I started out with actual welding machines. The 2 stick welders I have are heavily modded.
But then I power factor corrected them, added DC, installed inductors, convenience receptacles, ducted their fans, ducted the air flow so fresh air gets drawn in and hot air gets blown out (air was just getting mixed around inside of the housing by the fan).
The little stick welder can now be used for TIG.
All the DC components I added can take a beating. With the large welder I can set it on 230 amps take a 3/16'' 18 inch long 7024 electrode, burn it all the way down to the wire, drop the stub and burn 2 more with out the machine over heating.
My mig welder just has a gas purge switch, I clipped the capacitor bleed down resistors on the main board and replaced them with a "train fan", a 28v DC fan on top of the machine. A tiny version of what you see on a diesel locomotive. Has a DC volt meter showing volts at the leads, I added an additional 100,000uf capacitor to the output side and gave it power factor correction.
I talked about them a little bit here:
Eco mod my welder - EcoRenovator
Fan control so I can run the fan with the transformer off or not run the fan at all when welding on the lowest settings.
Arc softening capacitors boost voltage if needed for some applications.
DC side receptacles with and without inductance. Pulsed DC is a wonderful thing with some electrodes.
Input volt meter.
