Fiberglass Mold

First, we'll make the "plug" (what you make your mold from to get the shape).  If you want a shape other than the original, it's probably easiest to do this first.  Gather some bits and pieces that'll give the shape desired, and tape these to your panel.  Once you have the shape you want, tape it completely off, then use some spray glue and lay down foil over the top.  The foil is a good mold release, and there's less cleanup than wax.  Be sure to mask off all the surrounding areas first, for obvious reasons.  Lay fiberglass over this plug no more than 2-3 layers at a time.  If you do more than this, it can get too hot and warp.  Once you have 4 or 5 layers, it shoud be strong enough to hold shape.  Remove your mold.  Now, clean up the inside and get it all nice and smooth- sand where you need to, and use filler where you need to.  The smoother the better- which in turn means less cleanup on the final piece.  Once you have it the way you desire, smear some car wax inside the mold, and have your way with the fiberglass again.  4-5 layers later, pop it out and clean it up.  Now you can finish your new creation as you wish.