I needed a more portable arc welder so I built this unit 110 V unit that weighs 40 lbs. It is made entirely of scrap parts. The frame is wood, the welding and power cables are from appliances, and the transformers/wiring are from microwaves ovens.
It is made form 3./4" plywood scraps. It uses a piece of EMT tubing as a handle. It is easy to pick up with one hand to tote around. I can not say the same for my other welder.
The unit has infinite welding current control and can do around 60 amps max. It uses a massive light dimmer type circuit to control the welding current. The circuit controls a triac which varies the input power to the transformers.
The transformer primaries are put in parallel so both are energized with 110 volt. If welding too long at max power it will pop the breaker on a 20 amp circuit. Running slightly lower output works great. The transformer secondaries have been cut off and rewound with 12 gauge copper wire, and then put in series to generate approximately 50 volts AC. This then goes to the bridge rectifier.
The bridge rectifier is rated at 60 amps and converts the AC to DC, multiplying it up to 75 VDC open circuit, which goes to the filter choke. Another microwave transformer core that was completely rewound with 12 gauge wire (50 turns) serves as the choke to smooth the welding current before it goes to the electrode.
The ground clamp is a battery charging alligator clip. The rod holder or "stinger" is a standard model that cost $10. The ground and electrode welding cables are made from 3-conductor, 12-gauge appliance cables with the conductors in parallel to give 60 amps + capability and minimize voltage drop. Also this makes the cables very flexible.
I was able to weld with 1/8" rod without trouble, you can see my first test bead above. Both 1/16" and 3/32 rods also would work. Due to the high OCV of the welder, I am able to start the arc very easily.