Water shield behind door panel?

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20+ Year Stangneter :roc</strong><span class=
Mar 17, 2003
946
20
49
Arizona
I removed my door panels so I could paint them and found that there was water damage on the backside of the panels and also there was no water shield between the panel and the door.

I assume a previous owner removed the water shields. Where can I get new ones? I looked on 50resto.com but no dice :shrug:
 
From the factory, it's kind of like wax paper. The easiest thing to do would be to cut a piece of garbage bag into the general shape and get a roll of butyl tape to hold it on.