How can I contain epoxy while it sets up?
I have built a few and I used casting resin.  i got it from a fiberglass boat builder. it set up very fast but is self leveling.  we let it drip off the sides and cleaned up the edges after it cured with a router and 440 and 1600 paper.  I have encased fishing lures, German coasters etc.  it cures hard as stone and very transparent.  It has to be poured monolithic and quickly.  We use plastic non stick auto body tools to move it around. The results are incredible. Like a 1/4 inch of glass.