[PSUBS-MAILIST] Aluminum Welding Technique Question

[Steve McQueen via Personal_Submersibles]

Here is the video series (2 parts) I was referring to that mentions the
"ball" technique:

https://www.youtube.com/watch?feature=player_detailpage&v=ZWJt3fFJ6Hk

Anyway I was able to get my tack weld done after several times. It was also
older, pitted Aluminum (I did wire brush it clean).

Steve


On Tue, Apr 22, 2014 at 1:49 PM, Alec Smyth via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> 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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