Help! TIG ALUM welds now suck!

By drjclark Date 10-04-2003 03:50

I changed tanks today and the welds appear contaminated. I did not get the gas from my ususal source. Nothing else changed! Also noticed that the pressure regulator gauge needle fluctiates during welding. Took the tank back and exchanged it, but same problem with second tank. I asked the guy if he was sure the tanks were PURE Argon and not mixed. He said it was pure and is labelled so on the tank.

Could that run of tanks (he said these were new) be contaminated?

Any ideas? Remeber, nothing changed from my setup piror and everythjing was cool.

THanks, for any and all help!
Coop

By brande

Date 10-04-2003 06:08

While this is a bit late in the year, contaminated argon can happen at any time.
Argon is most easily contaminated with moisture. This is easy to diagnose. Moisture contamimination often leaves a tan to brown covering in the weld area.

Weld problems are not as hard to figure out as many would like you to believe.

Example-You were welding good until you switched gas bottles. My first guess would be to check the gas supply.

Don't automatically accuse your gas supplier (although they are more often at fault than not).

Check your hoses, connections and the like. A crack or hole in the gas line can often give the same results as contaminated gas!!

A fluctuating pointer may indicate regulator problems-be sure to open inert gas cylinders as far as possible-to maximize flow.

Hope This Helps

Good Luck

brande

By drjclark Date 10-04-2003 13:31

The electrode starts to blacken as if the gas flow has stopped although it has not. And the welds appear "grainy" and have black specks. Then as I run a bead the discoloration you mentioned occurs. The filler rods tend to curl up and back away from the weld puddle (no wetting action), and the usual wet shiny appearance of the bead now gets crusty and appears to have a film over it.

I will check everything else that you mentioned as well.

Thanks for your help!

By Ken Dougherty (**)

Date 10-05-2003 00:12

Had the same problem in class a few months back. Changed bottles and all was well.

Have noticed a gauge needle fluctuation, like you described, at home once. It self corrected. Have no idea why.

Ken