I just stripped one side of my truck. In doing this there is a few spots that are gray. They seem thick,,but are soft due to the chemical stripping I have done. My question,,how to tell if its bondo,,or primer. I see no big or small dents in these area's, front or back of the panel. Any answer's would be nice. ThANKS
Uncle Red
Favorite Answer
First go to the auto parts store and get a can of Bondo (just in case) then take a sharp instrument and apply a little pressure not enough to scratch the metal but enough to see if it gouges the bondo. Believe it or not 99% of cars have a slight patching done at the factory for smoothness. I see a lot of cars at the body shop stripped down and have bondo. If it is no problem as you can patch it easily if it gouges. you say you see no dents. they may be very slight.
Wash off the chemical strip and let it dry thouroughly before testing....
cdever5
Most (if not all) auto manufacturers use bondo in the manufacturing process, before painting. It would not be unusual to have factory bondo filler under the paint. Use a magnet (there are special ones you can buy that will tell you how thick the plastic filler is) and unless there's rust under the filler I wouldn't worry about it too much.
Anonymous
Usually If it is primer someone had put a piece of sheet metal under it and welded it.. If it is bondo you will sand it down and find a pink like place.
cgriffin1972
Drill bit will tell all
Go slow with a sharp bit - if it's metal no biggie
If it is bondo it will drill right to the metal or lack there of
Anonymous
Go over it with a hammer. Bondo will crack or fall out.