There is a lot more checking than I realized, and I’m afraid filling these gaps by just pouring in epoxy will be difficult. I want to keep the live edge and avoid making a complete deep pour epoxy mold. Some of these gaps go all the way through The 2-in slab. Any tips for me?
The tuck tape is to aid with releasing the slab from whatever you put it on. You might be able to seal the backside with tape, but I don’t know if tuck tape will offer any advantages over duct tape given the tenacity of resin to escape containment and the fairly poor adhesion tuck tape has.
You could try 100% silicone on the edge of the cookie, that would be easy to clean up after. Just make sure you do it on/in something to contain the resin if the seal fails.