New issue with high amp arc starts on 160STH

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01-29-2013, 01:43 AM
youngnstudly

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New issue with high amp arc starts on 160STH

So I just went out and continued welding the corners on my 20 ga. sheet metal doors, and after a few short welds, I noticed I no longer had the ability to start a low amp arc. When I hit the pedal lightly, the arc is either "on" or "off" (like a light switch) and even the slightest release of the pedal will cause the arc to go out abruptly. Also, the second I light up with the pedal, my nice needle point tungsten gets a blunt point, but does NOT turn charcoal color or become contaminated.

I'm running 7 LPM (or whatever the unit of measure is on the Everlast flow meter) currently, 3/32" thoriated tungsten, number 6 cup, and the ground clamp is directly attached to the base metal. If I stab the pedal and put the torch to my ear, it blows a steady stream of shielding gas at me. I just checked the basics (my connections all seem tight and the torch parts are snug).

Pics are attached of previous (controllable) welds.
The first pic is my typical slightly hot weld using .035" MIG wire as filler, and the second pic is a slightly cold (not to mention, rough) weld from using the bigger 1/16" carbon steel filler rod. Obviously I was able to at least control the puddle and width of the bead on each of those passes (even if they aren't very pretty).

The last pic shows the result of me using the lay wire technique with 1/16" filler and jamming rod in frantically while trying to fill a large keyhole (no control at all during the entire weld). I never had to do that on the previous welds. If I had to guess, I'd say the lowest starting amps are around 30 or 40 amps. I should have looked at the digital display to see what the actual start amps are but it didn't cross my mind until just now (it's really a moot point anyways). The machine was working flawlessly before I ran the last few beads.

Any ideas or suggestions? All 3 pics were welded today (just FYI). I would have called Everlast support, but it's after 6:00. Thanks for the help.
01-29-2013, 02:24 AM
youngnstudly

I just checked resistance between the pins on the pedal, and between pin numbers 1 and 2 I get an "OL" reading on my meter when the pedal is resting, and between .3 and .4 ohms resistance when depressed. I found a label on the pedal that says FT-22k-CL (for what it's worth).
01-29-2013, 02:42 AM
Rambozo

I would open up your pedal and have a look at the mechanical portion. What you describe could be that the belt has slipped on the pot, so you have the switch part but not the current control. A few people have pedal issues and if you search the forum you can find a few different ways of improving the belt system. Usually you just need to adjust things a little better and all the parts are still good. I'm not sure if it's poor QC on the pedal, poor design, things coming loose in shipping, or a combination of all of them. It's probably an easy fix. You can check resistance between pins 3, 4, and 5 for the pot.
01-29-2013, 04:45 AM
youngnstudly

Quote:

Originally Posted by Rambozo

I would open up your pedal and have a look at the mechanical portion. What you describe could be that the belt has slipped on the pot, so you have the switch part but not the current control. A few people have pedal issues and if you search the forum you can find a few different ways of improving the belt system. Usually you just need to adjust things a little better and all the parts are still good. I'm not sure if it's poor QC on the pedal, poor design, things coming loose in shipping, or a combination of all of them. It's probably an easy fix. You can check resistance between pins 3, 4, and 5 for the pot.

Cool, that sounds reasonable enough. I'll check it out in the morning.