Could someone have a look at these beads and tell me why do I get the bubbling? Someone previously told me it was because the metal was dirty but this piece is clean. I even used some thinner on it to clean it.
Sorry for the question but I live in Taiwan and I can't really take a welding class. Thanks, Raul
it's definitely a form of contamination, if this happens when you don't use filler, then be sure, your tungsten is sharp, you have good gas coverage, no leaks in the line, what is the base metal?
Write back and let us know; what tungsten your using (2%?) what shielding gas what is the base metal
Ok, here's the story. I needed some welding done and was not having much luck getting exactly what I wanted. (My Chinese is not that great.) Welding machines are cheap here so for $300. I bought a TIG machine.
I've been practicing in my spare time.
The tungsten is red, you can only really buy red ones. The other colors are not readily available (I don't know why).
The gas is argon with a #5 nozzle.
I don't think there are any leaks in the line.
I don't know the metal, there are shops everywhere that just sell it by the kilo so I just pick something out and they weigh it. For one buck I've got 2 kilo's of metal. They say it's steel.
I welded some stainless steel piping (see photo, like for towel hangers) and got the same bubbles.
The filler rod is steel. What kind, I don't know.
I realize that steel is a big catagory but Chinese is not really a specific language. Galvanised steel is known as "outdoor metal". "Smart" and "clever" are actually the same word in Chinese. It's hard to know what grade of steel it is, (I doubt they would know anyway to tell the truth...).
Any help you can give would be great.
Thanks, Raul
The appearance of the stainless steel tube weld is better than the steel, but it also has porosity and is excessively oxidized (dark black and crusty rather than shiny metal) thus indicating poor shielding gas coverage.
Ensure you have no gas leaks. Plug off the gas cup with your finger, turn on the gas and use a soapy water solution to check every gas fitting for bubbles indicating a leak. A pressurized gas system with a leak can actually draw in air and contaminate your gas.
Experiment with your gas flow rate, too high can cause turbulence and actually mix surrounding air into your Argon shielding. Only 5 to 15 cubic feet per hour (cfh) may be needed.
Use a gas lens.
Minimize the distance that the tungsten electrode protrudes out beyond the end of the gas cup.
Minimize the arc gap, the distance from the end of the tungsten electrode to the work piece. The closer the better, as long as the tungsten does not touch the weld, 0.030 to 0.090 inch.
by the look of the brown smoke in the top pic. your tungsten is contaminated with steel (filler or parent metal) lines 2 and 3 don't look too bad so the porosity is probably not coming from the torch as much as your technique or the steel Dave .
Well, I tried on the face that had been cut and had no problem. It must be dirty metal.
Assuming it's stuff that has been sitting around a shop for a while, how should I clean it? Just grinding the surface didn't change the bubbling problem.
Raul
Hello
You can run into problems with porosity if the filler metal you have lacks deoxidizers, check with your supplier to make sure they have supplied you with the correct filler metal.
I'm only a newby TIGer, but the 2nd bead from the top looks pretty good except for the "fish eye" at the end. That only means you pulled too quick without sliding back on current. I would think that if you could get that 2nd bead once, you can do it again with the same material. Seems to be a practice issue more than dirt.
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