TIG torch overheating? (Super200P WP17)

[everlastsupport]

Brian,

Glad you are up and running and all is good. Like I said, it might be the machine. Sometime it is.

[jakeru]

Wrenchtamer, glad you're all fixed up now.

Back to my overheating torch issue. I did an autopsy of my overheated, WP-17 torch cable, (the one that came supplied with my Everlast Super200P.)

The autopsy confirmed my theory that the outer PVC shell of the cable assembly got melted inside, from the braided copper conductor not being thick enough to carry the current being used without getting too hot for the PVC jacket.

When the conductor got too hot it would melt the inside of the PVC jacket, which would offgass contaminated vapors into the argon gas. When this happened, it would contaminate both the workpiece as well as the hot tungsten itself.

Externally, the only clues were deformation of the cable in spots, and also some inconsistent feeling "hard" or "thin" spots in the PVC cable jacket. Here you can see pretty clearly a deformed "kink" in the outside of the cable:


Inside the cut apart cable jacket, (ignore the cuts in the stranded wiring - I likely inflicted those when making the cut with my utility knife) you can see the melted inside wall in many spots. In some spots, I had to pull the conductor away from the cable wall with a good bit force, as the conductor had literally welded itself to the inside of the PVC cable jacket in places. If I kept on welding through this cable with high enough welding currents for long enough time, it is likely the hot conductor would have melted completely through the wall of the PVC cable jacket.




Based on the .183" OD of this multi-braided / stranded conductor, I'm guesstimating it to be about 6-8 AWG.


The "fix" here is to use a higher current capacity cable assembly. Such a cable assembly would have either a higher melting temperature jacket material (IE: silicone rubber material rather than PVC) and/or a thicker conductor (giving lower electrical resistance, so it would not heat up as much for a given amount of welding current.) Of course a watercooled cable assembly would also likely be effective in eliminating this problem, as the conductor would typically be immersed in liquid coolant, and the inert gas would travel to the torch through its own, separate hose.

Although I understand Everlast generally no longer supplies this particular type of "WP-17" torch/aircooled cable assembly with their newer welding machines, I feel it is important for others to be aware of this potential issue.

[performance]

WP 9's and 17's typically carry this type of system. It is very common across the industry. Most 9's top out at about 120 amps, and 17's at 150 with about 30% duty cycle.