The door panels have been ruined by moisture, but the apolstry is in great shape still. A previous owner removed the dust and moisture barrier. I can't pay $300 for new panels. I'm thinking of transplanting the apolstry on another matieral for a panel, any suggestions for the material?

 

I would say use some stiff cardboard (unlike the factory stuff). Use the old panel as a template. I don't know where you'd find this "stiff" cardboard, but I can't imagine it being too difficult.

- 89_IROC

 

What I would do...
I would not suggest cardboard, only because you could end up back in the same place if it gets wet. Go to Lowes or Home Depot. Look for some wood about the same thickness as the factory board. Then before you transplant the upolstry on, I would attach the clip holders from the original panel to the side of the wood you want to be the back. Use wood staples, or screws. Once the clips are off the original, make a pattern on the wood using your old one for the door hadle holes and such...

Then clean up the other side of the wood and then reinstall the upolstry. Get some 3M headliner spray glue. 88 or 90 if you can find it. Spray both surfaces, allow to tack and place together. You will place the upolstry on and fold the loose ends around to the back. Once folded I would use stapes to attach them to the board. GM glued it, but its hard to get a glue that will really hold up like the factory stuff. Check the depth of the staples, so they don't come thru the front and thru the upolstry.

If you can get you hands on some replacement plastic or some that is sticky. I had a friend get me some that was like clear vinyl like sign shops use only 10x thicker. Put it on before the new panels go on.

Hope that helps.