This web site has been a great resource for me being a DIY welder so Here is my Mig welder I built because I felt it would be a fun project. and I feel you will become a better user of a product after you know how it works. The gun is a 600amp Tweco gun I got of eBay for $24 The Feeder is a Lincoln LN-9 Wire feeder ( or so I was told) bought it for scrap on eBay for $20 Here are the specs on it Feeds up to 3/32" ( 2.4mm ) solid and .120" ( 3.0mm ) flux-cored wires, from 50 - 600 inches per minute ( 1.27 - 12.7m/min ) wire feed speed. Had to make a variable speed 90VDC motor driver for it. But works great. Also made the spool holder for 10lbs spools but have a small one on it now to test. The feeder was junk when I got it. after some TLC and a little home brew refurbishment i think it looks good as new, The bungee is my tension system for now haha. Oh and I have in it 0.035 flux wire now. ( I have a regulator just need to make a bushing to alow the gas to enter the gun socket. The transformer is from an industrial UPS system it is 1’square and about 80lbs and can produce almost 500amp at 40VAC Right now it is running at 50amp 220V and is about 200amp output DC or AC. The Diodes I got of Ebay for $10 They are 600amp. Stud mount about 1" stud. I made my own bridge plates from 1/4" The unit even after 30 min of welding remains just luke warm.