Thanks Dan,

 

I made my original forms from urethane foam.  I skim coated them with micro and then some polyester filler to smooth out the rough spots.  A couple coats of primer surfacer later it was smooth enough.  I sprayed Krylon glossy spray paint over the primer and then waxed it.  It released pretty well.  On some smaller molds, I made them from wood, bondo for any flaws, then painted on epoxy as a sealer.  With the wax, I was able to get them apart fairly easily.  The painted on epoxy works better than the Krylon, but it would take a bunch of it to paint a 3x7 foot mold.  Is Jeffco available in a spray can???  :-)

 

Two of my molds are 7 feel long.  I designed freeform interior panels that have sculpted armrests and taper down to the instrument panel attach points.  Some are much smaller, like carbon fiber seat pans, and magazine pockets for the back seat.

 

I bought some cheap resin at Home Depot, thinking it would be fine for a mold and some of the fiberglass mat.  The resin is easy to work with but too brittle for "real" parts.  But it's about 1/4 the price of Jeffco!  The mat soaks up huge amounts of resin and doesn't bend very well.  I have some pretty sharp curves, 3/4" radius that the mat can't handle.

 

Those are some great ideas to stiffen the mold.  I did a 2 bid layup to make some of the smaller molds and just filled them with the 2 part liquid urethane foam.  I think I'll try the mailing tubes on the long molds.

 

Since I have "workable" molds already, my biggest issue is keeping them straight and getting a clean release.  The first time, some of the Krylon stuck to the epoxy, no big deal, I just sanded it off the piece.  But the mold now needs repair-resurfacing.  Is there a better release agent than the Meguiar's Release Paste Wax I'm using? 

 

I like the idea of a gel coat.  That stuff is thick and should do a great job of smoothing out the small irregularities.

 

Thanks again,

 

Mike