



The power/water return hose is easy to ID -- it's the one with the large brass connection (both on the torch body and the hose end). The water-in and power/water return hoses are usually a larger diameter than the gas hose.



The three torch hoses terminate in three places on the welding rig. In addition, the two water lines connect with reverse threaded fittings, while the gas line connects with right hand threads.

Water cooler connection is reverse threaded 11/16" (notice the characteristic check mark on the fitting indicting reverse thread)



The power/water-return line connects to the welder lug and is a 13/16" reverse fitting.



The gas line connects to the gas solenoid and is a 11/16" standard right hand thread



On the torch, the power/water return are the larger fittings that are standardized 1/4" size (for US manufacturers, but on the newer imports they are 7mm -- the fitting threads themselves are the same between OEM US and Asian WP-20 import clones).



Here's the culprit -- broken and cracked. It can't be cut because underneath is a braided power line surrounding a water return inner hose. Hence I used high strength heat shrink tubing to patch the section and then made wire clamps to seal it. The wire clamps are simply stainless steel wire wrapped twice around the tube and twist tightened with a pair of slip joint pliers.





The gas and water inlet supply line are simply plastic tubing that I trimmed to get rid of the cracked pieces and refitted to the torch.





Since we already know the power/water return hose is the one with the brass fitting, the two remaining tubes must be gas and water inlet. You ID the gas fitting on the torch by blowing into the tubes and checking for air at the torch head.

This is the new torch -- notice that beside the larger brass power/water return fitting, the other two fittings also have brass ferrules. Those ferrules are used on more  modern torch supply lines that have appropriate fitting. My lines don't and are just plastic. The ferrules can be unscrewed and set aside -- I don't need them.







First step to a new torch is to slip the handle on the lines (this is often overlooked and there is no way to attach the handle afterwards)



Next, the remaining hoses are attached to the appropriate torch tubes -- I used a heat gun to slight heat the plastic tubes and it makes them slip on the fittings much easier. Then the fittings are wrapped twice around with SS wire and tightened with the pliers. It takes a feel -- too tight and the wire breaks; too loose and it leaks. It's not hard, but a few tries may be needed.





I checked all the fittings for leaks and the gas with soap bubbles -- all good. Slide the handle back on and it's good to go as a workable spare.



The new torch body cost $11 on ebay and it's a big improvement over the original WP unit that I had -- much more ergonomic. 


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Online rusty

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Re: Replacing a leaky and worn out WP-20 water cooled TIG torch -
« Reply #1 on: March 13, 2018, 02:31:23 PM »
Very interesting. So 10 to 18 years of use before they got brittle?
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Offline goodfellow

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Re: Replacing a leaky and worn out WP-20 water cooled TIG torch -
« Reply #2 on: March 13, 2018, 10:14:04 PM »
Very interesting. So 10 to 18 years of use before they got brittle?

Yes, the torch was used quite frequently lately (after sitting idle for a almost a year) and it just started to leak at two of the joints. In my case that's about 16 years of use -- not bad.