On my '67 between the back window I was looking at the panel. Where it meets the roof sails, there is a seam. There is no rust (thank God). Someone once told me they filled in the seam with bondo to prevent it from rusting. Is this a good idea or not really?

hey bud as u may have seen in other topics im not a big fan of bondo, but i still would not fill that area with it anyway just keep it clean and out of the weather and it should be fine!!!! graemlins/thumbsup.gif

As far as keeping it out of the weather...That's not possible. I have no garage or shelter.

DO NOT FILL IT WITH BONDO!!!
Bondo traps in moisture... if you are set on filling this area use something with sealing capabilities.

you can't fill any seams with filler and expect them to hold up. Prime the area with a good metal primer and use seam sealer to bridge and seal the void. The metal pieces expand and contract opening and closing this joint slightly so you need the flexible sealer to seal this up. If you want the smooth seamless look you'll have to weld it solid or use body solder.