Runaway TIG Puddle

[malich]

I was practicing tonight with the new 1% Lan. tungstens I got and I was welding 1/4" fillet welds with 230A, 1/8" Tung, Gas Lens and 3/32" 70S-2 filler.

I noticed on some welds (usually on the smaller test parts) the puddle will start extending way past the tip of the tungsten like about a 1/4". I tried lifting off the pedal but that only cooled the weld and did not seem to help.

Any ideas? I tried adjusting the torch angle back a bit, same problem. Could this be happening because my test parts are too small and they are just building the heat up with no place to go?

I did run two very nice beads on the same material only the pieces were larger and no problems.

Thanks in advance!

[Mark...]

Did you make sure that when you sharpened your tungsten that the grooves created by the grinder were running in the same direction as the tung.? In other words the grind marks should run parallel and not 90degrees to the tungsten. If not the arc may want to jump off of one of the small ridges that the grinder leaves instead of the very tip.

[David R]

Originally Posted by malich

I was practicing tonight with the new 1% Lan. tungstens I got and I was welding 1/4" fillet welds with 230A, 1/8" Tung, Gas ...Snip..... Could this be happening because my test parts are too small and they are just building the heat up with no place to go? Thanks in advance!

Yep.

David

[TubularFab]

230 amps on small parts sounds like a lot of heat... How small is small?

[gnm109]

Originally Posted by TubularFab

230 amps on small parts sounds like a lot of heat... How small is small?

Maybe a bit too much gas and heat as well.

[TSOR]

The angle that you sharpen the tip will effect the width of the puddle.


Long point = wide puddle

short point = narrow puddle

[Supe]

You may start at a given angle, but be increasing arc length and torch angle as your progress.

[malich]

The test parts were actually two parts that were 2" x 3" matting the 2" side for the fillet. I was going to weld one side and do a bend test.

I did have the parts sitting on top of some other parts I had welded, but the old parts had very little surface area where the test parts were sitting.

The tip was fine because I had welded some 3" x 3" fillets earlier and it worked great,

The tip was ground correctly and was a shorter tip, about two times the tungsten width and it worked fine on the 3" x 3" fillets.

I was not using the whole 230A and I held the angle and tungsten width the same as the larger test parts. The problem happened everytime I welded the 2" x 3" parts and not the 3" x 3".

The filler was not overloaded, still trying to learn to actually fill the joint on the fillet welds.

I kept just enough heat to make a puddle about a 1/4" in width, the problem starts when I am about half way into the joint so I am thinking it is a heat related issue especially because the parts I was setting on top of were useless for dissipating much heat.

I think I need to place the parts on my welding table next to to draw the heat out.

[David R]

Back off on the heat as you go. You only need enough heat to keep the correct size puddle. Try a smaller puddle and thing about it getting hot as you are going. A faster travel speed will help too.

David

[OldSparks]

You really don't need all that heat. Example....to weld a tube with a 1/4" wall thickness, I would use about 120 amps. This would pass x-ray and bend tests. Your fillet joint would have more metal area than a butt joint but you should only need about 130-140 amps. You must be flying at 230 amps with 3/32" filler. Do you know that the Miller Tig Calculator says to use 3/16" filler at higher amperages.

[malich]

Hi Old Sparks,

I am not using the whole 230A, I only have the pedal around half way, just enough to make a puddle size of 1/4" and wet in. I will try turning down the heat to see if it makes a difference in controllability.

My welding chart from Lincoln shows to use a 3/32" filler with 1/8" Tung on 1/4" MS. I know those charts are not 100% accurate, but the 3/32" filler works good. I still cannot get enough filler in the joint yet. I am getting closer, but need more practice watching the back side of the puddle which is now what I am trying to learn.

Thanks for the post!

[David R]

My book says for 1/4" T joint , in a grooved fillet, 4 passes, 3/32 tungsten, Electrode angle, 45* , Electrode tip diameter, .045, Amps 60 - 130, 1/16" filler, Travel speed 8-10 ipm, 1/2" cup, 15-25 Cfh.

Time your self and check travel speed.

I only use 15* to 20* torch angle. I guess I am going to have to try 45*.

David

[malich]

Hi David,

The books says 4 pases, that's why they may require a smaller filler and tung. I did read on Diamond Ground, for thicker tungstens and thick material to use a tip angle from 25 - 45 deg. because it produces more penetration.

I did a test with a 1/8" Lanth. tungsten with the short 25 -45 degree angled tip and a longer 12 - 25 deg. tip in which I just formed a puddle and ran it for 2 inches on 1/4" flat stock MS and it appeared that the shorter 25 - 45 deg. tip blistered on the backside more.

Maybe you can follow up with some additional test?!?!

Thanks!

[David R]

I did. My conclusion is just sharpen it. I go for 2*d, but don't worry about it. I do put a small flat on all of them red, gold and orange I don't use pure. The gold ones seem to sharpen easier, and I do a lot of that.

http://www.weldingweb.com/showthread.php?t=19177

YMMV

David

[weldbead]

marc...about the grooves--ideally to get them really in line with the tungsten you'd want to grind on the outer edge of a large radius wheel where the chords would most approach a straight (minimal curve) line..is this only theory, or can you get a bad grind by using too small a wheel and get curved grooves?

[malich]

I grind my tung on my belt sander pressing against the backing plate for a perfect grind each time. Only takes about 10 seconds and done!

I also use a dedicate belt for the tung since I have an extra belt sander.

[weldbead]

what typre of abrasive on the belt? cant use aluminum oxide..

[malich]

Originally Posted by weldbead

what typre of abrasive on the belt? cant use aluminum oxide..

Just a standard 80 Grit Resin Bond belt I got from Grainger. The arcs are always nice and clean. I am thinking part of my problem may have been moving too slow or a slightly wrong angle or arc distance.

I had the problem happened again with the puddle and started to move a little faster and changed the torch angle and I think the distance and the problem went right away. I just am not sure what was the actual cause because I did 3 things all at once so I could get the weld done.

I will keep working on it.