Tig 102

[mitch_04]

So, I've read this entire thread and still haven't gotten better at TIG welding, what a crock.


Oh, you are supposed to practice as well? Hmm...


Anyways, I've just started TIGing with my main effort being sheet metal for body work. I'm trying to cut down on the weld finishing and warping. Any tips along those lines?

[GregWeld]

Originally Posted by mitch_04

Anyways, I've just started TIGing with my main effort being sheet metal for body work. I'm trying to cut down on the weld finishing and warping. Any tips along those lines?

Yes --- Practice a lot and learn how to get better with a hammer and a dolly...

[Vince@Meanstreets]

Originally Posted by mitch_04

So, I've read this entire thread and still haven't gotten better at TIG welding, what a crock.


Oh, you are supposed to practice as well? Hmm...


Anyways, I've just started TIGing with my main effort being sheet metal for body work. I'm trying to cut down on the weld finishing and warping. Any tips along those lines?

It's all in the prep and procedure. You will get better with time.
I have my prep together that I can put a patch in with no filler and very little finish work. This is after years of practice.

Get a few older scrap sections of the same thickness you will be doing and play with it. You'll find that it's all in material placement, fitment and heat control. Also try different temps and tungsten point sizes.

I run a low temp and a super sharp point on my tungsten.

picture is a patch on my old nova project. gap was .010 in, 4 tacs and no filler.

[mitch_04]

I have been using 1/16 tungsten and filler, but it just doesn't seem quite right. I think the rods too big, tried some twisted up MIG wire (all we have is .030 wire) which was better.

I would like to try the .040 and .030 tungsten and filler, seems like it would be easier to control the heat. I have been practicing on pieces of sheet metal (16 & 20) and, while this sounds "cocky" it's not, it went very well and almost seemed easy. Didn't burn through, decent pattern, worked the way I hoped it would.

Fast forward to trying it on the car. A '78 Trans Am I'm restoring for a customer. Tried it on a quarter skin and couldn't lay a bead to save my life. Grabbed the mig and decided I would practice on my own project until I got better. Unfortunately, it will be a while before I have time to do more "real" practice on my pickup. I'm very good with MIGing on sheet metal, but I still get those little "dents" from warping. Was doing short tacks and tapping in between, letting it cool... just hoping the TIG will help out a big.

I'm trying to explain what I am trying to learn a little better, but the pain meds I'm on from my surgery are making it difficult. I'd appreciate everyones techniques and specs on their sheet metal welding. Tungsten, filler, and gas cup size, amperage ratings, and pulse settings (if you have them).

[Ketzer]

I've been at this off and on for several months and just not making headway. Too much heat or too slow speed or just poor technique. I went over and got some hands on lessons on a buddies machine (similar to mine just his is older) and right out of the gate I was getting nice welds, good penetration, etc. I have been afraid to blame my machine because I acknowledge being a beginner. Turns out my machine may have an issue.


Jeff-

[GregWeld]

Originally Posted by Ketzer

I've been at this off and on for several months and just not making headway. Too much heat or too slow speed or just poor technique. I went over and got some hands on lessons on a buddies machine (similar to mine just his is older) and right out of the gate I was getting nice welds, good penetration, etc. I have been afraid to blame my machine because I acknowledge being a beginner. Turns out my machine may have an issue.


Jeff-

That's interesting. Wouldn't it pee you off if all this time you thought you stunk and it's the machine!


There's some good info videos about the correlation between travel speed and heat. Most "newbs" automatically think they should turn the heat down and slow their travel speed…. and that actually puts more heat into the piece.

The "masters" (which is NOT ME) can crank the heat up and pick their travel speed up and have a far smaller HAZ (heat affected zone). I've done this - and it works - but you have to have mastered the torch and fill pretty well in order to pick up the speed.

[GregWeld]

So since some of you guys are trying to weld some pretty thin sheet metal -- here's something you might FORGET to do in this process….

#1 - your fit up will make or break the whole job. Poor fit = poor welding


#2 - a GOOD welder can deal with sloppier fit - but beginners -- trust the rest of us - spend your time on making your parts FIT CLOSELY.


#3 - Tack your work in the proper order. Yes - there is an order. If you tack the piece in the middle - your corners will pull out of shape…. put too much heat on the corners and your middle will bow etc. So of course there's about a hundred an fifty eight gazillion ways to do things - but I like to tack up the corners first. Then the middle - then in between the corner and the middle.

NOW HERE'S THE PART YOU WILL FORGET - when in the heat of battle (is that a pun?)….. USE YOUR FRIGGIN HAMMER and tap those edges back in to place!

What you'll see is that while the square might still be a square - and still "fit" the square hole (if that's the shape of your patch or whatever) - it will have moved IN AND OUT of that hole so there's still a gap - but the gap has opened off the "flat" -- so you need to massage that back so the pieces are matched up on the same plane. If not - you'll burn thru the high edge.

We're talking MINUTE -- that's MI NUTE -- here -- but remember that if you're working with sheet metal - this is thin stuff to start with. Sheet steel is measured in 1000th of an inch. 18 gauge is .050 -- 19 gauge is .0438 ---- 20 gauge is .0375

If you're "gap" has moved off plane --- 20/1000th --- you're not only going to have a difference in the off plane metal to deal with in your finish work - your gap there is just that much more to try to weld as well. It's these very small things that we "forget" when we're new and we're so focused on just running the torch and all that.

[Sieg]

^^^ Keep in mind that is from an Internationally Licensed Pyrotechnician that was trained to blow stuff up.

Well said GW.

Ketzer.........there was a time I was willing to bet big money my machine was defective. Honestly I was hoping it was defective, but.........