Welding Tips and Tricks

I’m having a problem. I’ve been practicing my aluminum TIG welding by making cubes out of aluminum sheet For the second time now I can’t seem to be able to fill the very last spot. I mean the last spot that would seal the cube up. I keep getting black soot trying to fill the very last spot, like there’s some type of contamination. I’m wondering if it has something to do with the exactly the fact that I’m sealing the trapped air. For some reason it’s interfering with the Argon?

The reason I’m thinking this is this is the second time this has happened. On the first cube exactly the same thing, the very last spot would not fill. I cleaned, removed material, cleaned again several times with the same result each time. I chalked it up to contaminated material. Now the same exact thing is happening with a completely different work piece.

Any ideas?

I'm posting a picture just so you know I'm not talking about a huge hole.
Thanks for any help,
Paul

I beleive you are going to have a small relief hole somewhere for the expanding gasses inside to escape.

pro mod steve wrote:I beleive you are going to have a small relief hole somewhere for the expanding gasses inside to escape.

Yeah this is what I'm thinking. I was just wondering if there was some way to get around that.

genarr3 wrote:

pro mod steve wrote:I beleive you are going to have a small relief hole somewhere for the expanding gasses inside to escape.

Yeah this is what I'm thinking. I was just wondering if there was some way to get around that.

Ice it down then use the quick tack method to close the hole. I did that with some some short closed end tubes.

i did tig welding stick welding and oxy-acetylene welding in highschool, one thing i remember distinctly was that with oxy-acet and stick welding they were very firm in saying they didn't want us to ever weld a closed container. not sure if this was because of explosive dangers or what just remember that was a strict rule they had. We never did tig in highschool but there was a machine there so i used to jump on it all the time, maybe you arent in danger welding a closed container with tig but it won't heat up enough on the inside to puddle? not sure but i know the oxygen inside outside ratio had somethin to do with why they were so strict on this concept. if you ever do oxy-acet and turn the oxygen down you'll get that same black soot on your weld material.
theres my 2 cents

BurninRod wrote:i did tig welding stick welding and oxy-acetylene welding in highschool, one thing i remember distinctly was that with oxy-acet and stick welding they were very firm in saying they didn't want us to ever weld a closed container. not sure if this was because of explosive dangers or what just remember that was a strict rule they had. We never did tig in highschool but there was a machine there so i used to jump on it all the time, maybe you arent in danger welding a closed container with tig but it won't heat up enough on the inside to puddle? not sure but i know the oxygen inside outside ratio had somethin to do with why they were so strict on this concept. if you ever do oxy-acet and turn the oxygen down you'll get that same black soot on your weld material.
theres my 2 cents

I don't have any real need to close this chamber really, I just hate it when the puddle doesn't do what I want.

put some argon inside. and weld it with higher amps as fast as you can.