GMAW STRUCTURAL ALUMINUM

[OMS]

Hello.

Just registered with the forum. Thought I'd ask the MIG Aluminum welders how they start GMAW without the problem of a cold start concerning .250" thick and thicker material. The start of the weld does not tie in until HAZ catches up with torch movement, about ½ inch or so of travel. I have tried hot-start option but do not know if I am utilizing it properly.

I could possibly be spoiled as I GTAW Aluminum 90% of the time and you know how easy it is to control heat input using a foot pedal.

Have found that Pulse mode seems to work ok especially concerning out of position welding.

Anyhow, my machine is a Lincoln 350MP with a dedicated Python push-pull gun, 3/64”- 5356 filler and 100% Argon.

Looking forward to hearing from you soon.

[junes]

ok i can think of three posibilties. so here goes...
1) start the arc on the very edge of the joint almost on the side and start there by the time you get to the actual joint you should be good to go.
2)pre heat a little especially at the begining.
3)start about a inch or two into the joint then go back to the beginning of the joint.
once you get to the start you can trace back over and the already laid bead and
just keep going and then the the weld should be good.

[JJW]

Hello OMS,
I've done the back track at the start of a MIG weld on 1/4" aluminum to pre heat it.
Also have used Oxy/Acty to pre heat
Regards,
John

[junes]

The back track method I found works really well in the past.