I have an application where I have a 3/8" thick plate, mild carbon steel. One side is painted with an industrial enamel rated around 250 deg F, the other is unpainted. On the unpainted side I am performing some stitch welds running about 200A. Using 1/8 Tungsten, and 3/32 filler. The bead size is between 1/8-3/8" and about 2" long. I am having trouble because the paint on the opposite side is bubbling and distorting from the heat, causing unneeded rework of the paint. I need a method to capture the heat and prevent the paint on the other side from getting ruined. The opposing side must be painted before welding due to our process and limited painting requirements post weld.
Thanks so much for any and all advice.
Do you have the capabilities of GMAW "MIG" process? Even though TIG is better for low heat input applications, running at 200A you should reconsider. TIG is slower process where you are spending to much time in a small area with your amperage. If TIG is your only option then I would try a two pass step, where you are putting in a smaller weld and letting in cool until you can put in your final pass. course I would change the painting process also
Marcuss,
I would turn your amperage down to about 150 Amps and use a 1/8” wire. Less heat input and you can carry more metal with the 1/8” wire and move faster. That might do the trick. It's all about heat input and travel speed.
thanks
Jim
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