Problem with Contamination in Aluminum Welding

[GMarchand]

Hello, I was wondering if someone could help me figure out the problem I'm having with my TIG. I have a Miller Syncrowave 250 at home, but I also am using one at school, and I am trying to weld Aluminum. At school, when I weld aluminum for practice it comes out really nice, but when I do it at home with my welder there is some brown crap that ends up in the end of every weld I make. Sometimes the brown crap floats in my weld puddle, where it is carried in the puddle until the weld is completed. I told my welding teacher about the problem I'm having, so just to be sure I didn't have contaminated filler rod at home, he gave me some filler rod that we used in class, as well as a few pieces of the Aluminum used in class, and even a small stainless brush in case mine was not stainless. Here are some other facts:

-On both welders I am using the same 2% Thoriated Tungsten
-Both welders use Argon
-Both welders are on the same settings, although I might have the gas pressure setting wrong, I have ranged it between 20 and 35 psi though
-On my torch I put a brand new ceramic and tungsten. I also prepared it with a grinder that hasn't touched steel and I balled the tungsten properly
-My torch is air cooled and the school's torch is water cooled, but I have welded with my torch without this problem before, it just started happening recently.

This problem is driving me nuts, any input would be truly appreciated.

Thanks!
-Gary, GMarchand

[wldrman]

How are you prepping your pieces? Are there any ratty edges left on your pieces? Wiped doen with any cleaners. (acetone, alcohol)

[youngwelder_154]

As usual I havent welding with TIG or Aluminum, But I do read about it, It sounds like you are doing it the way it should be done. But is it possible that your Aluminum is dirty? Or the area you are doing it in your shop could be dirty? I know thoes factors play a BIG role in how the weld turns out. I wouldent think that your torch being air cooled or water cooled would have anything to do with the wierd color you got. You could always try cleaning the torch or just cleaning the Aluminum or even the area you are doing this welding in, its worth a try.

Good luck and keep us updated with what you find out is going wrong

[GMarchand]

Well, I might think that things were dirty too, but it just doesn't make sense that I prepared the peices the exact same way in both instances with the two different welders (I brushed the aluminum with a stainless brush) and in one instance the weld looked perfect and the other one looked like crap. It almost looks like there in a blob of rust floating in the weld pool, that is the closest thing I could relate it to.

My welding table is rusty, but I switched to a clean table and that didn't make a difference. It sure is driving me crazy though... I hope I run into someone who has had a similar problem! Thanks for the replies guys!

[JD in Socal]

...Both welders are on the same settings, although I might have the gas pressure setting wrong, I have ranged it between 20 and 35 psi though...
This problem is driving me nuts, any input would be truly appreciated.

-Gary, GMarchand

Turning the gas up too high can cause turbulence and allow contamination. Don't think that more is better and crank it up, because that could cause or contribute to your problem. 20 is probably fine, but 35 is too much.

JD

[Darmik]

Are the metals the same like 6061, or 5356 some of these you can weld together with no problem what about the filler metal size and thickness is it 5356 or 4043 or 6061 your tungsten try pure the green one gas should be 20 to 25 if you are welding aluminum you should be using that is when I was in school was green ,grey(didn't work very well) and brown I never tried a 2%
(I was wondering stupid question) Do you have your machine set for ACHF
Everything eles sounds fine to me that you are doing.My self im more horney about keeping stainless clean that I am aluminum.
I hope this helps


Darmik

[ryank]

I was wondering on your torch are using a gas lensethat might be your problem>but i would definitly clean every thing with acetone and wire brush

[GMarchand]

Thanks a lot for the input, guys. I'm ruling out the tungsten grade and the cleaning of the Aluminum for now because I am using the same grade tungsten and same preparation methods at school and the welds are coming out perfect. I asked my welding supplier today, and he said it is most likely that my Argon tank has become contaminated. He says this is particularly likely because I had the tank stored for a long time previous to using it, and the tank is at lower than a 1/4 level or gas left. I am bringing the tank to be filled tomorrow, I will let everyone know how this worked. Thanks again for the input.

[GMarchand]

Also, the machine is on AC high frequency, and the aluminum peices and aluminum rod are the exact same peices that I welded with no problems at school. I am using the EXACT settings on the welder that I used at school without any problems. The welding supply guy also told me that I might have to clean the points on my high frquency thing... That'll be the next step if the new tank of Argon doens't cut it

[Darmik]

Thanks a lot for the input, guys. I'm ruling out the tungsten grade and the cleaning of the Aluminum for now because I am using the same grade tungsten and same preparation methods at school and the welds are coming out perfect. I asked my welding supplier today, and he said it is most likely that my Argon tank has become contaminated. He says this is particularly likely because I had the tank stored for a long time previous to using it, and the tank is at lower than a 1/4 level or gas left. I am bringing the tank to be filled tomorrow, I will let everyone know how this worked. Thanks again for the input.

Well that's a new one on me I assumed that the argon was full or at lest 1/2 full anyway but nevertheless I never thought of the argon being empty or near mt tks I'll keep this one in the memory bank.

Tks Darmik

[JonnyTIG]

leaks

It is possible your back cap on your torch is leaking air into torch, or the connection between the collet and torch body.

[GMarchand]

Hey guys, that Argon tank turned out to be the problem. It was contaminated somehow, and that's why the welds came out so bad. I hooked up a new tank, and everything is good as new! Thanks for all your help, I hope this helps someone in the future!

[JonnyTIG]

Contaminated tanks

I've come across this problem before, when working in a large aluminum fab shop. I was told that tanks get recycled and used for different gases over time, by the gas supplier. I don't know if this is true, but it could be why the argon tank was contaminated.