FINALLY got to use a TIG today! A few Q's

[DusterRT]

Well, it finally happened! Something worthy of me coming out of lurk mode for, lol. I've been looking forward to trying TIG out for a long, long time. I had a guy run me through the setup of the machine the other day but I pretty well just sat down on my own for a few hours today. This is at the mini-formula shop at my school (SIUC), a couple of the guys are fairly experienced but no resident experts are on hand..anyway.

At first, it was really weird. Not point and shoot like the MIG! It was frustrating at first but I'm starting to get the hang of it (and am glad the grinder is near by for the frequent trips to clean off the electrode). I think I've found a couple things that would give me problems though..

1. I'm welding on .080" wall 4130 tube. I'm told this isn't the easiest stuff to weld..or is it just not the easiest stuff to weld correctly?

2. The filler rod I used for 98% of what I was doing was 3/32" 4130. IIRC, isn't stainless ideal for 4130? And it's way thick..I wasn't too sure about this until I dug around and found an 8" piece of 1/32" rod with "ER70S-2" (stainless?) and proceeded to lay down some extremely impressive beads as compared to what I had been doing. There was some thicker mild steel laying around that I put together with the thick rod and it came out really well. Is this more the change of material, or the thickness? I also tried some .025" MIG wire but it was too thin for what I was doing (it was melting before I could get it to the puddle).

3. The guy who showed me how to set up the welder suggested the gas be set to 35 CFM. This seems pretty high to me, I think I saw TIG-God Matt say he used 15 CFM somewhere?

4. Anyone want to reccomend some welding gloves? The ones we have are bulky, and expecially with the filler rod, make things harder to control. On the other hand, it doesn't take long for that torch to get HOT! I think I now know why people are so big on water cooled units..maybe I'll just get a leftie..

Well that's all I've got for now. I'll get some pics soon if anyone would be interested in critiquing my work..and thanks for any input!

Travis

[Matt@RFR]

Travis, congrats on the new experience. A tip: Cut your tungsten in halves, and sharpen both ends. Do that to 3-4 sticks, and you will be able to weld for awhile until you've gone through all the prep'd tungsten, then go sharpen all of them again. After you have more practice, you'll be grinding tungsten less and less.

1. Chrome Moly itself is not any more difficult to weld than mild steel, it's just different. (that's what I say about stainless too) It requires less heat input than mild steel, and subsequently requires a very short arc length. The two things that are most difficult to learn.

.080" isn't the best to learn on, either, but won't be impossible. Same with round tube. You're doing this the hard way! If you can, find some 1/8 - 3/16 flat bar to practice on. Thicker base metal will be a ton more forgiving with regard to heat input, and will let you use bigger filler, which most guys find easier to use when they're starting out.

2. 3/32 is WAAAAY too big for .080. Way too big. 1/32 would be called .035". And yes, that's the correct size for what you're practicing on. I use .035 filler on base metals as thick as 1/8", and sometimes thicker.

Stainless filler (Ex: ER308, ER316, ER347) is not the best filler for 4130N. Most shops that do that are only looking at the higher tensile strength potential of the weld, but are turning a blind eye to the lack-luster elongation percentage potential. (Meaning it doesn't like to bend) Depending on the intended use for the weldment, ER70S-2, ER70S-6, ER80S-D2 are the most common, with ER80S-D2 being the closest match to 4130N's tensile numbers, while still retaining good elongation percentage potential*. Using stainless filler isn't the choice of well-read fabricators, and is just plain expensive.

There are occasions when 4130N filler is used, but it is required to pre-heat and post weld heat treat (anneal) the weld and the HAZ, or the weld has a good chance of being extremely brittle.

(* I say potential because elongation percentage, when talking about a weld zone, is defined by the amount of dilution between base metal and filler metal, as well as the joint design, and the weld parameters used.)

3. You recall correctly. 15cfh is a good catch-all starting point. 35cfh is way too much, and can cause excess turbulance, which can pull atmoshpere into the gas stream and contaminate the weld.

4. Tillman kid skin gloves are the industry standard.

4a. Yeah, air cooled torches do get hot, although it should take quite awhile to get hot when welding .080 steel. You should only be running around 60 amps. The second (and more important to me) reason everybody likes water cooled torches is that they're half the size of an air cooled torch. Once I used a water cooled torch, the next time I picked up an air cooled torch, I felt like a one legged retard trying to swim. I refuse to even touch them anymore.

4b. Pictures!

[toxicz28]

I felt like a one legged retard trying to swim.

THAT is hysterical!!!

[Matt@RFR]

So I'll be meeting you in hell too?

[toxicz28]

So I'll be meeting you in hell too?

If the wife gets her wish, I'll be waiting there for you. I guess I'll hold the door open for you.

[DusterRT]

Got a little more time in today. Brought my work home and took some pictures..



This is some exhaust tubing I cut for something, and then decided to use something else. So it got put back together. On the left, I used no filler. On the right was my 3rd bead with the lovely 3/32" 4130 rod (all we have at the moment). I'm having troubles working the photos here so each one will have its own reply..critics, fire at will..

[MrQuick]

Matt=show off, Jake = suck up..heeee heee j/k....i have a question but will start a new thread.