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randyjaco
01-17-2009, 08:34 PM
Hi All,

I haven't done any Aluminum welding in about a year and I am having problems. I was modifying a aluminum tube that I welded up last year. It welded up pretty good then. Well today today it just refused to lay a bead.

I have an old Heliarc 250HF that does a great job on steel and did an adequate job on aluminum once. So today I put the dial on AC, turned the High Frequency to 100%. I grabbed a new 1/8" pure tungsten electrode and sharpened it up. I then cleaned the aluminum with a stainless wire brush and then cleaned the aluminum, the electrode, and the filler rod with acetone. I got everything on place and attempted to tack the pieces together. Well all I got was an arc with a lot of popping. The popping just increased in frequencyas I stepped on the foot pedal. I had to lay about 3" of bead and I used up about half an electrode. I would have difficulty calling what I ledt a bead. Any thoughts on what I am doing wrong.

davidh
01-17-2009, 09:18 PM
what are yoou using for gas ? ? ? ? have you got a bad tank, ? i've seen that.

randyjaco
01-17-2009, 11:31 PM
I am using pure Argon. The tank is starting to get low, but it still flows well at 30 cfm.

PatTheRat
01-18-2009, 12:14 AM
Sounds like a cold metal problem.

Is the work cold? Did you preheat it?

My first post here and I think this is an awesome forum. I think my crowning achievment for last year was getting my old white faced Millermatic 35s to weld aluminum with a spoolgun. Everyone said it couldn't be done.

Just bought a Logan mdl 920 11x28, and am learning machine work. I'm setting up a home all solar powered machine shop. Looking to get a Bridgeport vertical mill, and convert it to DC drive.

Berniep
01-20-2009, 01:03 PM
I am using pure Argon. The tank is starting to get low, but it still flows well at 30 cfm.
That sounds like a very high flow rate. It can cause turbulence and draw in air which is what your problem sounds like.
Most recommendations that I see say just under 20 unless you are doing something special.

randyjaco
01-20-2009, 10:40 PM
The aluminum was @ 70 degrees F. I never heard of preheating Aluminum for TIG.

You might have something there with the flow. 30 cfm was what we used in my welding class, but it does seem like a lot on my system.

Phil McCrackin
01-21-2009, 07:35 PM
Using up half an electrode kinda sounds like the cleaning action is way off. Too much current going into the electrode and melting it away.

Some other thoughts;

What thickness and Al series were you welding? Although this can't be your problem, I generally use 3/32 for everything up to about 1/4 inch, so 1/8 seems a little overkill. Also was it 7000 series Al? I have 'heard' that 7xxx series Al is damn near impossible to weld by hand.

As previously stated, I keep my flow to 10-20 cfm.

Are all of your grounds good? i.e. work to table, table to clamp, clamp to machine.....

Lastly, I just had this happen to me. There was some "stuff" on the back-side of the pieces I was welding and once I got to that part of the work, the fumes given off contaminated the weld pool and totally destroyed my nice bead. :( I had cleaned the hell out of the top and freshly ground the electrode... but just forgot about the backside.

doctor demo
01-22-2009, 02:51 AM
Hi All,



I grabbed a new 1/8" pure tungsten electrode and sharpened it up. I had to lay about 3" of bead and I used up about half an electrode. I would have difficulty calling what I ledt a bead. Any thoughts on what I am doing wrong.
Well every time I weld Al. I sharpen the electrode and then I ''ball'' the tip. You did not mention if You did that, but if You didn't You may have been blowing molten tungston into your weld pudle, that would cause some trouble.
That along with the high gas flow rates.

Steve

shoprat
01-22-2009, 12:14 PM
i am not sure on your machine,but do you have the polarity right. and also you dont have to intentionally ball the tung. it does it automaticly when you start welding. hope this helps and let us know what you find out.

randyjaco
01-23-2009, 07:49 PM
I found the problem. I had the high frequency switch set at Start rather than Continuous. I now have a yellow "Al" sticker next to the Continuous position. Maybe that will help me remember. I also need to remember to flip it back to Start.

Thanks for the suggestions. I should at least have a Argon bottle last twice as long:D
I also improved my grounding, just in case.

Randy