Going down this route as the clear perspex type of material I got hold of tuns out to be styrene based and melts with polyester resin so wondered if I can use Masonite I think called hardboard in the UK will spray with 2 pack lacquer (polyester) flat and polish has anyone used this method

Thanks Andrew

the smooth shiney side (if it has one ) is well sealed.
you could get away with a good coat of wax/mold release.

screw holes may be a bit more effort to seal because of the brittle/flakey nature of masonite.

if rough on both sides, the amnount of work to seal and smooth will likely negate any benefits.

any place that sells masonite, probably sells formica too.
or,
a 5 mil sheet of polyethylene that can be put on top of anything.
already smooth and non-stick.

1/2 bag or full?

air gets through masonite - well when i tried anyway and if you have screw holes too..

u tried release mould wax on it - worked for long time - good vacuum?

have a 5 cfm pump so vacuum no problem found a roll of laminater plastic so going to put over the masonite and use mould wax

Thanks for the help Andrew

I used it. Mold release and clear packing tape on the screw holes. Allowed me to screw down the center concave with wide flats on the edges. It worked fine. Used wax with a layer of sprayed on mold release. The purple film stuff. Not sure what it's called.