MustardCat

The problem I'm having is that the inside of the tube doesn't fully fuse. There always seems to be a gap/crack.

For example:









Some things I've tried so far:
Adding a 45° bevel to the tubes.
Waiting for it to keyhole slightly before adding filler. (Got out of hand quickly.)
Trying at 75, 85 amps and moving very quickly.

Welder setup:
65 max amps and using foot pedal
120hz freq
30% cleaning
No pulse
#7 cup
1/16" 2% thoriated tungsten ground to a point
1/16" filler rod (4043)

The tube I'm using is 1/16" wall 6063, cleaned and brushed.


I did try varying the frequency and cleaning % as well but I was having the same problem.

If anyone could share what settings are working for you I would appreciate it.

Luserkid

Although it could be done, try to avoid keyholes when you weld aluminum. Your better off with the pieces butted together. If you get a small line down your penetration that could be bur or non fused material from being a cold weld with to much rod pushed. For 1/16" this is how I would setup my machine.

150 amps (you said you have a foot pedal so use it to control the heat, I suggest blow a hole then know that thats your limit on pedal and heat)
200hz
70% Pen/30% clean
#4 cup @ 20cfh
3/32" tungsten (grind how you like, I rarely notice a difference until I go .040 aluminum, but make sure its not contaminated)

Dont be afraid to give aluminum some heat until you get used to it. Thats the best way to learn penetration in my book. Also try flat plates first so you could work torch angle.