Microwave Oven Transformer Welder.

There's already a great instructable for how to build this here

But I thought I'd post some pictures of what my friend and I came up with as our finished product, and just show off a little.

The picture quality is likely on the "eh" side, I'll get some new ones with a camera that isn't my cellphone soon. It works though. That silver dot in the last picture is a hole I filled in a bar of 1/4" steel with some 1/16" 6013 welding rod I picked up at Harbor Freight for 5 bucks. It welds pretty nice actually.