Tig bad low amp starts

admin

I have this weird issue that recently developed with my dc tig welder in lift arc. The problem is somtimes on low amperage starts it sounds like it’s arcing inside the cup to something? It doesn’t do it all the time and when it does it’s impossible to see anything and I don’t see any burn marks or other evidence of what is happening after. Changed the cup and insulator many times and it still happens. Put a glass cup on hoping to see the issue but I still can’t see the problem. Any thoughts? Nothing inside the torch body has any evidence of arcing that I can see simply by removing the consumables. It happens when starting below about 80 amps, it’s more of an annoyance then anything, but I cringe every time I hear that happen.
Reply:Which machine do you have and is it producing an arc at all or is it just making noise? Which type of tungsten are you using and what diameter?Is it possible the torch head is broken under the rubber sleeve?We had some very cheap chineseium torches a vendor gave us once that all eventually broke in the neck of the torch body. The copper that carries current to the torch consumables/tungsten through the torch neck would get brittle and break. Looked like a dead chicken because the cup would flop around on the torch body since it was still attached by the rubber sleeve but they still worked somehow. One of them got used until the broken copper cut through the rubber and was poking out the side. That one did stop working at that point.
Reply:Thermal arc fabricator 211I, 3/32 2 percent thoriated, CK 20 series water cooled torch flex head.  (I didn’t think of trying 1/16) It lights off fine the torch neck isn’t broken it just occasionally makes a really aggravating almost short circuit mig sound but higher frequency on low amp starts but still lights off. The noise disappears as soon as the arc is going. Only happens occasionally I put an air cooled torch on (the thermal arc brand one that came with the machine and was able to recreate the issue)
Reply:How is your hearing? Could the sound actually be coming from the power source and only sound like it's from the torch?With the power off, what is the resistance measured between the collet holder and the power supply terminal [the (-) one?] where the torch cable connects?What metal is being welded and what polarity is being used? Does that seem to matter at all? I don't know that machine so won't try to ask about settings like HF and such, or testing with different ones.
Reply:The 211i has a sticky lift start for sure but I'm wondering if your collet and cap are cinching down tight enough. Are you using CK consumables?Thermal Arc 320SP ( Lorch )Cobra PythonsThermal Arc 300 AC/DC  ( Sanrex )ESAB 301i AC/DC  ( Lorch )Thermal Arc 161STL  ( WTL )Thermal Arc 190S  ( Sanrex )Cut Master 82, 42. Cut45 ( WTL )Victor Gas Apps.Boxes and boxes of welding crap.
Reply:Well oldiron my hearing sucks as I have worked in industrial settings my entire life and never used ear plugs until recently. I checked the resistance and it was .02 ohms less then the resistance of the meter leads. This got me playing around with it I stepped on the pedal with the torch away from the work/ground clamp and to my surprise it arced internally. I decided to check the open circuit voltage and I had 80 ish volts. As I mentioned this is an intermittent issue I stepped on the pedal a few more times and to my suprise one time I had almost 400 volts DC open circuit! I think I’ve found the reason now guess I’m going to have to take it apart again and try to figure out the issue. It’s obviously arcing to the cooling water and grounding through the cooler. Hopefully it’s something obvious otherwise I’m going to have to wait until the problem becomes more frequent to figure it out.