vert up on steel

[BrokenBiker]

right, need help with vert up 4mm mild steel fillets.

i am using 2.4 tungsten and rod, 6lpm argon and a gas lens, 110 amps dcen with a 17 size valved torch. Slight push angle towards the direction of travel, adding rod to the puddle from above, and i am pausing when i add rod, as i do on flat joints, adding every 2-3mm

my problem is, the start of the weld is raised and slug like, the middle is fine and the end is just full of undercut, especially at the open end of the joint.

i only have lift arc with no up or downslope.

what can i do to even the weld out so it is consistent and good. I'm happy with the middle, it looks like an average tig weld with good penetration, just the fist inch and last 2-3 inches of a 6 inch weld are doing my head in

 

[Bill Edwards]

Use it on MMA with a 2.5mm rod?

 

[wheresmejumper]

Pic would help, but move slower at the start of run, and add rod more often for the last 1/2 or 1/3

 

[dan.taylor.1]

welds cold to start fine in the middle and too hot at the top as the heat from below rises up, can you adjust amperage to suit as you move, so start higher and drop near the top?

Dan

 

[hotrodder]

As Dan, heat rises which exaggerates heat soak. Especially if talking smallish test pieces/coupons. As weld tests often want a start/stop in 'em don't start at the bottom and work you're way up. Backstep the weld i.e. weld the last bit first (where there's no more material for the heat to rise into) and then go from the bottom up. The other way of dealing with it is to vary travel speed

 

[BrokenBiker]

cheers guys. Will try moving slower at start and faster at end.

cant use mma as its arkward to get rod in because of other brackets in the way. Have a stubby back cap on tig torch so much easier to get in.

will try dipping more rod if it starts to flatten out and undercut too much thanks

 

[BrokenBiker]

well, job done. Not perfect looking but plenty strong.

also ended up tig a few bits together for my father. He is making some lean to frames to act as a tunel over his garden path, but cut the angles wrong. Ended up trying to fill. 9mm gap with a buzz box. I cut some bits to fill the gap and tig'd them in instead. By far my.favourite process, just so bloody hard to master