To the OP: until reading this thread, I would have agreed with you 100% and assumed you'd win this bet. And it looks like 4ocious does too. But I'm shocked to see how many people say it should be fine to leave the body in a metal state for a long period of time (assuming it's treated properly).
This thread is very pertinent to me right now. I have my 68 FB fully disassembled. My desire would be to media blast the car, bring it home in bare metal and continue to work it with my boys. Things like raptor liner or POR15 for the interior. Painting the engine compartment and outer aprons. Frankly, I don't have $15-20k to drop it off at a painter and have them do it all.
In reading this post, it seems like I could blast it, bring it home and continue working on the car. And at some point, it'll be ready to take it in for paint. I live in southern Cal where it's pretty warm and dry. You guys think I could proceed in this way?
- POR 15 is for painting over rust you can't remove or don't want to remove. Nothing wrong with POR 15, but if you're media blasting your car, POR 15 isn't the right choice.
- Likely, you'd be fine in SoCal leaving the car in bare metal. Optimally I would suggest you bring the car home and spend a lot of time cleaning out the blasting media. It gets everywhere to include inside the rockers. Use a good shop vac to suck all that stuff up. Shoot compressed air into the rockers, frame rails and torque boxes. Again, you'll get a lot of media coming out. Keep doing this again and again until no more blasting media comes out.
- Once you've got all the blasting media cleaned out, spend more time wiping everything down with wax and grease remover.
- When the body shell is clean, clean, clean, shoot on two coats of epoxy primer. There are many good epoxy primers. I like SPI. (Use whatever wax and grease remover the manufacturer recommends.)
- With two coats of epoxy, your car will be fine while you do the body work. Scuff the epoxy and put the filler right over it. You can push the car outside and, if it gets dew or little rain on it, no big deal.
- I would not recommend using Raptor or any similar product on your Mustang. It's your car and you can do what you like, but I think bed liner on the bottom of the Mustang looks kinda lousy. Furthermore, if you ever sell the car, potential buyers will wonder what you're hiding under that bed liner. I would suggest you apply seam sealer over your initial two coats of epoxy then apply two more coats of epoxy. That will seal the bottom very well. You can top coat with something like chassis paint if you like, but it's not necessary for the bottom of a car.
- For the interior, consider something like Lizard Skin if you want a spray-on sound deadener. That will work much better than Raptor.
FYI, I built a rotisserie out of construction lumber when I had my Mustang as a bare shell. It allowed me to clean out all the blasting media, shoot on the epoxy and apply seam sealer to the bottom. It's in my build thread if you're interested.
Have fun!