[chubbysautocenter]

I'm getting a little porosity on the outside corner joints. i used a flap disc to grind smooth. i believe that maybe i have embedded something in the material. how can i fix?

[Otto Nobedder]

My gut reaction is to dress the joint down (nearly through) with a hard stone in your grinder (aluminum specific), dress it with a file, and put a fresh cap on it.

Flap-wheels will do a fine job, if you use a fresh one and work it gently. Too much pressure, and the binders that hold the abrasive to the disk tend to transfer, and it's hard to get it all off with solvent. It's a case of, "be patient, and let the tool do the work."

This may not be your issue, but I've experienced it before.

Steve S

[chubbysautocenter]

My gut reaction is to dress the joint down (nearly through) with a hard stone in your grinder (aluminum specific), dress it with a file, and put a fresh cap on it.

Flap-wheels will do a fine job, if you use a fresh one and work it gently. Too much pressure, and the binders that hold the abrasive to the disk tend to transfer, and it's hard to get it all off with solvent. It's a case of, "be patient, and let the tool do the work."

This may not be your issue, but I've experienced it before.

Steve S

I was at a fab shop today, and the guy said after I work the aluminum with the flap disc, he said to use a mag cleaner and etch it. he said it takes out all the impurities. what do you think?

[Otto Nobedder]

My gut reaction is to dress the joint down (nearly through) with a hard stone in your grinder (aluminum specific), dress it with a file, and put a fresh cap on it.

Flap-wheels will do a fine job, if you use a fresh one and work it gently. Too much pressure, and the binders that hold the abrasive to the disk tend to transfer, and it's hard to get it all off with solvent. It's a case of, "be patient, and let the tool do the work."

This may not be your issue, but I've experienced it before.

Steve S

I was at a fab shop today, and the guy said after I work the aluminum with the flap disc, he said to use a mag cleaner and etch it. he said it takes out all the impurities. what do you think?

Overkill. You're not building a nuke plant.

Most people I know spend far more time cleaning aluminum than is required. The trick is not to leave residue behind from your cleaning method. Dress it with a fine enough grit stone or flap-wheel that a coarse wire-wheel will destroy any evidence that you touched it with a flap-disk, and weld it up.

Steve S

[Otto Nobedder]

I'm going to HAVE to start a thread on my next aluminum repair.

The "surgical clean" idea is growing old and wearing thin.

Steve S

[chubbysautocenter]

I'm going to HAVE to start a thread on my next aluminum repair.

The "surgical clean" idea is growing old and wearing thin.

Steve S

ok got it thanks

[GreinTime]

Lollol Steve I feel like you just made him tuck tail and run away. That last post comes off as kind of harsh.

--Sam

[Otto Nobedder]

Lollol Steve I feel like you just made him tuck tail and run away. That last post comes off as kind of harsh.

--Sam

Oops.

That "surgical clean" comment was meant to be an "aside" on the subject, not a harsh response to his friend's suggestion of etching the metal. I suppose the earlier comment about "not building a nuke plant" may have overemphasized my point.

The etching will likely work fine, but adds labor, and etches outside the weld zone, affecting the finish. I suppose if the tank will be embedded in foam, etching the entire tank may be of benefit. I just think it's more than what's needed to make this porosity fix.

If I came off as harsh, I apologize. It was not my intent.

Steve S

[winston weldall]

I'm going to HAVE to start a thread on my next aluminum repair

please do!

mike

[AKmud]

College professors constantly preached relentlessly cleaning aluminum to us during our TIG class. I was just discussing this with my LWS owner and he also says too much emphasis is out on cleaning for 90% of aluminum jobs. He only hits things with a wire brush if the pieces are visibly dirty and never uses chemicals.

[rake]

When digging out porosity or other such defects I've always leaned towards a carbide burr
in a die grinder whenever possible. The chips fly out and you don't leave any adhesives behind.

[DonaldE]

When digging out porosity or other such defects I've always leaned towards a carbide burr
in a die grinder whenever possible. The chips fly out and you don't leave any adhesives behind.

Yeah, YOU are absolutely rite Rake, but how could we manage this???