On 16 Sep 2003 09:56:21 -0700, (Craig Suslosky)
wrote:

I recently bought a Lincoln 110V 135 Plus mig welder. So far I love
the machine. It works great for what Im doing. I was curious if anyone
has tried welding alum. with one of these. I would like to weld some
1x3x11ga. alum tubing. Does anyone have any experience with this? Any
help would be great. Has anyone gas(oxy-acet) welded alum? How does
that work, I read somewhere that you need special lenses. Thanks for
the help,
Craig

Another poster said he had acceptable results on 1/8" aluminum, and 11
gage is pretty close to that.

A problem I've had with my Lincoln SP-125 Plus that essentially made
me regard it as unusable on aluminum was that it's "pusher" wirefeed
mechanism just doesn't work well with aluminum wire. The wire
bends, jams and is generally a huge PITA. I even used the teflon
liner. Keep the run from welder to torch as straight as possible
and use the hardest Al wire you can get. I don't recall the alloy
numbers anymore but Ernie or a welding store could advise you on that.

I gas-weld thin aluminum (under .060") as my preferred approach.
11-gage would take a fairly large tip but would otherwise weld very
nicely with gas. Gas is a lot slower than MIG, though, and it'll
leave a much larger HAZ (heat affected zone) if the aluminum was
heat-treated.

You didn't mention what aluminum alloy. Some alloys are a lot easier
to weld than others. A very rough rule-of-thumb I use is that if
it's "white" aluminum or "soft" aluminum it'll probably be easy to
weld. If it's gray or hard (as 2024), it may not be so easy. I'm
a hobbyist, by no means a pro weldor. Who knows what mystery metal
we've happened upon as rawstock, right?

You definitely need special lenses for welding aluminum, to block the
bright sodium flare from the flux. Otherwise you can't see the
puddle. You need to see the puddle to make decent welds.

I really like the TM2000 goggles from
http://www.tinmantech.com/
but they are a bit pricey. If mine got broken I'd replace them in a
heartbeat, but I've heard there are others that also work and cost
less.

Learning to weld aluminum with gas does take significantly more
practice than learning to weld with MIG. It's easy and fun once you
get the hang of it, but it takes a while to get there. .