I was working on my 71 K20 - build thread
here getting the back of the cab ready for paint and when I got up toward the top of the roof to address the 2 holes that were in the roof from P.O. that had a C.B. antenna mount I noticed some pitting. As I began to sand the area I could see a few really small pin holes. So I proceeded to push down on a few and they were paper thin and broke through the surface of the metal. I then took my die grinder with a burr bit on the end and drilled through to ready them for repair.
Then I got to thinking about the best way to repair this area so that there will not be an issue down the road in years to come. I thought about just welding up all of the holes, then thought about a complete replacement of the roof. After researching the forum threads on this topic and watching a few videos here is what I have come up with for a solution the repair.
- cut out the area that is outlined in red
- use that piece for a template for new metal
- if there is crown in the metal because of the shape of roof, do a little shaping on planishing hammer if needed
- with the metal cut out treat the metal inner roof and upper inner metal with Ospho 605 metal treatment to convert any existing metal from rust to iron oxide
- after that has done its job then treat all of the metal inside the roof with 3M Cavity Wax Plus 08852 and use the medium applicator wand that sprays the wax in a 360 degree fashion to coat everything for future protection
I have never had to make repairs on top of the roof in all the trucks I have built over the years. Any suggestions would be great and welcomed.