[gamble]

I am building a round can for someone. It's pretty thin like .060. I'm going to weld a top/bottom on them.

I know that aluminum, the strength is in the bead itself. From what I've read from years back and when I ground down my aluminum welds it tends to crack a little easier. However that was years ago when I first started welding.

Can I weld a top/bottom on a round aluminum tube, thin wall, and turn down the welds on a lathe for a smooth look and still have it be equally as strong? It's some car part, so I'm sure it will be vibrating a lot.

[admin]

Since it sounds like you will only be able to weld from the outside you will be better off leaving most or all of the bead alone. If you turn it down the weld could wind up being paper thin and then will crack in service.

Best

Jody


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[Otto Nobedder]

Gamble, there's a solution to this, but it's not easy.

Your caps will have to be cut so they will fit inside the tube that will be your "can", with a bit of slop. This requires some precision prepwork. A lathe would be handy...

The idea is not to set the caps"inside", but to set them ouside with a 1/16" gap, to make an open-root corner weld. This is tough as hell to weld well at .060, but it will give you the penetration you need to machine off the surface of the weld.

When machining, cut it to a dead-sharp square, then chamfer it as little as you can get away with.

I'd weld a few coupons first, where I could examine the back of the weld, to be confident I had enough internal penetration. then I'd machine one or two and beat the hell out of it.

Just musings on how I'd set it up, were it mine to do.

Steve S

[gamble]

Thanks Steve. I do cut the top/bottom smaller than the OD of the pipe. The are about equal to the ID and just sit on the lip. That's how I've done it and it works out really well. I may give it a shot and see what happens.
I haven't a clue how to use a lathe but I'm going to learn.

[TamJeff]

Agree with Steve and is exactly the joint I use for such things. I leave three little prongs on the caps so that they are self supporting on the shoulders of the tube ends and it allows me to adjust any root gap I want, just by bending the little prongs accordingly.

[MinnesotaDave]

Agree with Steve and is exactly the joint I use for such things. I leave three little prongs on the caps so that they are self supporting on the shoulders of the tube ends and it allows me to adjust any root gap I want, just by bending the little prongs accordingly.

Now this is going to save me a lot of fit-up/tacking frustration one day.

Filed away for future use - guaranteed - thanks for posting

[Bill Beauregard]

I've got a few pieces of outside corner joints done from outside only on.062" that have a nice fillet on the inside. I don't know if I could dial it in to produce them again or not.