Welding in Patch Panels on a Cowl

[Terry, NJ]

Kevin, You're one of the last people on here I want to debate with over anything, But I want to point out that heliarc is merely TIG with a different gas. The equipment is the same (Cups, handle, Tungsten electrode,variable power through either a footswitch or thumbswitch) but most welders use the 25% argon, 75% CO2 mix for costs. We used the gas interchangeably for aluminum and steel. The only the we changed was the polarity, AC with high freq. start for aluminum, IIRC. It's been a while. I agree with you on every other point.
Terry

Originally Posted by Kevin in NJ

I probably should not correct some things people have wrote, but I will.
I am not trying to be mean or cruel.

Hammer welding is what a blacksmith does. You get the metal hot and hammer it together. What I talked about is not hammer welding. It is using the science of metal that it shrinks with every weld and you have to correct it.

TIG welding is not heliarc. You use helium when welding aluminum. Some aluminum has to be welded where there is little oxygen or other gases.

Most people have MIG and that is what they have to learn to do their best. MIG is a PIA for doing good shrink correction. You need to grind both sides very flat so the hammer process does not cause more distortion locally from the 'blob'. Been there done that a lot.

Having been fortunate to have a TIG welder I can say that is the absolute best for doing wonderful sheet metal work. The heat control allows for laying in just enough heat to get full weld penetration while using little or no filler. Couple that with hammer corrections for shrinkage and even a bad welder can make panels come together and leave the metal close to the original contour.
Another advantage to TIG is the heat control makes it such you can run welds right up to the edge and not have the nasty burn back. The first time I did that I was in heaven.

Another method that works is oxy/act welding with a very small tip and low pressures. You also need to use the correct welding rod for best results. TIG rod (or MIG wire -er70-s6) is not the right stuff! As with TIG you do lots of spot welds and frequent hammering to correct shrinkage.

There are various metal fabrication websites with lots of info and you can rent videos from smartflix if you want to learn more.