~ 1969 undercoating inside of doors

[Raven R code 281]

On the inside of the doors....the original door skins have a heavy coating of undercoating. Question....what is the best way to apply to doors that are already painted?

Also....what is the best method to coat the lower corners of the doors to prevent any future corrosion?

[RPM 1,190]

After the doors were painted I sprayed the insides with rattle can bed liner and used a dynamat knock off on the door panel. To prevent the undercoating to pass thru the holes in the door frame, I covered then with masking tape.

 

 

[Brian Conway 264]

The undercoating on the inside of the door skins was more for noise suppression than for preventing rust.  Keeping the lower door weep holes clear will go a long way in rust prevention.  Brian

[69RavenConv 286]

I used rattle can rubberized undercoating. As pointed out above, keep the drain holes clear.

[Bob & Sue 110]

I just finished replacing the door panels first I sprayed on a rust inhibitor let it dry then installed this insulation it sticks is easy to get in the small openings and a lot cheaper than most other products. It comes in other sizes depending on where you use it, I also covered the new black trunk mat liner (repop) & under rear seat insulation with this stuff. Will use it when I replace the carpet also can't see paying the price of other brands.

http://www.homedepot.com/p/E-O-12-in-x-15-ft-Self-Stick-Foam-Foil-Duct-Insulation-FV516/100028603.

 

[Raven R code 281]

To clarify.....the undercoating is strictly sound deadening on the inside of the door skins. For the very bottom of the doors, I would like to saturate with some sort of paint/ coating to protect the lower corners from the typical garbage/corrosion issues.

[Mach1 Driver 560]

You are talking about inside the door where it is difficult to get to, and its inconvenient to sand blast- correct?

I keep I file on this kind of stuff. I haven't tried any of it yet, but this is what I've read, and it all variations on a theme:

1. Machinstmate.com/rust-freeze/. Remove loose rust first. Apply one thin coat, takes two weeks to cure in 80-90* weather. Will creep down into seams and overlaps.

2. KBS-coatings.com. 3 step process (1) cleaner degreaser KBS Klean, (2) Rust Blast removes rust and etches, (3) Rust Seal, then put on a top coat.

3. Wire brush the rust spots. Apply Navel jelly- which is in fact phosphoric acid. Let it sit for 20-30 minutes then clean it off with Windex, rubbing alcohol or water. Once dry brush on KBS Rust seal. 

4. Some people suggest buying regular phosphoric acid at a big box store. Wipe and then apply a moisture cured polyurethane like Master Series Silver (wait 15-30 minutes between coats) or Eastwoods Rust Encapsulator. Mix it and brush it on.

5. Another suggests: clean it as much as possible, a grinder is best or a wire brush on a drill motor. Sand it with 180-220 until you see some shiny metal. Wipe it all with alcohol or acetone, THEN apply a converter like Navel jelly, OSPHO, or Picklex20... all are phosphoric acid based, then clean and apply a good rust sealing paint.