[RichardH]

It's a habit of mine to pick a difficult project as I'm learning, and TIG is no exception... I'm making a small wireframe structure out of ER70S-2 filler rod, with 1/8" for the frame and 0.045" for non-structural areas.

I'm trying to fusion weld this, using 0.040" tungsten. Spot welding or gas brazing would probably be better choices, but they're not the techniques I'm focusing on right now.

Surface tension with steel is enough to quickly ball up the 0.045 about 1/16" back from the joint, so it's taking some finesse. I've had good luck pulsing 5/10A to weld up bits of 0.045 to each other, but it takes at least twice that to get the 1/8 to puddle. I had hopes of puddling the 1/8" and getting enough heat transfer through the fitup to melt the thin rod, but I'm not seeing that - perhaps more current would do this.

The struggle I'm having is how to direct the arc between parts in a tiny joint. I have to move the torch a significant distance before the arc will jump over, making it really tough to keep both parts wet long enough to bridge them.

Any good tricks to directing the arc when doing fine work?

Cheers,
Richard

[AKweldshop]

Needle sharp tungsten and prop the cup technique might work.
Try different torch angles, it might direct the puddle in a good way?

Good luck,
~John

[GreinTime]

What about just holding the wire in the position that you want it to be in and just hitting the pedal?

[RichardH]

What about just holding the wire in the position that you want it to be in and just hitting the pedal?

Yeah, parts are laid out in position (not trying to feed the wire into the joint). I'll toy with a higher-current quick-tack. To John's suggestion, I'll also try a much sharper tungsten with the pulsing.

Cheers,
Richard

[Braehill]

Richard, since you said it was wire you're working with maybe you could leave the .045 part a little longer than needed and use what melts as your filler. Just trying to get a mental picture of what you're making. A picture of these joints might help even if you don't want to reveal the whole project maybe a mock-up joint could give us an idea of what you're doing.

Len

[RichardH]

Richard, since you said it was wire you're working with maybe you could leave the .045 part a little longer than needed and use what melts as your filler. Just trying to get a mental picture of what you're making. A picture of these joints might help even if you don't want to reveal the whole project maybe a mock-up joint could give us an idea of what you're doing.

Now, that's a clever compromise on melting back the wire. I'll have to give that a try.

No problem posting pics. I didn't think it was interesting enough to need one.

I had better success before with just straight 20A when I did a mock-up with 1/16 and 1/8, but the .045 is proving a bit touchy.

[RichardH]

Here's a test piece I made using stock from my local metal supplier's K&S rack. It's sold as "music wire", and this piece is 3/32" on the top and bottom rails, and 1/16" on the verticals.

Wireframe Test.jpg (37.18 KiB) Viewed 650 times

K&S' website lists the alloy as "Spring tempered, phosphate coated, carbon steel wire ASTM A228". Not my first choice of material, but the only thing they stocked in that thickness. It welded OK at about 20A and no pulse, but became too brittle in the HAZ. For the most part, this alloy / thickness didn't ball up too badly, except at the one joint in the middle bottom, where I had to add filter to bridge the gap.

Moving forward, I tried the next round using TIG wire as the material, switching to 1/8" and 0.045", just to make things interesting. Maybe a bit too interesting. I might just need to step back to the 3/32" and 1/16" sizes, but using filler wire as the material instead.

Cheers,
Richard

[Superiorwelding]

Richard,
Sounds like a fun project to me! I have not welded ASTM A228, but actually did a SS project almost identical to what you are doing. I don't recall all the exact specs, but I can remember that I sharpened my 3/32" tungsten to a sharp point and focused the arc on the thicker matl. When the thicker matl melted I dabbed filler into it and bridged the gap while melting the thinner matl and was good. I was using .035 SS mig wire as filler. This might be one of those posts where a video would help the best. I hope this made sense and hopefully it helps.
-Jonathan

[RichardH]

Richard,
Sounds like a fun project to me! I have not welded ASTM A228, but actually did a SS project almost identical to what you are doing. I don't recall all the exact specs, but I can remember that I sharpened my 3/32" tungsten to a sharp point and focused the arc on the thicker matl.

It's fun so far. A good excuse to try something new and stretch my skills. If I'd had my head screwed on straight, I would have used filler rod in the first place, but I mentally didn't consider it a "material".

I gave a go this morning with a needle-sharp 0.40 tungsten, and higher amps, but the arc really wants to stick to the puddle. Trying to redirect it just 1/16" away is tough, because it'll just "stretch".

I'm going to play with better fit up, in hopes of pulling the puddle from the thicker rod across the joint to the thin rod. This last round I've been snipping the wire with diags instead of a grinder like I did the first time. I think that may be stopping heat from transferring from the thick rod to the thin rod to get the puddle to bridge over. With this stuff, there's no applying pressure to tighten the joint - the entire wire is liquid and it'll deform. You have to coax it.

Cheers,
Richard

[Otto Nobedder]

My preferred method for joining 3/32 wire to 1/8 or bigger wire, Is to set the welder for 200A at the panel, and use the pedal to "On/Off", position the tungsten very tight to where the wires meet, and "tap" the pedal for a short burst of high power. I don't wear a hood for this, I just close my eyes. It works for me 95% of the time or better.

For .045, maybe set the machine at 50-80, and use extra length, as also suggested ealier?

Steve S