source for 3003 0.063 inch in MN

[sandmanred]

The heat of tig welding should anneal the weld line for 1100, 3003 and 5052 alloys. Annealing again after initial planishing should help as well. I've found that 1100 filler doesn't harden up so much as 5356 so I use it where I can

[steve.murphy]

Thanks Jeff. I saw a YouTube video recently where the guy said he runs the tig along the backside of his weld joints which helps with the cracking. I think it was cornfield customs.

[sandmanred]

I agree. There's usually some deep grooves on the backside that could initiate cracking. I try to wash over the back and add filler if needed whenever I can reach the backside of the weld.

[billfunk29]

Back purge with argon if you can. Nice smooth back bead. Or gas weld, if you can tolerate the flux.

[crystallographic]

It's been generally accepted by (US) aluminum auto/racing/aviation fabricators that tig welding aluminum needs back purge to achieve 100% penetration.
(I have spoken to the tank builders for the KW, Pete, Bulldog, etc over-road freight trucks ..... who were tigging ... cleanroom environs .... backpurge .... cameras inside tanks .... getting leaks constantly ..... another story...)

All that aside, the aluminum tank fabricators (drag/salt/Indy) gas weld the tanks with O/H or O/A, and not usually leak-testing them.

So...a story from a few years back:
I was trading yarns about metalworking with a drag-car owner/builder/driver and he told me a story from his previous season, and a gas-welded aluminum tank -
It was mounted in a tube-cage at the rear of the car, pressurized by the blower.... no fuel pump on the car.
During one race the blower sneezed and so they pushed the car back to the pits, pulled the bodywork off the rear, exposing the tank for pulling and inspecting......
The tank had puffed up a Lot, swelling so much that it quilted through the bars of the cage, making it impossible to extract without cutting the 4130 steel tubing.
So they leak-tested the tank in place - at 14psi - no leaks - and ran it "as is" for the rest of the season.

("if you can tolerate the flux")

- end -

[DavidB]

if you can tolerate the flux

Not sure if that's supposed to indicate the flux remaining may be an issue but my experience with aluminium welding with OA here in the UK is that the flux is so deliquescent that after welding I would go away for half an hour or so and when I came back the flux had absorbed so much water from the atmosphere it had dissolved and run off the part so just rinsed and done.

[crystallographic]

Originally Posted by DavidB

Not sure if that's supposed to indicate the flux remaining may be an issue but my experience with aluminium welding with OA here in the UK is that the flux is so deliquescent that after welding I would go away for half an hour or so and when I came back the flux had absorbed so much water from the atmosphere it had dissolved and run off the part so just rinsed and done.

... or hygroscopic ...