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Welding thin aluminum


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I'm currently working on some aluminum piping for my intercooler, and I need to make and weld on a flange for my BOV. At work, I have access to a Miller XMT-304cc/cv.

 

I was wondering if I could weld the aluminum with this welder. We do have all of the MIG and TIG attachments, but I've read that you need to use AC when welding aluminum and this is a DC machine.

 

One of the guys in the shop is going to teach me to weld with TIG, and I intend to get a lot of practice before I actually weld on my pipes. I've always wanted to learn TIG anyway. This is just a good excuse :) .

 

Is it possible to weld aluminum with standard ferrous wire(MIG)? I'm not concerned about looks in this instance, i just need it to hold together. Also, can you weld/braze brass fittings onto aluminum?

 

Thanks!

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for some mig weders there is an attachmnet called a spool gun-it holds aluminum wire on a spool in a gun that has a mig nozzle on it.the aluminum wire is too soft to run thru the mig hose.i used 1 on some aluminum diamond plate-it worked good.i am just going to use steel mandrel bends for my ic.

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Guest Phil1934

AL wire requres a lot more heat than steel. Your typical Lincoln 170 is not going to do a good job with it and the gun is as much as the welder. As to using steel wire, you can't even clean AL with a wire brush that has previously been used on steel! I've welded .080 AL with flux rods, but I'm sure your IC is half that. However, like little SS items I need welded, a welding shop will charge a small amount and do it right.

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Guest Phil1934

Even with blue lenses (and you can't buy cobalt blue anymore as not enough UV protection), it's just a few degrees between gas welding and dropping a puddle out. I've gas welded some AL castings, but even gas welding sheet metal is tough. Again I say give it to a pro.

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Is it possible to weld aluminum with standard ferrous wire(MIG)?

 

No, in any welding the filler material must be compatible with the base metal. Typically you would use 4043 or 5356 aluminum filler wire to weld aluminum.

 

> Also, can you weld/braze brass fittings onto aluminum?

 

Yes you can weld aluminum fittings onto aluminum tubing. You can also braze fittings onto aluminum buts its difficult because typical brazing temperatures are 800 to 1,000 degrees and aluminum melts at 1,280.

 

The MIG machine you mention above can easily weld aluminum and MIG machines do not need AC to weld aluminum properly. The only special thing you will need is a gun cable that has a teflon liner and lots of extra contact tips.

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Yup, I'd give it to a profesional. My boss has a TIG/arc welder and a MIG.. then for some reason, he also bought a spool gun for the mig. ?? Works good for filling holes in aluminum plate, or butt welding two pieces together.. but from what I heard, the thing was around $1500, and IMO it's even more dificult to get the hang of than using the TIG w/filler rod.

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Aluminum melts at around 1200 degress which means the welder has to have very low heat setting and as mentioned a very good "slick" lining in the wire feed cable because the aluminum wire is fragile and soft. tending to feed improperly for lack of strength. A spool gun actually is preferable to the wire feed cable stinger gun system. An argon mix will help. I have never tried it in my Sears "Crapsman" mig welder but good migs as Miller and Lincoln should weld aluminum wire put of a cable stinger with practice and experience. Try it!

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Aluminum melts at around 1200 degress which means the welder has to have very low heat setting

 

Not true regarding the heat setting. Because aluminum is one of the most thermally conductive metals it requires more heat to weld then comparable thicknesses of steel, stainless, titanium, nickel, etc. Despite the lower melting point, the heat is being sucked away from the weld point extremely fast. You always run a higher heat setting when welding aluminum then with steel.

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Is it possible to TIG weld it with DC?

 

Yes it is and I've done it, but there are very severe limitations. You have to set the machine up for DCEP (DC Electrode Positive) which puts 70% of the heat into the tungsten. This limits the amount of amps you can run because you'll melt the tungsten. About the minimum welding amps you need DCEP to weld aluminum is 120 amps and for that you'll need a 1/8" tungsten. Anything more then about 125 amps and you'll need a 5/16" tungsten! You get great oxide cleaning but penetration will be shallow.

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You get great oxide cleaning but penetration will be shallow.

 

That almost sounds better, because the stuff that i'll be welding is only about .06" thick. It seems if the penetration is less, then it would be harder to blow holes in it.

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There are some high strenght epoxy's out there.

 

Also there are soldering rods that claim to work well to bond different materials it is called Cronatron #53.

 

I believe you need 100% argon and AC squarewave to make a good thin aluminum weld.

 

Also I bet you could get the weld done for under $50 if you looked for a hungry weld shop.

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Epoxy could work. From my experience though, it can be brittle when it sets. I don't know how it would like the vibrations of the engine bay.

 

It's worth a shot before spending a whole lot of money.

 

I still want to learn to TIG weld though.

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