Aluminum Welding

[zackbass]

I finally got my dad's TIG welder home from the shop, and I really liked it. Just like oxyacetylene but much easier and more controlled. I welded a whole bunch of steel pieces and it all came out great, but I tried doing some aluminum, in preparation for my next mod project, and realized I have much to learn.

I got the machine set up all right, set it to AC, and used pure tungsten, and tried to lay some beads on aluminum scraps. After a while I figured out that the pieces were alloys that can't be welded with the TIG. I got a piece that I could weld, and attempted to lay some beads on it. It went well, but not great.

Hopefully I'll make some progress with more practice, but is there anyone that has experience with aluminum welding? Any tips?

[jubjub]

Only tip I have is move fast. That will keep you from burning through and from warping the metal with heat buildup.

[zackbass]

Originally posted by jubjub
Only tip I have is move fast. That will keep you from burning through and from warping the metal with heat buildup.

And therein lies the catch. TIG welding is anything but fast.

[qmul]

ok... first off the technique you described is not welding. by definition, you cannot weld aluminium. that's why aluminium parts are always either rivited together or you use epoxy resin.

[jubjub]

Care to explain that qmul?

So what am I doing then when I put an aluminum feed wire in my MIG welder and joining 2 pieces of Al together with heat?


See if this helps any zack
http://www.babcox.com/editorial/ar/ar100037.htm

[qmul]

Originally posted by jubjub
Care to explain that qmul?

So what am I doing then when I put an aluminum feed wire in my MIG welder and joining 2 pieces of Al together with heat?


See if this helps any zack
http://www.babcox.com/editorial/ar/ar100037.htm

no probs

here is some basic chemistry. aluminium is extremely reactive in open air. i know there is an oxide layer present. but the amount of heat you apply to it during welding pretty much gets rid of the protective layer. hence during the welding process, regardless of how fast you do it because it's never fast enough, the aluminium will oxidise like a *****. joining two bits of metal together by melting a another bit of metal and using it as glue is "not" welding.

[Redrum]

Hence the name, Mig welding or Tig welding. Mig stands for metal inert gas where it uses a gas to shield the weld from the oxygen. Tig stands for tungsten inert gas where it also uses a gas to shield the arc. For best results on aluminum use argon gas for the shield.
With a tig machine you can add wire to the weld for strength. Fusing is only used for aluminum where strength of the weld isn't needed and looks are the most imporntant thing. Mig welding of aluminum isn't really a welding process, Its termed spray welding..

Hope this helps..

[zackbass]

Thanks for the link jubjub. Reminds me of the cracked cast iron engine block I have been working for the past two weeks, and when I started it up it seized. Oh yeah, I had a real weldor handle welding that. The guy welds jet turbines together at Howmett (sp?).

I belive that the only shielding gas that you can use for TIG welding is argon, while MIG welding uses argon with a small amount of CO2 or argon.

Redrum, you are definetly right about the term "spray welding", it's fast but but ugly. Looks almost like some of my arc welds

[meat322]

for mig welding aluminum i used a 75-25 mixture of argon and helium

[Redrum]

75/25 blend is good for mig welding mild steel. There are other gases to use also. Such as Co2, carbon dioxide works very well for mig welding mild steel. Theres another blend called Stargon which I believe is argon, helium, and CO2 mixed together. You can use Co2 for tig welding mild steel also. To get good looking welds you need a lot of practise. I been welding for 34 years now. Theres also gas welding for aluminum but you use oxygen and hydrogen. Burns real clean and hot. Used mostly for aluminum roofing and gutters, Soffit and facia.