I need help , mig welding aluminum

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So I just got a new crapsman welder, made by clarke I think, it puts out an 85 amps at 40%. Im trying to weld (for practice) on some 1/16 in thick aluminum, with no luck what so ever. I tried all positions and settings, all I get is lots of black and wire burn back, no bead what so ever. I can weld steel, but this is my first with aluminum....help...I feel dumb.  I have aluminum wire, feeds fineI have 100% argon, set at 15-20 cfhTried all settings, nothing works good.----------OK, I got some what of a bead, still not to good though.And I am cleaning the aluminum with a brush and solvent.Please help, thanksLast edited by Underdog; 01-12-2005 at 06:10 PM.
Reply:Does the machine's manual mention aluminum in it?StangnetShop Full Of Stuff. Joey
Reply:Originally posted by vipermanz Does the machine's manual mention aluminum in it?
Reply:Aluminum is hungry for heat. Turn that mother up all the way, and try it on the thinnest scrap you can find. I am not  sure if 85 amps is enough for 16 ga. I know it sounds ridiculous, but when I mig aluminum, I have 300 amp power supplies, and it still wont do much thicker than maybe 1/2". Black soot may mean not enough sheilding gas- aluminum needs lots of gas, high flow- maybe 25 to 30 cfh.  And push it, dont pull it- that way the heat, and the gas, are flowing towards the weld, not going where you arent welding.
Reply:That is what I was going to say. Turn the gas up and push. I've been experimenting with it myself. My MM 135 will do 1/8 alu, but not more. It just doesn't have enough oomph. The best results that I got all had the argon at or about 30-35. Some black soot is normal, BTW.
Reply:Cool, I will try that. I get mixed results really, some times I get a nice bead going, other times its like Im where I started. I will try uping the gas and heat. I was pushing for the weld.Im wondering, is it normal, for example: it appears through the lens that the argon is almost a flame and the wire basicially melts to a ball then eventually drops or pushes down. But it is very slow, even with the wire speed up pretty good. Then towards the end the bead kinda flattens out...?Like I mentioned, to me this is COMPLETLEY diffrent than any steel work I have done before.Thanks for the help so far though!!
Reply:Don't forget to reverse the polarity, positive (+) ground.Consider helium for shielding gas.Also try cleaning the metal with acetone, **then heating with a propane or MAPP torch**.
Reply:He's right the cleaner the aluminum and the hotter the preheat may make your work better all the way around.CBT
Reply:i got the polarity right, I was cleaning it but i just picked up straight acetone instead of prep sol.Im making some progress though.thanks!
Reply:Based on your description of the wire feed rate, that the wire balls and drops off, sounds like the wire feed rate is set too slow.  Should have that sizzle when it is set right, and the wire is melting at the surface of the work.  But 85 amps won't weld very thick aluminum.