I have put together a slide set for those who may not have used a welder to remove broken bolts, I have removed well over 30 bolts from my 1950 3600 in the last couple months using these steps. The photo's are on page 5 of this link.
http://community.webshots.com/user/RugerWSM?vhost=community Step 1: Photo BB1-this is all the tools required plus a welder, just a simple buzz box or a Mig will work as well.
http://good-times.webshots.com/photo/2587719320102454676dZrLat The bolts were 5/16" and these were both sides of the front fender under support pieces.
Step 2: Photo BB2-wire brush the area, I turn them over and pull on the side where there is some bolt sticking out if possible. It will work even if they are broken flush with the piece. Just make sure you weld the washer to the bolt.
http://good-times.webshots.com/photo/2535906110102454676BbvTJcStep 3: Photo BB3-Place washer over the broken bolt, (I use a heavy washer where possible) weld the washer to the bolt, chip the slag and brush. I use Brutus-A 3/32” stick electrodes because I have a supply of them (about 80 amps on the setting). 7018 will work as will alloys like 308, 309, 347 or similar. I would not use deep penetrating rods like 6011 or 6010 since they will usually break when you try and remove them and could damage the piece you are working on.
http://good-times.webshots.com/photo/2265370840102454676COsGFUStep 4: Photo BB4-In this case I used 5/16” nuts since they were sized to the broken bolts but you can use smaller or larger depending on the ability to get a couple tacks on opposite sides of the nut to the washer. I only weld on two sides so that when I use the adjustable wrench there are unblemished surfaces to get a grip on. The bolt is for you to hold on to so you don’t burn your fingers.
http://good-times.webshots.com/photo/2163730550102454676kgrlnnStep 5: Photo’s BB5 thru BB7-This shows the steps for removing the bolts. I use a small wrench and work it back and forth slowly as soon as the nut has gone off cherry red. This puts all the heat right in the broken bolt itself . If it should break off just repeat the steps, rarely do I have to do this more than twice per bolt.
http://good-times.webshots.com/photo/2705059670102454676rvJFrGhttp://good-times.webshots.com/photo/2901280040102454676FodwGIhttp://good-times.webshots.com/photo/2396801810102454676MDVpDMStep 6: Photo BB8-Both bolts are out and now you just clean up and run a tap through the holes. I have used this technique to remove bolts as small as 10-32 with 3/32” electrodes. It does not take a lot of weld as you can see, to remove these bolts took only about ½ of one electrode. I removed four bolts from both sides in about 15 minutes using these steps. It will also work in position on the truck but it is best to practice flat until you get a feel for it.
http://good-times.webshots.com/photo/2742810590102454676BUtagA