Welding Tips and Tricks

My TIG torch just start acting up and I cannot get a descent arc no matter what I do I need help figuring this out.

Here is the best I can describe whats happening.

When I first step on the pedal the arc starts but flares like there is no argon flowing. Then the arc starts pulsing and jumping all over on the metal.

This started as my Argon got down to around 300psi, I changed tanks and it keeps doing it. I increased the Argon flow and still does it. Ive replaced all the tips and even tried a second torch and same problems... If i manage to get a stable arc, it nearly instantly burns through .095 cold rolled steel tube.

Add to this problem another issue that I think is unrelated because Ive been fighting it for a month or so. I am having a problem with my pedal that I think is a broken wire. With my pedal set to 140amps my machine will normally read 44 amps. If I move the pedal or wires it will drop to 6ams. While it reads 6 I cannot get a strong arc, I fiddle around with the wire and it goes to 44 and normally it would work.

Tomorrow I am going to call the manufacturer about getting a replacement pedal. Could the pedal also be causing the above problems???

I am using a flex head wp17 torch, Tholiated 2.4mm tungsten and number 5 cups Argon flow of 5cfh initially, and upped it to 20cfh for testing. I am just finishing off a 10 pound tube of filler, and this setup has worked flawlessly through this entire tube until the past few days. I am certain I am getting Argon flowing.

The unit is a cheap Chinese Lotos TIG200.

Any help would be greatly appreciated.

My only suggestion would be to turn on your machine, take a lighter an hold the flame in the area you do your work. If the flame moves around, then you may have a draft in the area blowing your argon away.

That was my first thought, but there is no draft or air movement. I did the same thing to make sure there was argon flowing too.

Michial,

You said it's a flex-head, and I assume it's *not* water cooled?

It's possible enough flex cycles have cracked the gas line (which is a hollow copper tube carrying current and gas) in the torch head. Your description sounds like air entering the gas stream. (In a water-cooled torch, you'll usually lose a water line before the gas line, as the coolant prevents any annealing of the copper in the "flex".) I suppose the best test is to pull the cap and consumables from the torch head, pinch the outlets in your fingers, trigger the gas with a long post-flow, and hold it under water to look for bubbles.

The abruptness of this problem suggests a break somewhere in the gas system, and your description of start-up suggests it's close to the business end.

Wait--- you said same trouble with a different torch? Look in the machine between the gas solenoid and the torch gas fitting. (Hell, check the whole gas path, but should not be between bottle and solenoid, or startup would be fine and it would go to hell after.) If you find no issues in the gas path, and can prove it's not the gas (A quality problem usually shows up at the start of a bottle, not the end), then you have a machine problem, likely a bad diode throwing AC into your weld current.

Steve S

I didn't get a chance to do any work this evening, but I was doing some thinking about this. There is one other change that I did make about a week before this started. My machine came with a 10ft line for the torch, and I had pretty much wore out the hose cover, and had worn a kink in it right at the machine. I bought a new torch and a 25ft hose, and started using it about a week or so before.

I'm pretty sure that I made no changes on the machine, especially not to the pre-flow. I'm thinking I have the pre-flow set to .1 or .2 seconds. Since the flare is at the start, and y'all are mentioning air getting into the line, I guess it could be possible that when I stop a weld and the post-flow stops, maybe enough air is being pulled back into the line that it is causing my issue...

I have a new pedal coming in tomorrow, and I should be able to get a little time to work on the buggy tomorrow night. I'll bump the pre-flow up and see what happens.