I just cast 4 sets of decoupage stamp pens and noticed that some of the colors in the stamps bled a bit, Red stamps turned pink and some lost detail. I used 5 coats of Mod-Podge and allowed it to dry for two days after the final coat thinking that would seal everything and they looked fine prior to pouring the PR. Any ideas? Should I cover the finished tubes with a coat of thin CA prior to casting or what...?