A bunch of good answers given.
i’ve been tying for about 50 years been doing poppers for about 30... Not that that means anything in this day and age with the Internet and YouTube anybody could be an expert in a week.
if you’re using the soft squishy type foam I always hit it with some 600 grit to get rid of the fuzzies. Then I use liquid fusion as a base. Then paint my body with paint, cheap acrylics from Michael’s or hobby lobby. Then another base coat of liquid fusion thinned with water,
this is to help getting that nice smooth body and protect your underlying paint when you make mistakes at the next steps(you will)so you can just wipe the paint off without smearing the coat underneath...Every time you put a new color on such as making dots or eyes put a coat of liquid fusion over it and if you mess up you can wipe that off immediately without disturbing the other colors.
in my personal experience all epoxies eventually end up cracking if your poppers last along time. Liquid fusion will not give you that super high shine glassy look like Epoxy does But it seems to last longer than Epoxy does to me without all the hassle and mess.
If you want to use epoxy go to Michael’s or hobby lobby you’ll find 30 min - 2hr epoxy there.
or go online to BSI(Bob Smith industries) They make the best CA glues and Epoxy there is.
They make epoxy just for foam that stays flexible....I haven’t personally used that epoxy though.
Come back and show us how you did plenty of YouTube videos on it and the Stippled Popper has some really good tutorials and information how to do it right.