I plan to use an old mould in which the surface has seen better days, its chipped in sharp corners etc.

It got me thinking, I can use body filler to repair the damage but this will probably come out with the part when demoulded, or simply fall out anyway as the mould flexes.

So then I thought why not line the entire mould once its been filled and sanded smooth, with the type of film used to wrap cars etc, and use a release agent on top of that, so that the film will flex with the mould when the part is removed, and hold any filler in place in the mould at the same time.

My question is will such wrap material react with the epoxy during the vac process and bond to it or will it remain stable and thus easy to demould afterwards whilst still remaining attached to the mould?

Of course I would de wax the mould before repairing and applying the film.