Casting resin can mean a couple things, either a clear resin used to encapsulate small objects like coins , flower etc. or a resin like smooth-on that can be used to make lures using silicone molds it's is not clear.
Solarez is clear and used as a sealer and or topcoat kind of the same way as epoxies but it cures almost immediately under UV light. It works great as a sealer, but as a topcoat it isn't crystal clear as epoxie.
For topcoat epoxie look up Envirotex here or on the web.