I make custom range boxes for benchrest rifle shooters to tranfer their hand loaded ammunition from their house to the range securely, with a snug fit inside so they dont rattle, and us cerakoted to their choice of colors, themes, or whatever they want so it's personal MTO for them. The inside I pour the heavy, small pelican case with Magic Resin that i also swirl pearls in to customers choice. I never have had any issue with yellowing. It does take a couple days to get hard but so does all deep pour epoxy resin that you are letting cure on its own. Blowing heat on it does help speed up the cure time. Also and this is important, when I mix in my 2 quart mixing cups I use a dry wall mud mixer that is round at the end and is about 2" diameter in my cordless drill to not only be fast, but thoroughly mixed as well