Rust Under Vinyl

[bajajoaquin]

There's a lot of periodic discussion about rust under vinyl roofs. A lot of the back and forth suggests that the tops weren't fully prepped and painted, or that blems got the vinyl, or stuff like that.

Looking at my roof with the vinyl off, it appears fully painted, but still has a bit of rust.

Is the answer simpler? The vinyl material is porous and holds water. Therefore, when it rains, or you wash the car, the top holds the water in contact with the metal for longer, and accelerates rust.

 

[commando1]

Is the answer simpler?

What's the question? Why do you have rust despite it being painted?
Almost all the roofs with vinyl on them rusted.Even painted roofs with aftermarket vinyl roofs rusted.

 

[Fratzog]

Here is a guess. Condensation forming when AC on high in hot humid weather? Another thing I noticed on my 68 was the the rear trim over the rear quarter where the clips go through the bottom of the roof was a source of surface rust. I pulled the trim and address the issue before it could spread.

 

[Pete Kaczmarski]

I agree with your comments of vinyl being porous especially when not maintained. But my '78 New Yorker St Regis Coupe had it where the factory drilled the holes for the edge molding and then never treated the metal where they drilled the holes.

 

[CBODY67]

As the vinyl ages and the oils in it evaporate from heat and time, it can become a little porous in nature. Moisture CAN seep through it, over time, as it gets older and the top of the vinyl gets closer to the fabric base under it. Using a protectant can keep the water beading off, as wax does on paint.

In the earlier days of ArmorAll, some recommended NOT putting anything on the vinyl, just soap and water and durability would be enhanced. I don't know that I buy that. There used to be some "sealers" that went on like car wax, but don't know if they really worked, either. Personally, I suspect you'll need to DA sand and repaint the roof prior to covering it with new vinyl. Plus fixing anything on the C-pillar joints and rear window lower areas.

More than just a simple installation of new fabric. As with paint, surface prep is important.

CBODY67

 

[CBODY67]

Our '66 Newport Town Sedan came with a painted top, which was fine. I was in junior high, back then, so the time spent waxing the car was no big deal. I'd stand in the door frames to wax the top . . . ALL of it, being sure to get that center part. A few years later, I determined that if and when I bought a car it would have a vinyl roof. They were relatively "new" and upscale back then, and looked pretty nice. AND nothing to wax up there. I could use a sponge with ArmorAll on it, which was much easier to do!

That "next car" was my '70 Monaco DH43N0D Brougham. Not having to wax and wipe that top was pretty nice! Until it rained and the ArmorAll residue clouded the glass on the outside. Went to the STP product with the '67 Newport CE23 (1981). It had a nicer satin sheen and didn't wash off.

In the end, I like the look of the factory vinyl roofs and the relative ease of keeping them washed and such, but in the long run, a paint roof is a better deal. Just need a wide-rung step ladder! One side issue in favor of the vinyl roof is that it stiffens the roof panel and quietens the interior of the car as a result.

In the 1968 time frame, the "vinyl roof" for the Dodge pickups was sprayed on, with the "seams" being a tape that was put on the roof prior to application of "the texture". Looked kind of like lumpy asphalt, but it was what it was. Ford and GM didn't follow suit, though.

As the fabric on the Monaco is now gone, if I found a good quality and correct grain vinyl roof, I'd consider it, but AFTER the top was fully primered, painted, and any rust issues taken care of. PLUS finding somebody who can carefully remove the drip moldings without dimpling them! That way, it'll be "as built" from the factory.

CBODY67