[PSUBS-MAILIST] Aluminum Welding Technique Question

[Alec Smyth via Personal_Submersibles]

Hmmm, I was unaware of the "ball" technique and did not do that at all.
Which is not to say it isn't a good idea, I just don't know. I do recall
the tungsten forming a little ball on its tip, but I was not switching to
DC+, and in fact the reason I remember it was because I think I spent a lot
of effort trying to grind off the little ball before just giving up because
it would happen all the time!

The current I think will just depend on the mass of the pieces you are
welding and the thickness of wire. Start small and dial up as necessary, or
just set it high and use the pedal to control it.

The one thing I do remember was the main challenge I ran into. Aluminum is
a very good thermal conductor, but absorbs very little heat. Therefore, the
problem is when you are welding a little thing to a large thing. Lets say
you are putting in X amount of heat (as represented by the current
setting). Both pieces start absorbing heat, but the little piece can melt
before the big one has even puddled on the surface. In that case, try
adding a heat sink of some sort to the little piece. For instance, bolt it
to a steel plate. What you need to do is let the little piece conduct away
more heat so the big piece can puddle. If you are welding similar-sized
pieces, it is not very hard, but welding little aluminum tabs onto a big
chunk of aluminum is tricky.

Hope that helps, I'm definitely not an expert when it comes to aluminum
welding.


Best,

Alec


On Tue, Apr 22, 2014 at 11:49 AM, Steve McQueen via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> I attempted some Aluminum welding this weekend.  I needed to tack 2
> together pieces of a trolling motor mount I modified for my stern thruster.
>
> I watched a video that said it is important to first first strike an arc
> on DC+ for a few seconds to create a "ball" on the tungsten tip prior to
> going back to the AC mode.
>
> It was unclear in the video if the arc was being struck on an Aluminum
> piece or the Steel welding table surface.  Does it matter?
>
> Also they said the amp range should be set to 55-75.  Seem OK?
>
> Thanks,
> Steve
>
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