building a mold

[goodwrch]

I made a plug for a console and I have now made the mold, my question is how long should I let the glass cure before removing the plug, I know that fiberglass contines to cure for weeks and weeks after it is laid up. Second question, what should be done to the new mold prior to making a new part, beside waxing of course. thank you for any help

[Eric Sponberg]

Actually, if you have used polyester resin for the mold, it can be removed in a few days since most of the cure is complete by then. It will continue to cure as you use it, by virtue of the heat of exotherm from the parts being laid up in it. Be sure that the mold is properly reinforced for rigidity to hold it in place and stabilize its shape once it is removed from the male form, and for when parts are laid up in it. Stand in on end, not on its side, it will distort less that way.

Eric

[Eric Sponberg]

On the second question, proper waxing with mold release wax, of course, is a must. Use lots of coats, perhaps 6-10 or so. Also, on the first part, you may also want to spray on PVA (polyvinyl alcohol) to insure the first part release without damaging the mold gelcoat. After the first part, with its exotherm, the mold should be stable enough to use with just mold release wax. Rewax prior to every molding.

Eric

[B. Hamm]

Well technically there's only one coat of wax. The reason for putting it on multiple times is to insure that you've not missed any spots. Wax won't build up in thickness you just polish it to a single coat that covers everything evenly.

Bill H.