I have done a fair amount of body riveting. I have found that you really need a 3X or maybe even a 4X rivet gun, not an air hammer to set the body rivets cold. A cheap Harbor Freight air hammer will work, kind of, but the long throw 3X works much better. Since my wife wont help me much anymore on the car, I have found ways to set body rivets by myself. I am attaching a couple of pictures of a setup I made to rivet floor pans and other 3/16" rivets. It consists of 1" solid steel rod pieces and 1" pieces of pipe and couplings. With short pieces of rod and pipe, I can adjust the length to provide a buck for different areas (heights). I use a hydraulic press plate to prevent chipping the concrete floor. I have more pictures of my riveting stuff if you want to see them. Send me an PM with your email address. BTW, you can usually pickup used 3X rivet guns for a good price on eBay, that is what I did.
Rusty Nelson
