Welding Tips and Tricks

I continue to have issues with porosity in my welds in steel. I finally realize that there is one fundamental difference between welding with a oxy torch and welding with TIG and that is that I have complete control over the direction of the torch flame, but sometimes with TIG the arc wanders from one piece to the other. In some of Jody's videos and writings he mentions that too low of an amperage with too large an electrode can cause an unstable arc. Are there other things that can cause an unstable arc besides wind? I'm being careful to avoid air currents and I'm following published guides on Argon flow. Typically I'm welding 1/8" mild steel with a 3/32" electrode (2% lanthanated sharpened maybe 45 degrees with a flat on the end),#6 cup, about 7L/MN(it's an everlast flow meter), at about 125A, using 3/32" es70s6 rod. As I write the above, I am reminded how many variables there are to TIG welding. I'm cleaning the joints well. Sometimes I get good results, sometimes not. Could I be moving too fast so that the previous area hasn't solidified enough? There I go thinking out loud again. I'll try to post a picture if you think that will help.
Thanks,
Joe

sounds like you might have a bad ground....

tigmaster wrote:sounds like you might have a bad ground....

That was my first thought also but after the weld has been started there shouldn't be any difference in the ground between the pieces. I'm more inclined to think that the tungsten grind is the problem. The tungsten shoud be ground to look similar to a freshly sharpened pencil. Make sure you use a dedicated grinding wheel that has never been used for anything else and never dressed with a wheel dresser.

With a Lanth tungsten on steel just grind it to a point, don't flatten the tip.

whats the problem with using a non dedicated grinder? i ground a lot of steel with the same one that i used to sharpen my tungsten.
is it just that filings with a low melting point get on your electrode?

The times I've had arc wander were when I wasn't running enough current for the tungsten size, or when I had contaminated shielding gas.

I would go with a 1/16" tungsten, which should be good for 150 amps on DC (according to this oh-so-handy CK Worldwide TIG welding specifications document): http://www.ckworldwide.com/tech-3.pdf

I'd go with the standard end prep, which consist of grinding the tip to a fairly sharp point (like a pencil, as steve stated), and then grinding a small flat on the very tip. (to increase the current capacity of the tungsten before the tip melts.)

If you don't have 1/16" tungsten, then grind your 3/32" tungsten to a very long, slender, tapered, sharp tip (no flat on the end) to help its tip get hotter at lower currents. This will help with arc starting and stabilize the arc.

If that doesn't fix it, you sure you have good shielding gas? And a clean workpiece?

You also might try some high frequency pulsing if your machine has it; which helps "stiffen" the arc and make it more directional. However you probably shouldn't need to resort to that to solve this problem.

if all Jakeru said is not working , then you must keep the tungsten closer to the weldpool, i bet this is the problem.

mild steel will spark and bbl just like cast iron if you use too much amps or weld speed is too low.

Thanks for all the tips, guys. I am doing better after reshaping the tungstens to a finer point and making sure I keep the arc close. I also rechecked my ground.
I'm getting a higher percentage of good looking welds. I think now I need a lot of seat time to practice.
I realize one problem is my impatience. I'm sometimes moving too fast. I've got to concentrate on the pool.
Joe

I'll throw another one at you.. Cheap tungstens... Try buying a good U.S. made Sylvania. I'm not that good at TIG yet and I was having a hell of a time on edge welds. I was saving the Sylvania's for a real job and practicing with the Radnor ones. I put a Sylvania in the torch and suddenly I was sticking edge welds like I was using a glue gun. I finally saw the elusive keyhole on a butt weld and got full penetration without making a friggin mess. Yes, I'm still talking about welding..LOL..

i'm pretty happy right now knowing that I'm not as slow at learning this crap as I thought I was.

Steve,
Can you tell me where to buy Sylvania tungstens? I have some tungstens from Diamond Ground that should be good and seem to work well. I was able to buy those after someone posted a seller on ebay. A couple of welding supply places on the internet couldn't tell me what brand I would get if I ordered from them ??? which didn't make much sense when I keep reading in books that the quality of the tungstens is really important.
Joe

Joe wrote:Steve,
Can you tell me where to buy Sylvania tungstens? I have some tungstens from Diamond Ground that should be good and seem to work well. I was able to buy those after someone posted a seller on ebay. A couple of welding supply places on the internet couldn't tell me what brand I would get if I ordered from them ??? which didn't make much sense when I keep reading in books that the quality of the tungstens is really important.
Joe

http://www.arc-zone.com has them. Be prepared for a little sticker shock.

Here's the deal. I put a 3/32 1.5% Lanthanated Sylvania in the torch today and went through a pound of 3/32 5056 rod while welding 3/16 6061-T6 at 150 amps with pure Argon. In order to make that work you have to use a lot of negative voltage and stay really close to your work. Normally, that will fry a tungsten in a very short period of time but the Sylvania's held the point way beyond my expectations. I used the same tungsten all day long and only stopped to sharpen it three times when I noticed it start to wander a bit.
I'm a believer and you can't go wrong with Arc-Zone either. When's the last time you had someone call you after an internet sale to make sure you were 100% satisfied? Arc-Zone did and not just the first time I ordered either. Great company to deal with.

Thanks, Steve. I'll try Arc-zone. I need some 1/16" electrodes anyway.
Joe