im welding up some 1/4" mild with my millermatic 135, and on one or two of the welds the porosity is ridiculous. i tried to tig over it and the bead would just get even more porous, i shoved tons of filler in it and nothing, its like the rod was disappearing.

im stumped, anyone have an ideas?

only thing i could think would be some bad contamination, and it just cant ever go away.

 

bad tank of gas is my guess.

 

Is it that the gun has slipped out at the feed rolls and gas supply holes don't line up?
Is your nozzle clogged?
All gas connections are tight and free of damage?
How well did you clean the material?

All just guesses to get your brain rolling...

 

maybe a draft from the heater or ceiling fan? maybe even the cooling fan of the machine itself

 

cant be bad gas because its only on one or two welds, then after tigging it it still is messed up.

tig and mig uses 2 separate tanks.

im stumped, lol.

i cleaned it fairly well, but its mild and you dont have to clean that super well.
i mean i cleaned it just as much as i cleaned the rest of the metal that welded perfectly fine.

very odd.

 

once you have porosity tiging over it will not get rid of it nothing will but grinding it out

 

yeah i was just curious what was causing it.

 

maybe contaminants from the "behind" side.

 

very strange because its just mild steel, nothing else on it. and the backside wasnt getting the full penetration with the mig.

 

Werd.

I get this sometimes tigging. The metal will be clean and everything. It will just start popping and porous and will not come out. No matter how much I swirl it.


I figured it was from a break in shielding gas from a breeze or something.

 

contamination is my final answer it could be insid and seeing its mild some companys dont keep up on quality and are to busy with mass production they slip up a bit that or either it was grease resadue that happend to be clear either way best thing to do is grind it out and start it again that happends alot when welding aluminized

 

Mildsteel isnt as clean as one might think, theres **** embedded in the metal.

 

thanks for the confirmation guys. ill grind and reweld.