Take your thin stretchy cloth and use it to wrap around the entire back side of the door panels.
How to fiberglass door panels step by step.
Complete step by step process of fiberglassing the rear deck with 10 and two 6x9 s for the deville with raw footage of painting outrageous in the booth also mail call buckswoodshop from spraywaycustoms candypaint spraywaycustoms howtofiberglass you can use the same process to.
See pics below after cutting the basic shape in wood i sanded the mdf to the shape contour that i wanted for my fiberglass door panels.
Attach the fabric onto the panel using the hot glue.
Remove the door handle if you do not intend to fiberglass it into the door.
Caraudiofabrication shows how to mold the shape of the door panel you will be making the door pods on.
On my panels i decided to delete the door pull pocket and did so by constructing a flat section where the door pull pocket was with 1 2 mdf board and screwed it into the door panel plastic.
Glue a small section at a time as you continue to stretch the cloth over the door panel.
You will be using fiberglass resin chop mat and oth.