Does a MIG machine for alu have DC/AC switch?

[chy_farm]

I have a good pro grade TIG welder but it does not allow me to use one of my hands, lol, so beginning to think of buying a MIG machine for aluminum. Most of the ads I watched so far on MIG machines on the net seem they do not show if they run DC, either with AC current. Some semi-pros say they can do aluminum MIG with their machine but still I do not know if they can use AC mode for alu. I know welding alu requires removing aluminum oxide from the surface of the spot we aim to weld, by loading negative polarity for parent material, and positive for tungsten, whereas in MIG the wire needs to be negative when it melts.

So my question is;
Are there MIG machines that have DC/AC switching?
Thanks in ahead.

[FusionKing]

NO
A multi-purpose machine may have AC for CC welding but Mig is DC for CV welding.
I have know idea if it is actually possible to do or not, but I'm sure it would be really noisy if you could get the arc to carry.

[chy_farm]

Thanks FusionKing , your tip sound right, watched Utube and this guy says he uses "electrode positive" for MIG;

but I do not know the reason why???

[OscarJr]

Aluminum MIG is DCEP, since EP both removes the oxide layer and melts the consumable electrode, otherwise known as the filler wire.

[snoeproe]

All mig is dc. Ferrous metals or aluminium.

[ryanjones2150]

Friend of a friend bought a cheap-o mig welder...from northern tool I think...anyway, guy couldn't lay a useful bead with flux core to save his life. I told him I swap the polarity and his world will be happy again. He ever so cleverly informed me that I was wrong and that the problem was that his mig welder was an AC only mig welder and he was using DC mig wire. True story.

[FusionKing]

Friend of a friend bought a cheap-o mig welder...from northern tool I think...anyway, guy couldn't lay a useful bead with flux core to save his life. I told him I swap the polarity and his world will be happy again. He ever so cleverly informed me that I was wrong and that the problem was that his mig welder was an AC only mig welder and he was using DC mig wire. True story.

Man do we ever need more smilies on here

[OscarJr]

Friend of a friend bought a cheap-o mig welder...from northern tool I think...anyway, guy couldn't lay a useful bead with flux core to save his life. I told him I swap the polarity and his world will be happy again. He ever so cleverly informed me that I was wrong and that the problem was that his mig welder was an AC only mig welder and he was using DC mig wire. True story.

so what happened after he told you that?

[FusionKing]

so what happened after he told you that?

I would have just let it drop at that point, I mean heck, you sure can't fix stupid. I've tried a lot, and realized that was just as stupid.

[ryanjones2150]

At first I thought he was screwin with me, but then he continued to explain how he had called the manufacturer of the machine and that is what they told him. I simply said, "oh. Well sounds like you have it all figured out then." He was so proud of himself for solving a great mystery of the world, I just let it be. Every time I see the guy he wants to talk welding, so I just let him ramble, agree with his assessment and nod my head.

[FusionKing]

I have guys from other shops pick my brain on junk like that.
I used to fight it. Then I decided if they all got smarter we could all charge more. But.....some are beyond help, for various different reasons

[ryanjones2150]

I probably could've screwed with him..."make sure you have a DC only ground clamp...", but I don't like the guy. I don't mess with people I don't like.

[Ltbadd]

Wait, there are different ground clamps for AC and DC! I wonder which clamp came with my machine....

[Almond farmer]

The 90 amp flux core wire feed welding machine from Chicago Electric/ Harbor Freight is AC , only, no MIG capability
Would probably weld CS sheet metal ,only, with lots of splatter, no aluminum capability.

what's z difference between AC & DC ground clamps?

[aametalmaster]

.

what's z difference between AC & DC ground clamps?

The price. AC is $8.99 and DC is $10.99. Well that's what I sold them for...Bob