Kevin explains that a closed vessel is an enclosed container. When you are welding that container together, you usually have one end to weld on last. To finish it, you have to get to that last little spot. And now you have a closed vessel.
Why is that a bad thing? Because, as you’re welding, you are heating the air inside the vessel. If it gets too hot, the inside air is going to want to blow out. Now you have a bigger hole to fill.
What do you do about it? Kevin uses 1 of 2 ways. He shows the joint he is welding, which is his last joint. He doesn’t want to have a blowout.
Another method is to find a spot out of the way and away from wherever you’re welding. Drill a small hole (1/8″, 1/16″), just enough to let it breathe. Letting the air escape reduces the pressure building up inside as you’re welding.
Finish your weld, then come back to that hole. Dab it with your welder, and you’re all done.
It’s time to make sparks! Kevin uses a foot pedal to control the TIG weld. When he gets close to the end of the weld, he backs off the heat a little and backs off the amps. The weld cools down a little, letting the residual heat carry it over to weld the vessel shut.
Kevin shows the weld that closed the vessel.
Kevin hopes this information helps, and appreciates you watching. If you enjoy these free how to videos, please hit that “like” button.
Before you head out, hang around for another moment to see him underestimate his own strength ….