tig stainless

[tigman]

I was going over some of the previous posts and have a question.Aircraft you said never weave always use stringer beads,yet if i'm correct RockyD has weaved in his last picture.I know both of you guys have alot of welding experience so could either of you explain why you can weave or why you should not.
Thanks Scott.

[Guest]

This application, a lap weld is different than what Aircraft was referring to. In my lap, the weld is accomplished by washing the top plate down to the bottom plate giving it a weaved appearance. It's good you noticed that they were different. Sharp eye!

[Mike W]

Nice pictures Rock, keep them coming. They are a good learning tool.

[George]

hey tigman

at work we are usually tig welding 18 gauge on up to 11 gauge ss 304,as far as starting the weld try to fuse the two pices together before adding wire then at the end of your bead let off the pedal and hold the torch on the weld a few seconds.something else you may try is to use the minimun amount of heat it takes to form a puddle .sometimes i have to do this to minimize burn through depending what i am welding and if i am not able to put brass behind it.

George

[tigman]

Rocky thanks for clearing that up for me.I posted a picture of my start stop and the big lump,anyone have any advice.I know it will get better with practice. Scott.

[tigman]

here is a pic without a start/stop.
both welds have been wire brushed.
Scott.

[T150]

Wow Scott! That looks great. Kudos to you from this beginner. Looks steady and fairly even to me. Are you unhappy with the bead or just the start/stop part?

If you’ve only got 40 hours experience and you can run a stainless fillet like that, I attended the wrong school.

Alan

[Guest]

Originally posted by tigman
Rocky thanks for clearing that up for me.I posted a picture of my start stop and the big lump,anyone have any advice.I know it will get better with practice. Scott.

It looks like you started to add rod before you got up to welding temperature. Are you using a foot pedal? That will give you the best results. Start your arc at the left side of your crater, then bring up you heat and travel backward to make the puddle the same size as the previous crater...then add your rod, just enough to match the size of your weld and then travel forward.
This is all done as a sweeping movement....when you get to the point that you don't have to think about it, you will have achieved. Oh yeah, the pinhole in the crater....lose it.....by backing off the heat slowly while making a small circular motion...you may need a drop of filler in some cases, too.

Now as to the weld in the post, it needs more filler wire. This is what is called underfill. The bead should be at the very least flat across the face, if not slightly convex. Either a bigger rod, or push more of it into the puddle.

[aircraft]

Originally posted by tigman
I was going over some of the previous posts and have a question.Aircraft you said never weave always use stringer beads,yet if i'm correct RockyD has weaved in his last picture.I know both of you guys have alot of welding experience so could either of you explain why you can weave or why you should not.
Thanks Scott.

Weaving with SS has to do with the characteristics of the SS itself. What will happen is that SS is loves to “suck back” (Inconel is even worse) so when you weave from toe to toe it tends to suck the metal away from the toe and undercut the toe even if you are putting in more than enough filler. You can compensate for this but you end up with more filler than you need and in 20” of weld I will guarantee at some point in that weld the profile will fail inspection or almost fail now you give me 2000” of stringer beads and I would not be able to find a single problem. I guess what I’m saying it just makes you a more proficient and consistent welder of SS.

Now Rocky was doing a lap weld and you may want a certain amount of the top plate to suck down to the lower plate and you can get away with a certain amount of weave here but it’s still not recommended for proficient reasons only. I’m not saying you can’t weave on a lap I just don’t teach it, it’s an absolute sin for butt, and fillet welds.

[tigman]

Thanks T150,I was concerned with the start/stop.The 40hrs is on SS, I probably have well over 1500hrs tig welding aluminum so I'm not new to a tig torch.Thanks Rocky/aircraft for the help and info,Rocky the machine I was using was at home and has no amperage control.I have never used a foot pedal as our torches at work are set up with thumb controls.Thanks Guys. Scott