Tig question from a rookie

[Ram48]

I'm new (as in never ever tigged) and after I replace the fan that I broke on my 250ex I want to tig the seams on an aluminum Battery box I will be bending up while waiting for the fan to arrive. The material will be .040 3000 series sheet what settings should I start with?
I will most likely use 2t or 4t on the torch sw.as it seems a bit less complicated then a foot pedal right now Can I fuse it or do I have to use filler rod? The good news is I have plenty of extra material to play with. I also intend to practice on sheet metal before commiting to aluminum. and pointers and ideas would be helpful
Ray

[performance]

Ray,
I would always keep some filler close at hand for this, especially if you burn through, you will need some assistance.
Here's what I would do:

Set the AC freq about 100 or so. Set the Balance around 30%.
Set preflow for about 2 seconds for the smoothest start. Start amps about 10, upslope 2 seconds, Welding amps about 30. Down slope about 3, end amps about 15. Post flow for about 5 seconds.

[jakeru]

3003 is supposed to be pretty hot crack resistant, so you might find luck in welding it autogenously (without filler rod.) If you wanted to try that, a very good joint configuration for autogenous welding is as pictured. Bend the ends of the weld seam together to give you some material that can melt back and fuse together. A joint configuration like I have pictured (shown for welding thin (.020") copper sheet) would work well, I'll bet. Travel speeds on a joint like this can also be very high.

If you do a more traditional joint using filler rod, 4043 would be a good choice. .040" is some pretty thin (challenging) material to learn on. I welded some .020" aluminum recently and although I can do it, it was pretty challenging, need a stable arc start and low-amp operation, which seems to be a lot about grounding, tungsten grind and cleanliness. To me .065" seems like a walk in the park. .040" is just a matter of practice. As the material gets thinner, finer hand manipulations of the torch and filler rod are necessary.

Taking the time to make a tight weld joint fit-up and getting it properly tack welded is also important; expect to spend time learning that as well. Hope this helps and best of luck!

[geezer]

Why not use your mig on that project, after all mig welders were invented to weld aluminum and 040 wall should be no problem for your mig.

[Ram48]

Why not use your mig on that project, after all mig welders were invented to weld aluminum and 040 wall should be no problem for your mig.

Geezer I was under the impression that Mig for aluminum was only for the thicker material. But then again I admit I don't know a damn thing. I'm sure someone will come on to either confirm or deny what you said.
I do have a spool gun for my mig and some .023 or.030 wire so I could play around with that also.

[geezer]

Geezer I was under the impression that Mig for aluminum was only for the thicker material. But then again I admit I don't know a damn thing. I'm sure someone will come on to either confirm or deny what you said.
I do have a spool gun for my mig and some .023 or.030 wire so I could play around with that also.

YES you are correct .040 is way too thin, my mistake. I was thinking something around .125

[Ram48]

YES you are correct .040 is way too thin, my mistake. I was thinking something around .125

Thanks "G" you saved me some time a aggravation by letting me know mig could not be uses on.040

[Wookie]

I'm new (as in never ever tigged) and after I replace the fan that I broke on my 250ex I want to tig the seams on an aluminum Battery box I will be bending up while waiting for the fan to arrive. The material will be .040 3000 series sheet what settings should I start with?
I will most likely use 2t or 4t on the torch sw.as it seems a bit less complicated then a foot pedal right now Can I fuse it or do I have to use filler rod? The good news is I have plenty of extra material to play with. I also intend to practice on sheet metal before commiting to aluminum. and pointers and ideas would be helpful
Ray

I would use some filler autogenious welding with alum tends to crack out