Wow, that 's a great looking welder you got there. Did it take a lot of work?
It wasn't really that hard since most of the connections are already wired straight to the transformer & the plug connections are soldered to each lead. The only moving part is the switch, Which I disassembled & cleaned the contacts with steel wool. Each one of those plug connections will have a lock nut & washer on the back of the front panel, Loosen the lock nuts & then the front caps should twist off. The wires to the plugs are fairly heavy & will stay in place once the front panel is removed, But I put a piece of tape & the amp# on each wire just to be sure! I did clean each solder connection with a wire brush & then applied heat shrink tubing to each connection, Mainly because I all ready had it on hand. Once the panels were all removed it was easy to sand & re-paint them. Then all that was really needed was a wire brush to clean some light rust off of the frame & re-paint the frame. I used a air nozzle to blow out the dust on the coils then wiped them down with some WD-40.
I needed to replace the ground connection plug since the wrong connector had been used & it caused the connection to become sloppy & not fit correctly. I had to use a Miller style connector since the Marquette plugs are a different size & not available any longer.
On mine the top & bottom are metal & the sides are fiberglass, There's a inner frame made of metal that the sides attach to. This frame's bottom is isolated from the main transformer's frame by some special fabric washers. This isolation of the main transformer & the inner frame is important, Since there's a good chance of getting a shock from the metal part of the cabinet after the welder is turned off.
In my case the previous owner had mounted some new casters to the base & he unintentionally (through the bolts used) made the connection between the transformer's isolated frame & the frame for the sides. This caused a good shock if you touched the metal top or bottom right after the welder was turned off! I'm not sure if it was from static electricity or possibly from the capacitor discharging? But “Trust Me” I wouldn't need any more coffee after that jolt! Once I figured out & fixed the isolation problem the welder is user friendly again, No shocks at all & it works great!
Doug