Common Problems encountered with TIG - Part 3
“I’ve got the correct polarity, using the correct type of tungsten, have checked for correct balance, and even checked for drafts around my TIG work area, but I’m still having problems with my tungsten burning up and contamination in the weld. What’s wrong with my machine?” If a customer is saying this to me, it sounds as if he is on the ball with his diagnosis attempts, and is trying to do his/her due diligence when isolating the problem. At this point it does become a matter of tedious elimination. If gas flow can be confirmed from the welder, it isn’t the welder itself…and the cause must be found elsewhere. There are a number of minor, but still relatively common causes that must be evaluated as the possible cause of this condition. One is the possibility of contaminated gas. This is fairly common. Usually argon is contaminated with CO2 or air due to lax purging techniques at the gas distributor. This can cause variable results with periods of the weld going smoothly and then nothing going right. This intermittent or constant irregularity in welding can only be rectified by swapping cylinders. But bad or contaminated gas usually happens in batches, so it may take exchanging gas more than once to eliminate it as a cause. As frustrating as this can be, gas supply companies offer little cause or reasoning. Metal contamination by coatings can be a cause of this, particularly galvanized metals. This will cause a significant amount of flaring and gas and is usually easy to see. But when welding aluminum, you can often see specks of pepper like substance in the weld or with DC a dull appearance may result after the weld is completed.