I am having finish issues on my pattern and mould when using Unimold gelcoat. The first time the part was finished in clear lacquer form Halfords. The part was easy leased and then waxed 8 times. When de-moulded the finish on the part had alligatored leaving a poor quality mould. The second time had 2k lacquer finish, again easy lease and wax with the same result.

The problems sound to be in the preparation of the plug rather than the release agent or the Uni Mould.
The styrene in the Halfords rattle can clear will have caused the problems on the first mould. My guess is you tried to correct that on the second attempt by using 2k clear. 2k can take weeks to fully cure at low/ambient temperatures. If you try to pull the mould too soon the heat generated during the exotherm will soften the 2k which can cause surface finish and release problems

Using an Epoxy gelcoat is an expensive way of trying to fix the problem. You will have to use epoxy resin and either powder pound CSM or E glass for the backing layers. Even then the heat during curing will soften the 2k if its not fully cured.

How you apply the gelcoat also matters. Apply it too thick or add a second coat too soon and it will contract during curing, again causing problems.
If you get the plug prep right a semi perm release agent and correctly applied Uni Mould works fine, I use it all the time.

Warren

Carbon Copies Ltd