Bulb shape build up on tungsten?

[chipz]

Could someone please explain why I have got build up on the tungsten. I am welding 1/8 Mild steel with 70 amps, 9 cfh, 2.4 tunsten with sharp point and 1/8 protrusion from tip. I am welding in a push direction. The weld is smooth in appearance although there aresome small ***** scattered around on the weld which I dont understand. The buid up occurs after about 3 inch of welding.

I have doing ali and this is the first ms I have done.

I have switched from ac to dcneg.

[Ed in Ga]

Chipz,
You might try increasing the Argon flow to 15cfh and have a small flat on the tungsten end. Don't use pure tungstens on steel, but I'm sure you are not.
Hope this is of some help.
Ed

[chipz]

Thanks, It could be pure the paint has come off a couple and I could have mixed them up.

I will try the same weld with a red one.

[Mike Sherman]

Chip, you are getting contamination on your tungsten. Those little ***** and the build up on your tungsten are the same thing. Try cleaning your material better, use DC -, a sharpened 2% thoriated tungsten, and try moving the torch a little farther away from the weld. There are alot of things you could be doing wrong and teaching someone to weld on the internet is difficult, I usually don't do it. Good luck and let us know how you do.

[chipz]

Mike, you are bang on regarding material condition. I was welding some of that orange warehouse racking and it was still orange.
LOL , I am used to gas welding and the autoprep of the flame ( other words a lazy sod) so I just got on with it.

I will now prep the material properly.

Thanks, for your time.

[echo8287]

Mike Sherman

That Mike Sherman is a heck of a nice guy!

[chipz]

The tungsten was wrong one as well. I put a red stripe in and it welded about 1 yard before any problems.

Thx for your help