Finishing off

[wilbur]

Hi all,

I'm teaching myself tig - and am gradually getting to a weld on steel which doesn't look too awful.

I often notice an odd effect at the end of a weld, where there's some kind of defect/inclusion/whatever which I think forms at the point the arc cuts-off.

Here are two different welds showing the same effect:

This is using the torch switch rather than the pedal. There's 1.2s of taper on the welder and 3s of post-flow. There's often a little click/spit as the arc goes out, which is I think when the mark appears.

I tend to reverse-up a little as I let go of the switch, and I don't think I'm stuffing the tungsten into the pool or anything really daft.

I don't think it's a postflow problem because I think it happens before that stage. I've played with the down-slope time a bit without seeming to make much difference - but I guess that's the secret somehow.

Any suggestions?

 

[Brad93]

Not enough taper off nor enough post flow. You need to back the weld off slowly to stop craters,

Also your metal is not clean enough.

As you are tapering off you need to move the tungsten to the edge of the pool or wiggle it.l

Try 3 seconds down slope. 5 or 6 seconds post flow and hold the torch until you hear the gas stop flowing.

 

[wilbur]

Not enough taper off nor enough post flow. You need to back the weld off slowly to stop craters,

Also your metal is not clean enough.

As you are tapering off you need to move the tungsten to the edge of the pool or wiggle it.l

Try 3 seconds down slope. 5 or 6 seconds post flow and hold the torch until you hear the gas stop flowing.

Thanks for these - I'll give them a try. I do always move back up the weld out as it's down-sloping.

The metal was cleaner than it looks in the photos, it's picked-up a load of crud from the bench between the welding and the photo.

 

[Richard.]

Really nice job I can see the top run was running quite a bit hotter.
Yes you need to clean your metal up nice and bright and a little practice on the end of the run but in all its a lovely job.