"Bruce" wrote in message
...
On Tue, 3 Jan 2012 11:13:20 -0700, "Bob La Londe"
wrote:

"Bob La Londe" wrote in message
...

We are getting a little off topic aren't we... LOL. To bring it back on
topic, I just welded in a patch on that boat.

Had a buddy that bid on a job to repair some rental boats; lot of
welding. Got the bid and went out and stick welded them all, at a rate
that others had bid for TIG welding. Said the owner got made about it
:-)

I didn't know it was possible/practical to stick weld aluminum. I do it
with a MIG machine and straight argon gas. One of my buddies has a more
expensive pulse MIG, and he can weld about twice as efficiently with it.
Certainly its faster than TIG.


I really hate welding flat aluminum as it warps so bad.

There are tricks. I'm just a hack metal sprayer, but the big one is to make
lots of spaced tack welds when joining sheets and then work back and forth
fill between the tacks, so you aren't building to much heat in any one area.
A pulse MIG is more forgiving in this area, but alas I just have a regular
MIG. Another trick for some problem spots is to stack tack welds. It looks
like it was welded with a TIG that way. The big thing though is brushing
off the oxidized coating with a stainless brush and cleaning any oil off the
metal with alcohol or acetone. Getting back to Pollard. Lots of people
will weld aluminum on a backing of some kind, but I don't know anybody who
welds, back chips, and back welds like he suggests except on some odd
positioning of thicker plate. Back chipping and back welding some of the
thinner stuff commonly used in small boats just isn't practical. I think it
would do more damage than good.