: 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.

I think its not the release agent used rather the technique, when i first had to do with molds i could have used a bucket of wax and still i wasnt able to get a clean cast even if my life depended on it. Then i started a profession that brought me to work with people that had tons of experience with that stuff and they taught me how to properly prepare the mold surface itself to nothing less than a mirror finish and properly wax said surface, each release agent has its own way to be worked with. Its a boring work, specially on very big pieces and people tends to cut corners because of that and to stop at "it should do it".
Plaster tends to be a delicate material to work with in first place and if they get a little rough when the product doesnt come off its no surprise it comes back damaged. The use of hammers and wedges then its justified only on good size pieces and it should be just to clear the edges, not to pop the piece off the mold, compressed air is whats used for that, and even there the outlets have to be on the right spots to avoid suction cup effects.

Your method is perfect for the situation you find yourself in but if you think about mass production or even theatre it takes too much time and work, in those settings preparation is the key.

If you lend that plaster mold a lot you probably save yourself some work (and save the plaster mold too) preparing a silicon copy from a cast of it and lend that one.