thin wall pipe

By haybine Date 09-29-2002 16:48

i am trying to weld some thin wall (.080 wall) pipe to a piece of 1/8" sheet and having a heckuva time doing so. the pipe is galvanized, but i heated it and burned off the galv and then cleaned it with a wire wheel so i know it is clean. when i try to weld the pieces together i get an awful lot of spitting and sputtering and it is very hard to start and maintain an arc. the resulting weld looks terrible and is not very strong. what could be wrong here? i suspect the pipe is a surplus piece of county road sign support pipe. could the pipe be made with some sort of alloy in the steel that will not accept a decent weld? i am using a miller 220 volt AC arc welder and 3/32" rod at 70 amps and also tried 1/8" rod at 90 amps and still not a good weld. as stated before both pieces of material are very clean so i don't suspect that, but am at a loss to figure out what is the problem. any expert opinions out there?

By pipewelder_1999 (****)

Date 09-29-2002 18:42

Try grinding the area you "burnt" that zinc from. Notice if the sparks look like regular steel. If not already doing so, use e-6011 to weld with. This should vaporize any small amounts of zinc.

As far as being an alloy steel it is unlikely that that is the cause. If the pipe is oly .080" think, its possible you are melting through the pipe and picking up zinc from the internal surface.

Good day

Gerald Austin

By welder_guy2001 (***)

Date 09-30-2002 19:37

yeah, sounds like there's still some zinc on it. when you heat up the pipe to burn the zinc you'll actually see the zinc burning w/ a white flame, and you can hear it crackling. when you take the heat away you'll see where the zinc has peeled back from the steel farther up the pipe from where u were heating. usually the zinc burns off when the steel turns red hot.

and yeah, like gerald said...the 6011 rods work well for dirty metal. the harsh arc burns off all kinds of nasties.