On Sat, 14 Jan 2012 09:39:18 -0800, mike wrote:

DougC wrote:
I am making aluminum tanks for my truck's radiator. I am planning on
using 1/8" thick sheet because the reason that none of the plastic tanks
hold up is that they flex and distort.

The only welder I have is an oxy-acetylene torch. Can I weld the tanks
using 1/8" 6061?

(What I mean is,,,, I can WELD 1/8" aluminum, but I know that in thinner
sheets the 6061 tend to crack) The tanks are about 20 x 3 x 4 inches.

I will try to get 5052 or something softer if they have it, but may be
stuck with the usual.

I can't get my head around the part you're trying to make, so this may
be off topic.

How are you welding aluminum with an oxy-acetylene torch?

There's a rod called Welco 52. Also sold at much higher price as
"miracle rod" at RV shows and the like.
It's more like soldering than welding. I've had excellent luck
fixing motorcycle parts with it.

FWIW, Welco 52 technically is a solder (the conventional dividing line
is 800 deg. F; Welco 52 melts at around 750, IIRC). It's a zinc alloy
that wets aluminum very nicely and that can solve a lot of difficult
joining problems. Anybody can learn to use it in minutes.

You just have to watch out for strength and corrosion issues. It's not
as strong as brazing or welding.

Regarding O/A welding of alumnimum, it's tricky. I've tried it but not
enough to be any good at it. There's no red color of the metal to
guide you. It just goes "shlump" all of a sudden. But it's a neat
skill to learn. A lot of airplanes were built from O/A-welded
aluminum.

And if you do more than a little bit of it, watch out for the
radiation given off by aluminum O/A flux when you apply the torch. It
will play hell with your eyes. There are special goggles made just for
this purpose.

--
Ed Huntress