There are many ways to not do it right. Apart from choosing the best epoxy for deep casting, is good idea to read the documents of the said epoxy and follow them instructions to the letter. best is to call the epoxy manufacturer and speak with them for the most suitable epoxy for the purpose.

Cause at the end of the day they know their stuff and even can mix a custom epoxy for your purpose. I have talked with one company technician and he knew exactly about that situation and explained me the differences between the 3 suitable epoxies they had.