Al 6g tig

By Lawrence (*****)

Date 07-07-2010 20:58

Welcome to the Forum Pam

Alcohol and Acetone are preferable to MEK in my opinion.. Acetone leaves the least residue.

Pipe is perfectly clean.... Inside, outside and very important.. The faying surface (root faces)

Brand new wire brush.... Assuming these are test coupons and have never seen anodize... the brush and wipe really ought to be enough... All prep should be right before welding... that oxide begins to grow back at once.

Perfect electrodes... Even the suggestion of contamination from a previous dip and you can forget the X-ray.

Hydrogen porosity indications are common enough if travel speed is slow or for some other reason heat buildup is too great.. Hy is soluable in the molten alum and after too much is absorbed it will not all exit as the weld cools, leaving a grainy appearence on the weld face.

Increased travel speed, and try the largest filler wire you can handle in order to take advantage of the cooling effect of a filler with more mass.

53 amps tells me you are prolly welding a thin wall tube. If your tungsten can handle it you could try backing down to 55% balence.

By pamthewelder Date 07-07-2010 21:32

nice to meet you lawrence,

i will try increasing my heat and speed, i do move pretty slow. i will back my balance down too. thanks for the tip!

pam

By Lawrence (*****)

Date 07-07-2010 22:44

Pam

Sounds like you military... Thanks for your service!   I'm an OLD Navy aerospace guy.

If time permits I would suggest getting plate of the same alloy and thickness... Prep same as pipe... But.. If you are using a root opening you might try No gap if the alum is under .063.

Work on getting the root appearence you like with a consitantly improving face appearence.. Smooth is good, grainy is bad, shiney is great on the face but ONLY if the root penetration is acceptable.

increasing heat is good.. Aluminum likes hot and fast... But but but!   This takes alot of practice.. Which is why I suggest trials on some plate.

Since you describe balence in percetages I'm assuming you are using an inverter power supply... If yes.. You might get some improved results at AC frequency of about 180-220 Hz...   Arc is more directional and narrow for sure...(which means torch angle must be perfect) Some say contaminants are stirred away too.. but I'm skeptical about that... Frequency above 220 will just trigger headaches and make your coworkers annoyed.

By pamela weiler Date 07-08-2010 22:51

Hey Lawrence,

I am Air Force :) My supervisor is ex-Navy. It's funny, I didn't ask for this job but here I am one of the better welders in the job. I already passed stainless, inconel, and titanium. Everyone said aluminum was going to suck. I changed my balance and increased my heat and speed. Lat night, my bead look better and one would have passed except there was porosity in the tack welds. I need to use less filler on the tacks I think. I have been using MEK and wire brush cleaning for now. You think acetone is just as good? Once I get this cert I get my 5 level which I must have to be eligible for E-4!!!

By 803056

Date 07-07-2010 21:00

Are you wearing clean gloves while feeding the filler metal into the puddle?

Did you wipe down the filler metal with a clean alcohol soaked cloth?

Once you degreased the material with alcohol or MEK, and wire brushed the joint with a cleaned stainless steel brush, and draw filed the groove faces with a cleaned Vixen file did you by any chance handle the material with your bare hands? Or perhaps you ran your finger down the joint to make sure there were no burrs?

Do you have a liquid cooled torch? Are the valves functioning properly? If not, you could get some condensate around the collet which will flash into steam when you strike the arc.

It is time to play the part of the detective and run down all the possible culprits.

Best regards - Al

By pamthewelder Date 07-07-2010 21:34

I do clean the filler rod and try not to touch the tubes with my bare hands. I do have a water cooled torch so condensation might be possible so I need to investigate this further. Thanks for the tip Al.