I have a 52 3100 and I patched my frame with some 1/4 inch stock ,I built the patch 21 inchs long to get rid of the rusted area I left the top of the frame alone than I reinforced the top buy weilding a pc, of 2 inch +2inch angle iron to the top and made sure the frame was supported than I marked the area using the patch I made so it would be a perfect fit , cut out the bad area and beveled the edges to get a good weild than ground down to make it look good and done, got to take Your time , My frame was rusted out where the rear springs mount on the front spring bolt on both sides . After I was all done I removed the angle iron on top with My grinder and that was it , have fun!!!!!
Pete
