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MIG/TIG outside corner joints?

Posted: Tue Mar 29, 2016 5:42 pm
by AKmud
I've been building several aluminum tanks lately and have been fighting my gas coverage when doing outside corner joints. Have you guys come up with any tricks to keep the coverage consistent? Most of what I'm doing is 1/8" 6061-T6 both MIG and TIG.

Re: MIG/TIG outside corner joints?

Posted: Tue Mar 29, 2016 9:17 pm
by exnailpounder
I have run into that a few times. Piece of angle fastened, however you can, on both sides of the weld to create sort of a fence on both sides of the weld. Keeps gas from splitting on the corner and drawing in air. Kind of hard to explain but I bet you get it.

Re: MIG/TIG outside corner joints?

Posted: Wed Mar 30, 2016 7:17 pm
by Braehill
Mud,
Go an inch down each side and put aluminum tape, only sticking the top half and bend it back over itself, then lift it up about 45*.. This traps the gas as it tries to flow down the sides. Acetone will take the glue off if it gets too sticky (it will most times). You can also tape across the inside of the corner if it's accessible, just don't push the tape into the corner.

The angle trick works if you're able to clamp it. If it's something that you're doing a few of, then you can tack up some angles that can be draped over your corner leaving a gap to weld in between. I have one at work that's about 4' long and has flat straps welded on each end to hold them at a 45* angle leaving about 3/4" gap.

I also use a standard cup instead of a gas lens when I have outside corners to do.

That just a couple of things that I've found that work

Re: MIG/TIG outside corner joints?

Posted: Wed Mar 30, 2016 9:04 pm
by Bill Beauregard
Aluminum outside corner joints everybody but me finds effortless. In past I've had issues with shielding. I believe where gas can blow into the gap, it can create turbulence contaminating the gas with air. I have some copper blocks, Two of these are 1-1/2" square one six inches long, the other maybe 18" one corner of these is radiused to allow a bit of gas coverage, and leave a little void for filet to form.

Re: MIG/TIG outside corner joints?

Posted: Thu Mar 31, 2016 2:08 am
by AKmud
Thanks for the tips guys, I'll give them a try.