Good morning,

I tried to seal a wooden master part with a view to then creating a vac-cast mould.
It was a disaster - the wooden part totally got stuck and was destroyed when I opened the set mould..
Can anyone suggest the best way to seal a plywood master, so that it can withstand the moulding process.
I previously used about 10 coats of Mirror glaze on a very smooth wooden surface and thought this would do the trick...but no.
Thanks,
Adam

The problem is wood is porous so wax on its own may not be enough to seal the surface fully.  The best way for moulding would be a thin brush layer of epoxy.  Epoxy tends to soak in quite well and as long as the surface has an even coating, will seal it nicely once cured.  If you use something like our XCR Epoxy Coating Resin then you can sand it and polish it flat reasonably well.

If dimensional accuracy isn't too important, then look at the Pattern Coat Primer as it is even easier to sand and shape but is a bit more high build than a thin coat of resin.

Once the surface is sealed, you would be able to use a mould release agent and then should have no problems getting a good release with a casting resin.  I would probably go for a chemical release agent when resin casting due to the ease of application and slightly easier release.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant