I can’t weld this aluminum

[Janderso]

Dang it.
I picked up these aluminum strips in the local scrap yard to make a coolant tank for my surface grinder.
I was ready to begin tacking the corners and found a surprise.
I darn near gassed myself. It gives off an ammonia smell, turns black and bubbles/pops when I heat it up.
I used an angle grinder with a flapper wheel and acetone with no change in the properties. Yes the argon is on.
Maybe I can use some high tech silicone and brackets to hold and seal it.

 

[benmychree]

Must be made of unobtainum ---
I have written a friend who is quite into welding weird stuff asking him what it might be, will LYK. Aluminum might not be a really good choice for a coolant tank, as coolants are a bit caustic, and will corroded by it.

 

[Ed ke6bnl]

Could you have bad gas? I have had bad gas at the end of the bottle

 

[DHarris]

Dang it.
I picked up these aluminum strips in the local scrap yard to make a coolant tank for my surface grinder.
I was ready to begin tacking the corners and found a surprise.
I darn near gassed myself. It gives off an ammonia smell, turns black and bubbles/pops when I heat it up.
I used an angle grinder with a flapper wheel and acetone with no change in the properties. Yes the argon is on.
Maybe I can use some high tech silicone and brackets to hold and seal it.

that may be 7075 - T something if it is, that is aircraft grade and machines well but does not weld. I don't know how to "test" to tell what type of aluminum it is. you might ask on the welding / casting section of this forum.

 

[Janderso]

Let’s see, I could braze it, epoxy it, I have some amazing RT at work we use on Diesel engine.
Oil and diesel doesn’t seem to bother it.
Choices, choices.
What would you do?

 

[Janderso]

Could you have bad gas? I have had bad gas at the end of the bottle

The tank has about 80% left, I haven’t had any problems with it to date.
I like the way your thinking though. When I saw that black and the popping I immediately checked the gas flow..

 

[Aaron_W]

Weird, waiting to see what experienced TIG welders have to say.


I did find this googling TIG welding aluminum black soot, so maybe using a different filler rod alloy might work. Don't know what you were using.

Q: Why do I get so much black soot on and around my welds when I use 5356 GMAW wire to weld 6061T6?
A: The black soot actually is magnesium oxide. Magnesium content in 5356 is high (up to 5 percent). Some common base materials, such as 6061, also have relatively high amounts of magnesium—generally 1 percent.

When magnesium is vaporized by the arc’s heat and comes in contact with oxides, black soot forms. A proper gun push angle of approximately 15 degrees helps keep gas coverage at the leading edge of the weld pool, which reduces soot. Your shielding gas should be pure and moisture-free.

Clean the base material with a stainless steel wire brush, and use the correct weld parameters for the wire size to minimize overheating of the weld puddle. If strength is not the most important consideration, 4043 filler wire can be used to reduce soot in this application.

https://www.thefabricator.com/thewe...-welding-qa-about-soot-porosity-and-equipment

 

[Old Mud]

Let’s see, I could braze it, epoxy it, I have some amazing RT at work we use on Diesel engine.
Oil and diesel doesn’t seem to bother it.
Choices, choices.
What would you do?

IMHO I would make a S load load of shim stock out of it and try again with different stock. Of course that would after i have tried that gas with other known types of aluminum.

 

[Janderso]

IMHO I would make a S load load of shim stock out of it and try again with different stock. Of course that would after i have tried that gas with other known types of aluminum.

You know, it took about 30 minutes to cut these pieces with my plasma cutter.
I should just start over and do it right.
Otherwise, I’m dealing with a coolant leak, oily dirty water, fun fun.

 

[HarryJM]

The tank has about 80% left, I haven’t had any problems with it to date.
I like the way your thinking though. When I saw that black and the popping I immediately checked the gas flow..

Have you tried welding some aluminium that you have welded in the past just to verify your gas/etc is good?