Tig welding keeps bubbling

by Eric
(Fallon, NV)

Hello Jody,
I am in the NAVY and we are incorporating a new hitch onto our tow tractors. Things have been running smooth until today. We have done about 10 hitches total with no real big problems. Well today is something different. Everything went good until it came time to do the bottom seem. Started out with a good bead, but about halfway threw, it bubbled and started popping. No big deal, grind it out, clean it up and run a pass over it again. Well that didn't work this time. We have done almost 10 passes on this 2 inch seam with no luck. We have checked the flow of gas, changed all the components on the tig gun. We have even enclosed the area where we weld, thinking that the outside air was disruppting the gas coverage. Well now we are sitting here sctraching our heads! Jumped online and came across your site, and figured it wouldn't hurt to ask.
Thanks,
AM2 Timme, USN

------------------------------------------------
Eric,

sounds like you are sealing up something and pressure has built up from the heat and wont let you seal it.

can you drill a small weep hole to let internal gas pressure escape? you can weld the hole after all has cooled down if need be.