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Burning up TIG electrodes

7K views 3 replies 4 participants last post by  ratlover 
#1 ·
I just bought a Miller Synchrowave 180SD and I need H-E-L-P!!!

I tried out a Maxstar 150 on some scraps of 20 gauge stainless at the welding shop before I bought, just to get a feel for the process, and I found it to be easier than oxy-acetylene. I made butt, lap, and fillet joints with good, fair, and poor results. This was all done on the flat, so forming a puddle was easy. Since I was so pleased with the results on the butt weld, I figured the other types of joints would get better with practice. Now I am trying to weld 20 gauge mild steel (autobody) and I keep melting the electrode before I can get a puddle formed.

I'm trying to weld a lap joint to attach some lower door skins, with the doors on the car, so I am welding on a vertical surface this time. I have the welder set to Electrode Negative with the soft starting characteristics set at 1 (also tried it at 2) I'm running pure argon at 20 cfh. I have tried using 1/16 rod with a 1/16 tungsten as well as .035 rod with an .040 tungsten. I have tried adjusting my amperage with the foot pedal, and I have also tried holding the pedal down all the way with the machine set at 10, 15, 20, 25, 30 and 35 amps.

I've got a tight lap, with the bottom piece flanged, held together with vice grips. I even tried tacking the pieces together with my mig and then using the hammer and dolly to close the joint as tight as possible. As I increase the amperage, I go from getting the metal red hot but not puddling, to burning the edge off the top piece without getting a puddle on the bottom piece. In every case, the tunsten turns red hot and then melts back into the gas cup with a ball on the end.

After overcoming the urge to roll the damn thing out with the garbage cans, I decided to duplicate what I did with the Maxstar 150 at the shop, on 20 gauge mild steel laying flat.. Butt welds were easy, but this time I couldn't do a lap weld, so I didn't bother trying a fillet.

Ideally, I would like to take a welding course, but my work schedule makes it impossible. Any and all suggestions would be appreciated.
 
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#3 ·
I agree with bobcrman. What you describe is classical incorrect polarity. When welding mild steel or SS the electrode must be positive. (the current travels from the electrode to the work) the heat will be at the work and then melt the base metal. If the current travels from the base to the electrode, as with a negative electrode, the heat will be at the electrode thus melting it back to a ball. Note when welding Aluminum you will have a negative electrode and weld with the electrode balled. good luck. David
 
#4 ·
Change polarity. Electode positive for dc reverse polarity. Also a 2% thoriated tungsten ground to a point is a must. The Thorium increases the melting temp of the tungsten.The taper should be about 4x diameter. min. Grind point with the grind marks running parallel to the tungsten's length. about the aluminum welding, the electrode is balled by switching polarities, but then returned to electrode positive after balling the end with EN.
 
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