T joint woes!

[themininut]

I'm using 1050a h14 ali 2mm thick with 4043 filler, red tungsten, number 5 tip, inverter tig with foot pedal. I having a lot of trouble trying to do a t joint, my arc length is about 1/16 i guess. whenever i try and do a spot it just burns back the vertical ali no matter how light i am on the power, i'm pointing the tungsten into the root. I can do runs, butt joints and lap joints ok, but just having trouble with T joints.

machine setup

Tip stickout

Runs done on 6082 with 4043 filler...

Lap joint, with a little dipping!

another lap joint.

CC welcome, any advise on doing a spot and starting decent T joint would be great.

M.

 

[pedrobedro]

Have a go at an outside corner joint on the same material before you try a T, you might get nearer to the setting you want.

 

[runnach]

Red tungsten is for DC (thoriated), you require zirconiated or ceriated for al/al, although it is doable with thor.

Give joint a good clean with wire brush, aim arc more on to bottom of joint until arc is establisted and stable, T's are a dawdle, take you're time and practice a wee bit more......

 

[hotrodder]

As Runnach favour the lower piece initially if the top piece is melting back.

Other things that can result in those symptoms... if the part is sat on the table then the lower piece will take more heat due to the fact it's 'backed up'. Building the heat slowly can perversly make things worse in this situation as the heat is going to rise. Blocking the part off the table may help

Welds are pretty 'grainy' and dull. Often a symptom of too much heat (not necessarily too many amps, dawdling with less heat can also do that). Looks like you have quite a bit of AC cleaning dialled in. That can also cause grainyness especially with 4043. Run some beads on plate at different AC balance settings. Increase the DCEN balance (less cleaning) until the puddle gets sluggish and back it off a little from there. What you want is the minimum amout of cleaning necessary to produce a clean, fluid puddle without any 'bits' floating in it

 

[themininut]

The T joint I'm trying to do IS sitting on the table, I'll try lift that for starters.

The AC balance setting on this is labelled "clean area width" and is pretty much dialled out, i did test it and its the smallest area around the weld that it would do, i might try turning the "arc force" down a tad as this is making it hotter too.

I did try to favour the lower piece but i expect the vertical melted because i was dawdling around I'll try that again.

I may also have a go using the pulse feature, can't be any worse right!

Too cold to have a play now, so will try tomorrow.

Thanks guys.

M.

 

[hotrodder]

Leave the pulse alone for now, it'll just add another bunch of variables

 

[Chris_]

When trying to start the joint (and only until your a little practice) Heavily favour the lower piece. As soon as the surface starts to melt add a little filler, then push the arc over into the joint and up the verticle peice. As soon as the surface of the verticle piece starts to melt, add a little filler. Then run the arc back and forth between the two puddles so that they start to come together, add filler as needed to make sure it doesn't melt back to much. Eventually they will join and you can start to move along the joint.

The first couple of times you do this will produce a large messy start to the weld but once you have the idea you can tidy it up.

Cheers
Chris

 

[themininut]

The first couple of times you do this will produce a large messy start to the weld but once you have the idea you can tidy it up.

cheers matey, will try that next time i have a pop. I did have another go and did almost that but still didn't quite work out. I can get nice beads on an outer corner weld now.

will post up some images of my effors (blobby mess) next time i have a go.

M.

 

[Dave Richards]

Not much consolation this my friend but you are attempting one of the most difficult joints there is, fillet in aluminium, we use this joint to test new employees.

 

[themininut]

Managed to get an hour or so to play today, and the results are...

I found that if i started with lots of power to get the puddle in the horizontal piece then dabbed some rod in there it got me going and i could then drop off the power a little to keep the puddle moving.

thanks for the help guys, just need to practice a little more now and i'll be happy.

M.