[TheForge] tig welding problems

[Loktr at aol.com]

I am tig welding schedule 80 black  pipe.  The argon is set on 30 to 50 on a 
Co2 flow valve. Straight polarity, high freq start.  I am using a gas 
concentrator nozzle with .125 electrode and 3/32 steel for tig filler rod.  Every now 
and then I will get a gas bubble in the metal, when I try to reheat the area 
to float the bubble out it seems like it moves around and I can never get it 
out.  What am I doing wrong?  By the way the steel is wire brushed as well as 
the forged steel fittings.

Ben