i personally use 10 minute epoxy, you could try to get rid of the bobbles by hearing the epoxy with a heat gun or just stir the mixture very very slowly but still making sure it mixes, that's what i do now a days and i get hardly any bobbles, Envirotex and casting resins wont work here if your no using a mold. also if you have access to a pressure pot you can always collapse the bobbles under pressure, those things tend to be rather expensive and "normal" lure builders usually don't have them.