Bad Argon, bad materials, bad operator?

[false_aesthetic]

Folks,

I've been working on a frame with a "lugged" ST cluster. Noticed that when I welded (yes, I mean TIG) the TT to the lug it the weld would pop + spit a little bit. Seemed strange to me. Nothing crazy ugly with the weld but I don't usually experience that kind've thing.

I prepped like I normally do:

2% Lanthanated Tungsten sharpened on a "blue only" wheel.
Wipe rod with acetone. Usually Weldmold
Outside + inside of tube is sanded.
Wiped with clean acetone.
Re-sand.
Re-wipe.
Same thing with the ST lug.

____

Today I was welding the SS to the cluster and I started getting a LOT of popping and spitting. Ugly bead. Porosity. Blew through at one point.
Same prep. Tried ER70S (made sure to clean that too). Looks similar to welding hot-rolled steel w/out cleaning off the mill scale or when you forget to open the argon bottle.

Checked the hose. Checked the lens. They're fine. CFH ~25.

Things that I think it could be:

1. Me / prep.
2. Argon. It's a new tank.
3. Lug.
4. Dunno, fill me in.

1. If it's my prep, what else do I need to be doing? I've never experienced this before even when I've bought crap metal from our local supplier.

2. If it's the argon. I guess I just take it back and what? Ask the shop to test it? Is there a way to test every time I get a new bottle?

3. The lug is a Ritchey Break-Away. I'm removing the casting marks and scale with emory (To quote Jody, "Shiny bright steel."). Wiping down 2x with acetone (and using a clean cloth).

4. Other thoughts?

[Andrew R Stewart]

The question I have isn't related to the welding happenings- why weld a lug? All the lugs I've known of are made to be sweated with a capillary action filler (brazing).

Have you tried to weld on a different piece of steel without changing anything right after the problems? Andy

[armyofevilrobots]

I just had a similar experience with a bad bottle. All you can do is bring it back and ask them to purge and refill...
Also check for a leak in your shielding line. A small leak can sometimes pull a bit of air in while it flows.
Oh, and if you've moved your workspace around, the welder's cooling fans might be messing with your shielding if they can blow air near your work (had that happen welding something beside the weld cart last year).

[Amaro Bikes]

Your Argon is fine, it's the cast lug

[false_aesthetic]

The question I have isn't related to the welding happenings- why weld a lug? All the lugs I've known of are made to be sweated with a capillary action filler (brazing).

Have you tried to weld on a different piece of steel without changing anything right after the problems? Andy

Andy, maybe lug isn't the best word. It's the top of a Ritchey Break-Away system.

I did try running a pass or 2 on some other steel and while it wasn't popping, the welds were coming out a bit grey.

Your Argon is fine, it's the cast lug

Aimar, the production Ritchey Break-Away bikes (steel) are TIG. Do I need to alter my prep in some way?

[VertigoCycles]

If you think it's the welding setup (including argon) weld on something else and see how it goes. Change one thing at a time until you figure it out. Don't assume any part of your setup is OK until you figure it out. You're using 25cfh with what size orifice? How clean is your tungsten? Has it ever been dipped and did you grind it until you stopped seeing orange sparks?

[edoz]

Anything cast is notoriously crappy to weld. Are your results the same on other joints without a cast fitting involved?

[false_aesthetic]

They're not porous but there was popping and spitting on some Nova + Dedacciai tubing. But I haven't had a chance to get back to the shop and run things through detailed testing.

Eric, do you have an idea of how the factory making the Ritchey break-away frames are getting decent results TIGing? Seems like the Weldmold and ER70S-2 wasn't liking things.