Aluminum Mig Welding with Spoolgun Multimatic problems, please help!!!

[cwilliams2000]

Let me start by saying I am obviously not a pro. I bought the multimatic last year and did some steel and it went pretty well but I definitely need more time with it.

But: I wanted to do aluminum and I am definitely doing something wrong in a major way. I have the spoolgun 100, 100% argon, I was trying to welding a 3/8" solid aluminum rod to a tube frame which is 1/16". Previously I had the same problem I will describe so when the results came out the same, I know I am missing something.

I used the regulator that came with the MM kit and have et it to between 10-20CF per hour.

Power was on 25volts and wire speed around 350.

The minute I lite up, it looks like gun is shooting a green flame, I never really can even properly see the arc or much of anything and it sounds like its breathing fire. I am doing electrode +.

The welds don't penetrate well at all, they are nearly instantly filthy and black soot all around.

I am not sure what I did wrong, when I learned on steel I could see some improvement, but I have tried this maybe 6 times now and I can't even get one single clean weld, they do penetrate some but they are about the worst I have ever seen.

I would appreciate any help you can give that could let me see what I have missed.

Christine

[MMW]

Turn your gas up to 25-30cfh. Angle the gun so you are pushing at about 15* instead of pulling. Try on some flat pcs. first. You will almost always get soot but when everything is set right you won't get much.

What size wire are you using?

[aametalmaster]

What size wire? I would say you have the dreaded cold start being that the rod is 3/8 and the other tube is thinner. Not sure on the voltage as my welder doesn't have a meter but i would say you need some practice on some tube the same thickness on both parts...Bob

[Goodhand]

Your aluminum might be anodized. You may not be getting adequate gas. Your argon may be contaminated.

[taylor21]

If aluminium surfaces are anodized it become harder than aluminium but it have low resistance that can be improved with the increasing of thickness and also by applying suitable sealing substances.

[cwilliams2000]

If aluminium surfaces are anodized it become harder than aluminium but it have low resistance that can be improved with the increasing of thickness and also by applying suitable sealing substances.

It's definitely not anodized and I cleaned it up quite a bit with a new scotchbrite pad. The wire is .030 I believe, and from the notes here I am thinking the gas flow might be too low, I will try to crank it up some, it was very odd since I knew about pushing and not pulling and even when the weld first starts, its like its an instant mess, so the gas could be the ticket I hope. I will try again and let folks know.

Any other ideas definitely let me know. Thank you!
Christine

[Goodhand]

If aluminium surfaces are anodized it become harder than aluminium but it have low resistance that can be improved with the increasing of thickness and also by applying suitable sealing substances.

It appears you are referring to the electrical conductivity (as in transmission of power) of aluminum when you state that aluminum has low resistance, improved by increasing thickness (of wire). But, that really is not the issue, here. Anodizing will resist initiating current flow. According to Alcoa, 800 V is required to pass current through 1 mil of anodized coating.

[jpence38]

Your volts are too high and/or your wire speed is too low.

For an .030 wire (and I will guess it is a 4043) you should be starting out at about 22 volts and 450 wire speed on the low side, then make adjustments from there.