First time doing this and yes I will do a test piece first. Depth is likely 2- 1 1/2 inches. Looking to do river tables and artistic pieces using odd shaped sections of tree trunks that have large voids. Two questions - should the wood be sealed with either a quick drying epoxy, something else, or not at all? Second, there are so many brands out there, do you have one that you think is particularly good? Thanks