Spot Weld Removal

Started removing the qtr panels on my Dart. I have a decent weld cutter, but the main problem: I can't visually find all the welds. I took my body sander, and removed most of the paint, hoping the welds would be left visible. I could see a few of them but rest were not visable. The metal was not even indented to where I could feel a weld. Any tricks of the trade that might be of some help. Tnxs: Howard