TIG welding

[CamaroAJ]

what causes the tips to burn off so fast, turning the pulse off helped but it doesn't really matter what i have it set at i'll make a point and it just melts away. also where should i put the balance control at? i know my problem is me and not knowing how to set this thing up and i have some info commingmy way about TIG welding classes around here.

[Matt@RFR]

AJ, Please fill in the following:

-machine (sounds like a dynasty)
-gas mixture and flow rate
-cup size
-tungsten alloy, size and stick-out
-machine settings
-material alloy and thickness
-material prep
-what does the tungsten look like when this happens, exactly?
-tungsten prep

[CamaroAJ]

I'll take a look when i get home, all i can remember is a 1/8 tungsten about 1/4 inch out and a 7 cup, 1-3/4 roll bar tube, 7-15 psi of CO2,argon mix, preped with a grinder with a sanding pad. when it melts sometimes it will make a big ball on the end or turn into a round tip. i'll see if i can get a pic or two and mail them to you. i asked a few fab shops around here and they don't want to offer any help because i'm not giving them any business by doing it myself, so i posted on here cause you guys know your ****.

[Matt@RFR]

Wrong gas. You need either pure argon or argon/helium, which is more expensive and you don't need it. CO2 will NOT work with TIG.

7cfh of argon is WAY too low. You need to start at 15 if you have a gas lens, or 18-20 with standard collet bodies.

You need to use 1/16" tungsten or maybe 3/32" if it's the smallest you have for that tubing. Also, do not use pure tungsten (green band)...use 2% thoriated (red band), thoriated (brown band) or ceriated (grey band) for steel.

You don't need the pulser! Turn it off and take time to learn it AFTER you get the basics down.

You should be on DC-, NOT AC for steel. On DC, you won't have the adjustable balance, so that's another thing to forget about for now.




Now, this is going to make me sound like a real asxhole, but take it for what it is: Constructive critisism, not an attack on you.

You're doing almost everything wrong. On roll cage tubing. PLEASE tell me this is PRACTICE tubing, NOT a structural part of a motor vehicle. You are obviously in need of much practice.

Attached is what your welds should look like before you get anywhere near structural welding.

[sanddan]

Matt,
How much does cup size affect the different settings? Is there a good "rule of thumb" for how far the tungsten should stick out past the cup? How about hints for getting started on aluminum? Thanks
Dan

[CamaroAJ]

this is just stuff laying around i'm welding on, i know i'm real bad with a TIG but i bought it to learn and thats what i'm doing, i was using the mixed gas because i had it for use with my MIG. everything i was told about from a welding supply was wrong then, i am taking notes on what your saying and so far i'm already progressing. is the cup size ok or would you recomend another size? as far as welding on the car i'm MIG welding everything, learned to do it about 5-6 years ago so i'm more that conifdent in that. Thanks for all your help Matt.

[Matt@RFR]

Cup size only effects gas flow rates and tungsten stickout. With a bigger cup, you may have to up the flow alittle, and the opposite is true with smaller cups. Generally, you can get away with more stickout with the larger cups, and especially if you're using gas lenses.



Picking cup size (all sock-in-the-pants-jokes aside) is dependant on access to the joint, joint design and weld size. For instance, a butt joint in 1/2" Titanium will require a #10 cup or bigger, (all other gas coverage devices not withstanding), but a butt joint in 16ga stainless will only need a #4. Fillet joints tend to create a bit of a chamber for the gas to collect, so you can get away with a smaller cup. I use a #7 cup for almost everything. For what I do, the only time I change is to go smaller to gain access in tight joints.

Stickout is a funny thing. All the books say that you should use no more than 1.5x the diameter of the tungsten. (3/32 x 1.5 = just over an 1/8 stickout) Try that sometime, and see how sore your neck is after an hour of arc time! I usually use 1/4" stickout, and I think you'll agree that there's nothing wrong with it. It all depends on how good your gas coverage is, which includes gas flow, gas quality (purity), breezes in your shop, arc length, and how steady a hand you have.

Like I said, I'm usually at 1/4" out, but have gone as far as an inch with no problems on extremely tight chassis welds. For something like that, you'll definetely need to bump the flow up, probably in the neighborhood of 25cfh, and having the torch pointed down will be a big help. (Argon is heavier than air) I once had to do a repair for AeroJet, here in California on a stainless rocket fuel somethingornuther, and it was so tight that I took the cup clean off of a 50 amp water cooled torch, purged the cavity with a second bottle of argon at like 40cfh and had at it with no problems. The tungsten must've been hanging 3" out of the collet body.

If you're running too much stickout and/or too little gas flow, the tungsten will start to turn colors (contaminate) and sizzle or just plain blow off the end, and the weld will have porosity. Your tungsten should be the same shiny silver it was when you started. Another cause of tungsten contamination is too short post flow times.



As a side note, I heard someone the other day talking about how much less sparks he gets with his TIG over the MIGs he uses at work. If you get any sparks while TIG welding, you need to clean the material more. That goes for any smoke left around the weld. (ofcourse, brown sooty smoke means you need to quit dumping the tungsten in the puddle.) You should be able to TIG weld naked.

[KendallF]

You should be able to TIG weld naked.

Aside from the funny tan lines.. I keep sun-burning my arms because I'll weld with short sleeves and short TIG gloves on. The TIG emits UV and to be safe you should be wearing long sleeves and gloves. (Yes, I will probably ignore my own advice tomorrow, if not sooner)...

[Matt@RFR]

That's the beauty of it...no tan lines! See?

You know, sunblock actually works for keeping arc burns to a minimum.