Just use plain old 4 mil sheet plastic from the hardware store.  Salvage the
bump-out for the speaker though.  A nice way to install it is to go to a pro
auto body store and get a tube of mastic that's designed for this.  It stays
sticky and the plastic can easily be removed and replaced.  Or you can use a
good quality outdoor two sided carpet tape.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Marc Perdue
Sent: Friday, July 19, 2013 8:13 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Plastic sheet inside doors?

I have an '87 Westfalia. As you all have realized, I opened up my passenger
door to put in some sound deadening material. Behind the interior door
panel, or card, is a clear plastic, adhesive-backed sheet covering the
door's metal, presumably to keep water from leaking in. Because it's old
and brittle, it's almost impossible to pull it off without tearing it, thus
compromising the barrier. I still need to replace this on my passenger door
and want to find a source before I do the driver's side door and the
slider. Where do you get this material?

Thanks in advance for your advice!
Marc Perdue