Fender help again.....

I finally cleaned off the tape gum off my motorcycle fender I want to mold.

NOW…the thing is really flat. Should I take some foamboard, Al duct tape, and hotglue to make a flat flange like Evan did?

Maybe I just need to see some more pics of the mold and part. Should I also use PVA on the foamboard as a mold release, or can I use the semi-perm mold release spray I got from here?

Hey I am very interested in your project, can you post some pics, so I can see what your trying to fabricate.