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Mig Welding Aluminum Pipe.

Posted: Sat Mar 21, 2015 8:03 pm
by Daantman
Picked up a side job with a engineer friend of mine producing aluminum box truss. Of course the customer wants it as soon as possible and I told them you cant rush this stuff. Im 90 percent complete with job and been mig welding the truss which is comprised of 1.5" schedule 40 and 1" internals using a power mig 350mp. Ive encountered some poor weld quality about 3/4 the way through welding each truss section. My aluminum is clean and free of debris and didn't know if I'm overheating or should of tig welded it to start with. Any pointers would be greatly appreciated.

Re: Mig Welding Aluminum Pipe.

Posted: Sat Mar 21, 2015 9:44 pm
by weldin mike 27
Welcome to the forum. What's your background?

Re: Mig Welding Aluminum Pipe.

Posted: Sat Mar 21, 2015 9:49 pm
by Daantman
Fencing industry welding aluminum handrails for 10 years.

Re: Mig Welding Aluminum Pipe.

Posted: Sat Mar 21, 2015 10:45 pm
by Superiorwelding
Daantman,
Welcome to the forum. I am experienced with the 350MP running both steel and alum and might be able to help. We first mess a little more info. What exactly do you mean by "poor weld quality?" That leaves te door wide open. Also, are you running pulse, pulse on pulse and what are your settings/wire? A picture would help as well.
-Jonathan

Re: Mig Welding Aluminum Pipe.

Posted: Sun Mar 22, 2015 7:47 pm
by Otto Nobedder
"Three-quarters of the way through," every time, may suggest you are hitting a duty-cycle issue, with either the torch, or the machine.

The other alternative I see, is you've built so much heat into the metal ahead of you, that you need to back off the power input about 1/2 - 5/8 the way through that weld.

These are guesses, since the information was a bit limited.

Welcome to our neighborhood!

Steve S