Has anyone used a standard mig welder to weld Alli ???

i know you have have to reverse the polarities but what about the gas, use a specific gas or not use any ???

how mell did it come out ??

Try this site

Linky

Pure argon gas
a nylon liner with a spring in the handle
the motor roller wheels are smooth not serrated that feed the wire
a larger hole in the welding tip ie 0.6 wire use a 0.8 tip
jacko

[Edited on 7/2/09 by jacko]

And after you have expended £30 on gas and wire, lean back and admire the mess that the pigeons have left behind.

Been there, done that and it was hopeless so took my tank to a professional and got him to weld for £15.

Subsequently purchased an AC TIG.

Proffesional MIG sets are very expensive!!!

Regards Mark

ive used mig to weld 6m ally plate. its not easy but quite satisfying when it goes well.frustrasting as hell when it goes badly .m.

i mig welded my zetec sump no problem
u mkesure the alloy is very clean and do a bit at a time.
never change polarities tho and i use argon lite gas, turn the flow up alittle.

have repaired minor surface damage on alloy wheels in the past.

Oh, and I believe that if you use a stainless(?) wire brush on the ali to be welded first, you take off the surface corrosion and get a better weld.

According to my college welding instructors anyway!

Cheers,
James

Do you need to reverse the polarity. On my welder that is only recommended for gasless welding

No you don't need to reverse the polarity but you do need to use pure argon gas and I agree with jacko on the tip size, use a bigger size than the wire is. Oh and have a few spares as I can guarantee that you'll kill at least 1 in the process of arking up (I still do this after 11 years of weldind steel and ally for a living) If what your welding is quite thin, do it in short bursts as ally gets really hot very quickly so will blow through easily. Also the material does need to be very clean, try using a wire wheel in a drill to remove surface oxidisation before you start.
hope this is of some use.
good luck.

john.

Only reverse polarities if its set-up as gasless. Otherwise keep as it is.

I've got the gas, I've got the ali wire, I've got the stainless brush. Just got to get up the courage to have a go and I'll post the result. Personally I'm just using the MIG to tack weld the pieces together so I can run some technoweld type stuff into the joints and then grind the MIG welds down to make it look right pretty. Technoweld is pretty strong but the problem is whilst you're making one joint all the others melt and the whole workpiece falls apart. MIG spot welding (even if it's sheddy pigeon poo welds) will do the trick for me.... and if it works better than planned might do the whole thing MIG....