I suspect you're right, but knowing myself I'd quickly get sick of sanding (6 faces with 5-6 different kinds of sandpaper), and I'd want an orbital sander. Then I'm pretty sure you want to polish the surfaces: lots of elbow grease or a polishing/buffing tool. If I had a workshop with space for tools and dust I'd probably go for it, but I'm doing this in the living room of a small apartment.

Here's the process as explained by a reputable epoxy vendor: https://www.youtube.com/watch?v=9-WYOK90KNo