im going with epoxy and doing the corners and joints on the inside. also going with 1 inch thick ply. screwing every 2.5 inches. im making a drill jig to center the predrilled holes. going with black pigment. still wondering about substrate. ive used sand 2 times before and im not a fan. most likely going with gravel. im gonna check out that corner tool online. 8 bucks cant hurt.
