TIG in acute angles?

Need a bit of advice. I'm welding 4130 and presumably will move on to other high-carbon steels of more expensive varieties at some point. I'm having a lot of trouble getting welds in the acute angles formed by junctions of multiple tubes - we're talking about perhaps 45 degrees. I can't get a decent pool to form, and I can't seem to get a fillet going regardless of how much rod I add. I know practice will help, but it'd be easier to do so if I knew what I was trying to accomplish better - can anyone help?

Materials:

4130 cromoly tubing, 1 1/8"-1 1/2" diameter, .035"-.049" wall thickness.

Welding setup: Miller 150STH, amperage control via pedal. Coarse amps ~50. Argon @ ~30 cfh. #5 cup, 1/16" electrode

Should I go to a smaller cup? Extend the electrode further beyond the cup? Give up and cry myself to sleep?

Thanks, guys!

-Walt

Reply to
Walt Wehner
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does "coarse amps~50" mean full pedal to the metal is 50 amps? would think that to be a bit on the lite side...

30 cfh seems like an awful lot of flow (you outside, in severe draft, or??) ever wonder about pressure coming off the regulator (around 10~15 lbs or so??)

some one else may be providing more distinct factuals; wouldn't worry/wonder about shedding tears....

Reply to
dogalone

You want a smaller tungsten for .035" - .049" like 0.040" lanthanated or thoriated. Also probably want skinny filler like .035" ER80S-B2.

If you use a gas lense, you can stick the tungsten out further (1/4") and use less gas (12-15 cfh).

You might also try raising your amps to around 65A if you are doing a fillet on the .049" material.

How do you like that welder?

Jeff Dantzler Seattle, WA

Reply to
Jeff Dantzler

While on a tour of Robinson Helicopter several years ago, I was surprised to see they use a stickout of at least an inch and more like 1 1/4 to get inside of those tight angles of chromoly. They had a special home made gas lens but you should be able to get close to that stickout with commercially available lenses. Fillet welds take practice any way you do it. Here's a picture:

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last torch on the bottom right has a cup shaped like a bell. Imagine a cup like that only flipped around so the large end is toward the work. Stick some scotchbrite like stuff in for gas diffusion and pull the tungsten waaaay out.

Reply to
Zorro

I don't do this well, so I'm looking for help too. What I currently do is weld the acute angle by welding along the flat section, getting the puddle well established and working it towards the acute section. I do it in two stages, basically from each side towards the center of the angle. I use as much stickout as I need, and increase the gas flow to compensate.

to see they use a stickout of at

chromoly. They had a special home

commercially available lenses. Fillet

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The last torch on the bottom right has a cup shaped like a bell. Imagine a cup like that only flipped around

for gas diffusion and pull the

Reply to
Brian

Switch to gas lens collet bodies so you can slide that tungsten out far enough to get in there.

Reply to
Ernie Leimkuhler

Ernie Leimkuhler wrote in news:200220041254349010% snipped-for-privacy@stagesmith.com:

Why or when would you NOT want to use a gas lens collet body? Wondering why they just didn't come standard equipment on TIG torches. :-)

Reply to
Marty Escarcega

they're a tad bulkier (esp. in the smaller sizes)

Reply to
dogalone

My feelings exactly. Actually when we got our 2 brand new Lincoln Squarewave 175's at school a year ago, they both came with gas lenses. I was impressed.

However I do not start students off with gas lenses. I like to wait until they have enough torch control to be trusted with that much tungsten sticking out of the cup.

Reply to
Ernie Leimkuhler

You could add two gusset plates on the outside of the tube at those restricted joints and not weld where you can't get . Or you can try to place some tape around the joints to keep your inert atmosphere from diluting thus enabling you to have a longer stick-out . I've never tried oven bags but you might not have too much heat to work with . If you get a ceramic cup that has never been use you can grind it to enable you to fit in deeper . You can get your tungsten red hot then bend it some too A hard thing to do is to not keep adding heat to get a weld started . You shouldn't need more heat to weld different degrees of fillets . You have to get TO the joint then heat it up enough for a ball of filler to stick where you want it then have the patients for the puddle to form then the control for the puddle not to start to climb out of the joint (too much heat) . Heat is not just amperage with tig welding it is time spent in an area too . You don't have to "dip" the filler metal ,you can keep it in the puddle all the time and still get root penetration . It makes it easier not to get "suck back" too . The dangers of a fillet where you can not inspect the back side are when you melt trough the thickness and starve the puddle for metal . This is when you pull metal from the cross section of a joint to fill it . It takes allot of experience and good eye sight to pick up on this condition from the out side . This is not something you have control over No one does . When a puddle is starved for metal it pulls all the molted metal into it that is available . This is what causes under-cut . Your best bet is to cut open a joint so you can see inside to check for SUCK-BACK .

Reply to
Lewis Edwards

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