I I think that you can used mechanical stirring for mixing the urea-formaldehyde micro capsules with epoxy for doing a good dispersion of the micro capsules before the addition of catalyzer , then take it to the mold and made the addition of the catalyzer and mix for obtaining the thermosetting material.

Mix with the sigma equipment prior to the catalyst. http://www.youtube.com/watch?v=1fWI1MIu80k