Door plastic layer under upholstery

[inaminit]

What is the purpose of the plastic layer under the door card? Is it important? Should it be repaired or replaced if damaged or missing?
Thanks in advance.

[faverymi]

Keeps the water vapors moisture from contacting the particle wood panel .

Your door panel will sag or deform over the years.

[andino]

It's a vapor barrier. It often lost to the times but I would recommend keeping them if you have them (or even adding it back) as it protects the cardboard door car from getting wet and deteriorating.

[rwest]

Water from the window running down into the door will rot out the door card if you don’t have the plastic sheet to protect it.

In a perfect world, the door to window seal would prevent this, but alas the world isn’t perfect.

[stevie 77 930]

[fallingat120mph]

Can these still be ordered?

I don't want to cheap out but have some of you found an alternative. I have found sheet of plastic but they are thin and lack substance.


Thanks!
Erik

[blucille]

I found porsche factory parts were readily available for the passengers side. Drivers side was 4x the cost.

One parts supplier had lovely self adhesive vinyl versions. But they shipped me passenger side only, too.

I ended up using one as a pattern and cut some self adhesive shelf liner as an easy fix. Not too sticky, can be removed for access to the door hardware reinstalled at least a few times.

[zuch]

Cut your own out of home depot thick plastic sheeting. You can attach it to the door with butyl tape.

[EC900]

Replace if ripped or missing.
Generally it can be mended if torn, most tapes don’t adhere to poly sheeting, Tyvek does.
Why you need it - If your window rubber wiper seals have shrunk excessively (they all have some space in them) over the years, rain and wash water will flow down the openings at the ends, damage comes from water-soaked door cards, might even mold over if the foam anti-vibration strips on the door card gets wet, and if speaker cones are missing - they’re vulnerable to water damage as well, and not only that, debris will accumulate and block the door drain openings. Good to clean everything thing out.
Once the door cards get wet repeatedly they will crumble from dry rot and maybe even forming mold if they stay wet and warm enough.

The plastic in place also helps deaden a bit of the hollow sound too….I can’t hear my door ‘ping’ anymore. So it’s more beneficial to have this plastic covering than not.

I found mine were missing from a hack job speaker install, door cards were watermark stained but held up w/o any warping. I replaced speaker cones with foam, self adhesive aftermarket type and for good measure put plastic sheet flap to cover them too.

I used some 6 mil plastic drop cloth sheeting (probably the heaviest opaque sheeting available on the shelf) at Home Depot etc., with 10 mil being better. I cut out the pattern and used very tacky Tyvek tape to hold it in place. Even using Tyvek house wrap will work too. Butyl tape is good too, none at HD but I had tyvek tape readily available

Note in my photo, a flap has to be cut and folded/tucked into the lower door void and just beyond the opening, this way any water running down will be directed back inside the door cavity and out the drain holes. - like flashing, it alleviates any chance water gets through and trapped between door card and the plastic sheet, the door sheet metal is stamped and there’s a lip around the upper and lower openings, it seems any water running down would be directed around the opening but looking at the OEM configuration, a slightly longer flap is present.

I believe Pelican has the factory $$ or a generic $ precut sheets available. You just poke the holes where needed and fasten that lower flap. Butyl tape if you can find it by the metal roof section of Home Depot Menards etc.



You can see where the water accumulates near the lower opening and speaker w/o the plastic in place

[jac1976]

With the already ridiculous prices for air cooled parts and now the tariffs (which can exceed the value of the purchased item), I’d make my own.

[silverlock]

Our host has them for $12, pre-cut (both sides): https://www.pelicanparts.com/More_Info/JWSTAPZDPMB.htm?pn=JWST-APZ-DPMB

[jac1976]

Well, they’re from JWest (Texas) so one would assume that there will be no tariff. That said, if they are shipped from outside the country, I’d be hesitant. I bought a dash center vent from a Pelican in Canada for $40. Shipping/fees were around $13. Mid-shipment, I’m notified that I owe $42.37 in tariffs and additional fees. Mind you this is an imperfect used small plastic part for a 50 year old vehicle that will never be manufactured in the US (maybe URO) and the tariff was aver 100% of the value of the part. Even more infuriating, is US Customs documented in the invoice the value was $10.

[jac1976]

Oh, and if they do go through US Customs, they will certainly be “pre-cut.”

[pmax]

Or use a material other than "particle board" for the door card ...

[Hi_Fi_Guy]

If you really want to see what cheap/lightweight looks like, check out some of the postwar economy offerings from domestic U.S brands. What you will find are heat/steam pressed fiberboard interior panels embossed with patterns that resemble leather or fabric then painted to match the actual upholstered items like the seats and armrests. They are very convincing visually, but pity the fool who tries to use Armor-All on this faux upholstery and ends up with soggy, stained cardboard!