I completely stripped my 55 down to a body and a frame. all pieces and parts were dustless blasted. Best thing that I ever did for the car. afterwards I sprayed the car down with Ospho to keep the rust off the metal. This way I can work on the car as long as I want to before priming. The trunk trailing edge ended up having pinhole rust underneath the bottom edge. Instead of cutting this out I put duct tape over the holes and then mixed enough marine epoxy to pour into that space from inside the trunk lid. After it set up I removed the duct tape and sanded the outside area. Then some minor body puty and sanding restored the area. The epoxy effectively sealed the rusted area as the Ospho had killed the rust. By not cutting out the area I eliminated the warpage from cutting and welding and retained the original body lines and decreased my down time. This also strengthened the affected area and cannot be detected with a magnet. I may have misspelled Ospho. It is an acid that changes iron oxide (rust) into Iron Manganese and primer sticks to it with no problem. I have no problem with painting when using this product. I use it on all steel parts.
I did have a problem getting the sanding media off the car as it did stick everywhere but when the car is disasembled a pressure washer works wonders. after pressure washing you let the car dry and spray it down with Ospho. just my 2 cents worth.