I had heard stories but I knew it was a necessity. Looking back it shouldn't have been that difficult but trying to learn it on my own without someone in person saying "do this... don't do that" definately made the learning curve much steeper than it needed to be. My biggest frustration was that one minute everything would lay nice and then I would pick up the torch 20 minutes later and I would lay out a pile of crap. Not being able to figure out what was causing the contamination was mind bending.

I was pretty good with a MIG but with all of the intercooler tubing I was doing I knew I had to learn TIG. Fortunately the intercooler tubing on most of my projects get the black texture treatment which gave me plenty of time for what I knew would eventually come... and did. The owner of the Chevelle I'm finishing up right now wanted all the intercooler tubing polished. Fortunately I finally got things pretty well figured out by the time I did the tubing on that one! (pic is end of fab- before everything got polished)

http://i696.photobucket.com/albums/v...psd3013ec9.jpg

Here are some pics from this afternoon. Closing off the cowl vents on the bottom of a 67 Mustang cowl. My helper got a bit overzealous when I told him to clean away the ECoat around the opening but I'm not complaining because his round patch panel was perfect. I didn't even use filler for most of the TIG welding.

http://i696.photobucket.com/albums/v...ps5de7c9d6.jpg

http://i696.photobucket.com/albums/v...psd0a88803.jpg

Now I want to get in and give my .02

its ok to weld ( fusion) with tig without using any filler but you have to understand that by doing that the metal get poor and thats why you can get those little craters and holes. More better material, more it will happen.

Like it doesnt matter much with normal sheet metal but does matter a lot with aluminium ,stainless or titanium.

By using even mig wire now and then when you weld, you can see that it will restore the metal and it will produse cleaner weld. This is something that you have to practice to get good at it.

For purge you can do as has been told here before or you also can use back purge paste witch is also really good thing to have. or if you can, you can also use a ceramic back support, witch you have get out after welding. They are commonly used in industrial cos they are reuseadle and can be used in small area inside large tanks and so on. And they are way cheapper than gaas flow.

It has been sad about cleaness but also it important to weld with correct size and color tungsten and amp level.

If you have a good a machine, you can paly with pulse, so you can set the welding amp, time and weld/rest ratio.

I'll give an exsample:

I made an overflow tank to Atlas Copco diesel power twin screw air compressor from 0.8mm/0.03" stainless and didnt need to purge it at all. I just search the right settings from my machine amps and pulses wice and it welded it nicelly. It did melt them through but pulce upamps stopped just before it get to sugared. Weld it in inch here, another there all way around and it game out nice. Have to get the pictures out of my shop camera.

Definitly agree that the weld is not as strong. When I was playing around with aluminum tubing scraps figuring this out I had some of the welds I had fusion welded fracture when I was "destruction testing" them to see how they strong they were.

Another thing to consider is that when you fusion weld is that the weld sinks in. If you are trying to grind the weld flush after the fact you will have a valley from the weld. Especially when TIG'ing aluminum intercooler tubing that you are going to flush for paint it is better to fill above the level of the material.

Another thing to add to this cool discussion. If you are getting porosity in your weld and everything is clean and the gas is flowing, you may be boiling the weld puddle. If you are welding too slowly you can cause a "boiled" weld puddle.
I typically weld with ER70S-6 filler rod for my mild steel welds. I buy 36" lengths of 1/16" and .045" filler rod. 1/16" is for thicker metals 16 gauge and up to 1/8" thick. I use the .045" for 18 gauge steel. Sometimes when I weld thinner metals I will weld with .035". All ER70S-6. ER70S-6 has more de-oxidizers in it than the ER70S-2. :thumbsup:

:sieg: Guilty!

SuperB70 and GriffithMetal - Thanks for the experienced insight. :thumbsup:

Funny that you mention this as I've just started having this problem.... and interestingly enough I'm welding faster than I used to. Only thing that I've changed is that with steel I've noticed it puddles better when I'm pushing the weld rather than pulling the weld like I do with aluminum so I thought that might have something to do with it.

I'm using 3/16 red stripe (can't remember if that is ceriated or thoriated) tungsten with 1/16 rod as most of what I'm doing is lighter gauge stuff. I did try 1/8" tungsten when I was experienting with the intercooler tubing but with the .065 aluminum tubing I was melting down the tungsten just trying to puddle the weld.

WTF?!?!?!



TIG WELDING IS ALWAYS A PUSH..... MIG you can push or pull.

Greg is right, always push the TIG torch. What's the torch angle? What thickness material are you welding? Thick and thin metals have different welding parameters when TIG welding. Was the 1/8" tungsten green stripe "pure"? You can google the amperage rating for different thickness tungsten and type. Are you welding the aluminum on AC or DC+? Are you using a transformer style TIG or an Inverter style?
I can weld .063" 3003 aluminum with 3/32 red stripe 2% Thoriated without a problem. I use 1/8" green stripe pure tungsten when welding something critical in thin aluminum. I am using a 110amp setting and probably welding at 80 amps or so with a transformer based TIG.
TIG welding is complex at times.

Be nice Greg or your SS exhaust system will crack from welding Karma....

I'll have to try it... probably picked up bad habits teaching myself. Pulling works pretty well for me with the aluminum now that I've got the contamination issue figured out :D

Torch angle around 45*ish. I use Vibrant aluminum tubing to fabricate my intercooler tubing and that is .065. It welds nicely with the 3/32 red stripe and 1/16 rod now that I figured out my contamination problem. My machine is pretty basic...Miller Diversion 165. I'm brain dead right now at 1am but I know the machine is marked which way for aluminum and the other way for steel. I don't remember the details on the 1/8" tungsten right now either... I'll check on my cart I think I bought a pack of them. I know I tried several things on the advice of the welding shop trying to figure out my contamination issue.

well how do you like it? know you have to have at least 1/2 hour on it by now.

Remember to turn your gas down. The first time I ran mine I blew right through it at 15 CFM.