This is the same problem I have had with the plastic substrates. When I asked
this question a while back, I did get a reply with several formulae for
solutions that could possibly be used to coat the plastic to get the gelatin to
stick. However of these, the idea of coating the plastic first with albumen
seemed to be the simplest. Unfortunately, I haven't tried it yet. The other
thing that seems to help, is to make sure that the plastic has some "tooth" for
the gelatin to hold on to.
Hope this helps.
- Wayde Allen