Hi there! I am new here. I've been posting on cnczone for a couple of years now, but this is my first at this new "zone".
I am only recently, the last couple of years, getting more serious about welding. I want to be able to not only design things, but to fabricate prototypes.
So far, I have a Henrob, Thermal Arc 185, Miller thunderbolt with detachable leads, Lincoln powermig 140. I don't get much chance to use my tig, but I do like using it.
Recently, I had a hell of a time trying to tig a 4" long T in aluminum, .050 thick. Been kicking my butt. I melt the hell out of the material, but it oxydizes immediately. I need this sucker to look like a good weld, it's part of impressing the jerks who make decisions to move me to a better, higher paying dept. So, any suggestions...? I am cleaning the material enough, and have the amperage set to 65A.
Thanks,
Ken

tell us everything about your process and we'll see if we can help you.

TIG or MIG

what size tungsten?
straight argon, or argon/helium or straight helium?
what welder are you using and does it have square wave AC?
transformer or inverter?
do you have a pulser option?<===very helpful on thin sections of aluminum

Can you better explain the joint or upload a sketch? I'm guessing it's a fillet weld with .050" thick parent material?

safe to assume 6061?
what filler? 4043?

MC

It is 3003 aluminum. The filler is 4043. The tungsten is lanthanated (gold band) , and is 1/16 dia. I have an inverter machine, yes, square wave. yes, a fillet weld with .05 parent material on both sides of the T. I am trying to put most of the heat into the (upside down T) horizontal material, and get the vertical section to heat up and flow in. It just melts, doesn't join up, and screws everything up. Now I may be removing the rod from the cup area, and be contaminating the filler, but I thought you were supposed to be able to control the heat by where you point the gun. I am I think experiencing the arc jumping from side to side, and while I was not expecting laserpointer accuracy on controlling the arc, but to have some input as to where the heat goes would be nice.... It seems to jump all over the place.
I do seem to find it easier to weld 6061 than 3003, does that make any sense? I seem to have more control, but I need the formability of 3003, so I am stuck with it.
Whaddya think? Do I just need more practice?
thanks for listening and any suggestions,
Ken

I didn't quite understand what position the workpiece is being held in, are you welding overhead?

And yes, 6061 is the easiest to weld. And yes, keep your filler in the shielded area to prevent contamination, invites oxygen and nitrogens into the weld pool which creates popping and more likely to crack.

One thing that will help alot is if you have a pulser, turn it on and all the way up. Less expensive machines might do 10pps, top of the line machines will do 5000pps, if you have a 10pps, definatly turn it all the way up, you might want to play with the 5000pps to see where it works best. Definatly helps on arc stability, and excellent for tacking! Works best on thinner sections of aluminum.

And yea, it's difficult to explain, you just have to "feel it", 90% of TIG welding is manipulating the arc and weld pool which is learning to react to the enviroment. Welding tubing is the ultimate way to learn arc control. If you want practice controlling the heat, flip the edge up on a piece of .050 or .060" aluminum, SS or mild and weld the edge... Build up a bead without melting the edge... Hard to do at first, but you'll learn fast.

MC