I have aluminum wire for my MIG-welder. I tried welding some aluminum tube to an aluminum flange, but the weld came out terrible. I used 75Ar/25CO2 gas. I'm trying to make some air filter pipes for my twin turbo Camaro. Someone told me to use helium ( isn't that for heli-arching). I guess I used the wrong gas. It would be desirable to have a gas that sheilds for stainless, mild, and aluminum. I'm a 19yr old beginner welder, but my turbo headers, downpipe, and exhaust turned out great.

 

you need 100% argon, and a decent amount of power. What welder are you using?

 

you'd want a teflon liner, .010 or so larger tip, argon shielding. i've used little miller 110v welders for nickel and aluminum with good results. if you really do much you'd want something like a cobramatic feeder or a spool gun. for what you're doing i think you'd really want to use GTAW (tig) instead of wire

 

The aluminum needs to be very clean. Grind where you want to weld or clean it with acetone. You should also be using 100% argon.

 

I have the Dual MIG-131 by Chicago Electric, It uses 110v ac.

 

Trouble with the cable feed welders is that they don't push aluminum wire very well through the cable. A better way to weld aluminum is with a spool gun. That way the wire is being pushed only a couple of inches before it exits the gun.

 

yep 100% argon and a spool gun, we have a lincoln power mig 300 at the shop set up with a push pull gun and teflon liner and it is amazing, i can lay out stuff that is just unbleiveable, of course i would personally tig it since i am extremely exp. in tig

 

I know nothing about welding other than stainless steel. Where do I get the spool feeder thing for aluminum wire? What prices should I look for. Whats a teflon liner (sounds like something with low friction). My welder seemed to push the .030 aluminum wire justfine even at high feed rates (I tried every combination of speed and heat to get it to weld, but no luck). I know I need 100% argon sheild. Could I use a teflon liner with the standard attachment?

 

If you have pushed alluminum wire sucessfully then just get the argon bottle and give it a try. A spool gun is pricey around 500 bucks if memory serves.

As in everything else there is the preffered way and what you can get away with. You have an inexpensive 110v welder, i don't think your going to be doing any production work! But you should be able to get it to work for your purposes. I did quite a bit of alluminum welding with a HD weldpack. No liner, no spool gun. Just argon and CLEAN wire. Make sure there is no oil anywhere on the drive rollers, many welders come setup with a felt oiler for steel welding applications. Normally you would have to change the gun liner if there was oil. since you have evrything you need except argon, swap your c25 bottle for argon and give it a try. Let us know if your successful.

 

you'd also want to not intorduce carbon into the base metal by using a steel wire brush, get a stainless one.

 

if you start welding an area them move to another one and then come back you should brush the old weld with a stainless steel brush, never use a mild steel brush on aluminum, also if you have trouble with pitting you can also use helium it sheilds better than the argon but only use on aluminum

 

Only 1 reply mentioned AC. You need to have the welder on AC for sure.

 

You have to reverse the polarity of the MIG machine when doing Aluminum.

You CAN use mixed argon/helium for MIG alum. The mixture of gases disguises the bad charateristics of each and is perfered over straight Argon because the combination of helium helps with wider penetration and hotter voltage.

You should also use as mentioned the teflon liner and a good trick is to use a slightly larger tip than the wire you are using. (ex. .025 wire and .030 tip)

 

My MIG welder says to switch the ground and hot wire when using flux-cored wire compared to sheilding gas for ferous metals. Is that the same as switching the polarity? The two posts that I switch are labled + and -. I had enough luck with the aluminum, straight argon, on the shielding gas setting to weld my brother's valvecover to clear his alternator. I could not successfully weld an aluminum canister on the AC system in my dad's van.

 

Yes, the + and - are the polarity.