Thanks for your site. Great resource for a beginner tig user. One question though. In all your tutorials regarding welding aluminum you never seem to mention what amperage settings to use. Do you just watch the size of the puddle and adjust it with the pedal? Do you set the maximum amperage to the maximum suggested amperage of the electrode you are using? Ok.....that's two questions.
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I try to set the machine to about 1.5 amps for every thousandths of thickness for aluminum and then I watch the puddle to keep it the right size because as the aluminum heats up , less amperage is need to make a puddle the right size.
Its not always just size of the puddle that is important...
for butt joints and outside corner joints, you are watching for the puddle to sink a little bit so you know its penetrating.
for lap and tee joints, you are watching for the puddle to flow into the corner while keeping it the right size.
for build up of worn metal, you might only need to wet into the surface without much penetration.
AS far as amperage settings go for tig welding aluminum,
just as an example, for 1/8" aluminum = .125" = 3.2mm
I would set the amperage to around 180-190
Also, just as you mentioned, I would not set the amperage higher than the range of the electrode.
for .125" aluminum, a 3/32 or 1/8 2% thor, cer, or lanth, electrode would do the job. I really dont like pure tungsten because it does not carry nearly as much amperage as ones i listed above without balling up too much.
I prefer to weld aluminum mostly with some slight taper on the tungsten..
much thicker than, .125" and I would go up to a 1/8 electrode....again with a taper instead of a ball.
Also , I would set the ac balance to around 7 for generic aluminum welding jobs
good luck,
jody