Aluminum TIG help

[matts427]

I have a 180 SD and have quite a few questions, all concerning aluminum. First, no matter where my ground is, how clean the material is, my arc starts are extremely eradic. (sp?) I use pure electrodes, and have found that the best way to select Tungsten size is to use the smallest tungsten that doesn't "spit" the tip. (or create a ball that's too large) I've tried flooring the pedal instantly and ramping power up slowly, but nothing has helped. The HF is working, and after the arc starts, it runs fine.

Next question concerns material choice. I'm planning on building aluminum sumps, tanks, pans and valve covers, and from everything I've read, 3003 H-14 seems to be the alloy of choice, using 1100 filler. To weld 6061 bungs, fittings and brackets to the 3003, it's suggested to use 5356 filler. Does this sound about right? My AWS filler chart supports these filler choices (for ductility) but I'm allways looking for a second opinion.

I have another concern about alloys... I have a friend who is going to bring me a Moon style spun aluminum fuel cell, and I'll be heavily modifiying it. The ends of these cells are 1100, while the bodies are 3004. Can anyone tell me what the difference between 3003 and 3004 is? Does the filler choice remain the same?

Last question. Well, more of a request. My butt and lap joints are looking ok, but fillet welds are lacking. I've attached some pictures of a few lap welds and a fillet. Please tell me what I'm doing wrong!! I've read that you can use 2% With a blunted point for fillets to get a smaller bead with more control. I haven't tried it yet, but what do you think?

Thanks in advance!
Matt
P.S. Please forgive me if the pictures don't work... I'm computer illiterate!

[matts427]

Ahh, I see...... okay, here's the second picture

Second Picture

[matts427]

Third picture

third picture

[cope]

Matt, you might also post over at the Hobart forum. They are closer to real time and you will find a nice bunch of people. Not necessarily auto racers, but there are a few.

http://www.hobartwelders.com/mboard/

[ASKANDY]

Matt,
By the looks of your pictures, you are doing OK. You can try a Ceriated or Lanthanated tungsten sharpened (not to a pinpoint). It will focus your arc a bit better and will not form as big of ball end. It should start easier too.
Make sure you are using pure Argon. A Arg/He mx or pure Helium will start harder.
As for you material question, 3003 is great because of it's easy to form and weld. You can use the 1100 or 4043 for filler. The 6061 can be done with the 5356 as you stated or 4043 as a second choice. I would use the 4043 for the 3004 to 1100 joint

A-