: I have a male seat mold made from a plaster cast of a Valley seat. It's epoxy
: and fiberglass coated. I've lent it out and it always comes back damaged
: from people who have used mold release wax and have "experience"
: with molds etc. PVA mold release or wax is no guarantee that your casting
: is going to slide off the mold. I've seen fiberglass shops who do it
: regularly with hammers trying to get the castings off.

: Now what I do with my seat mold is apply a thin coat of Vaseline. Then I lay
: a layer of Seran wrap over it. The Vaseline makes sure it doesn't slide or
: lift up. Once I lay up the glass I watch it carefully and pull it off once
: the epoxy hardens. If you go away on vacation, you may never get it off as
: the epoxy gets rock hard and shrinks. The seran wrap may produce a few
: wrinkles in the casting but I fill them with epoxy putty and sand it out.
: I mix graphite in my mix to make it black.

Yeah, sometimes getting a part off a mold is the pits. Usually worse if the part/mold have fairly straight sides (no relief) but can stick sometimes even if you do everything perfect. Helps if the part is removed as soon as the glass sets up hard since it'll shrink a little as it cures and that only makes the release more difficult, specially over a male mold. Good idea on the vaseline and saran wrap, sounds kinda kinky though . Since it's a male mold might substitute mylar (window insulation) for the saran wrap since it can be heat shrunk, should give a nice smooth finish and is a decent mold release itself.

Bill H.

Bill H.