Anyone here decent at Tig welding aluminum?

[daniel_buck]

The intake manifold of my diesel engine needs to be modified a bit to best accommodate the turbo. Basically, I want to cap off the original intake location, and drill a hole and weld in a short piece of tube mid way down the main intake tube.

the main intake tube is round, so the smaller tube that is welded to it needs to be notched (like a roll cage tube) before it's welded.

I can provide a sketch of what is needed, if that would help.

Anyone here Tig weld? If it were steel, I'd already have it done myself, haha! But it's aluminum :-(

[inVERt'D]

I TIG weld, but I'm not set up for aluminum. Besides that, welding cast aluminum can be a bit dodgy because of porosity, impurities, and I imagine the grain.

Depending upon how hot it will get, I could recommend a good aluminum brazing rod which I've used a number of times. They claim it's stronger than welding (seems so in my experience), better for cast aluminum repair than TIG, and produces better results on things like cylinder heads.

[daniel_buck]

learn to tig aluminum darn it!!


Oh, I did cut off a bracket from the rear of the intake manifold, and it seems to be quite solid, I don't notice any air pockets or porosity. Unless you're talking about molecular stuff, I'm fresh out of microscopes :-\

[inVERt'D]

One day I hope to learn to stack dimes on aluminum, but the problem is my equipment. I basically have two TIGs, and they're both DC output only. The surface of aluminum oxidizes more or less immediately, and that oxide has a significantly higher melting point than the base metal. By the time you melt through the oxide, the base metal could be falling out. To deal with the oxide, you need either AC TIG/ Argon or DC TIG/ UHP (ultra-high purity) helium. I have looked into the latter--even the uncertified UHP is very expensive these days.

A friend of mine owned an aluminum foundry for many years and had a lot of automotive aftermarket clients like Edelbrock. He used to TIG weld castings that had repairable defects, and got very good results. It can definitely be done, but there is the potential for complications that can make a mess. Castings can vary widely in quality. Probably yours is good stuff, but aluminum will smear on the surface when you cut it.

Another option would be to MIG it. Personally, what I've seen of AL MIG welds hasn't impressed me a lot. I've seen what seems to be an inordinate amount of cracks through and adjacent to them that seem to be related to relatively minor defects. That's what I love about carbon steel--cheap, very weldable, and very forgiving.

[flatout]

How thick are the pieces? I have a smaller tig and could do up to 1/4 thick.

[daniel_buck]

I'm not sure how thick the pieces are, I would guess around 1/4" or less. I'll know for sure when I drill the hole, I'll let you know Fred, thanks!

[RAT]

If that is the manifold that came with the engine you should get it high pressure or ultra sonic cleaned to remove the fuel, dirt and oil that tends to soak into the casting. Then take it to Fred and let him TIG it. I have an AC mig and pure Argon and can weld it for you, but the TIG on good clean metal is better. TIG can burn deeper into the base metal than MIG in most cases cause the temperature is controllable and you can run many passes if needed. Ya gotta haul ass (relative to TIG) with a MIG gun.

[daniel_buck]

hm... I didn't think about cleaning it! I guess aluminum needs to be super clean to tig?

How would I go about high pressure or ultra sonic cleaning?

[RAT]

Look it up. There are places right by you that do ultrasonic. Too bad I don't have my old shop still. Had a big USC there... It shouldn't cost too much for one part. If it does, and alternative is to go to Homo Depot and get a couple gallons of Acetone. Pour them is a container large enough to hold the part completely submerged and let it set for a day or two with a top on it or the Acetone will evaporate. Then take it out and set it in the Sun for a few hours to dry out. If you scrub it, make sure you use a stainless steel brush. SS won't recontaminate the aluminum like steel does.

[daniel_buck]

right on, I'll look around for a place to get it cleaned

[daniel_buck]

I contacted a few places local to me, and they all said they couldn't do it without destroying the aluminum. Not sure why.

Anyone know of a specific place that can do this? Even if I have to ship it out

[Toolman]

Lloyd's in Redondo Beach may be able to help you. They welded my gas tank for me.

[inVERt'D]

If you use the brazing rod I have in mind, you won't need to do more than wipe it down with acetone and make it shiny with a stainless steel wire brush. You can use a MAPP gas bottle with a Turbo Torch. The melting point is about 750* (pure AL is ~1200).