Here are two excellent options (please follow the links for detailed information and pricing):
1) Clear Coat is low viscosity, solvent free epoxy sealer that cures to a clear gloss finish.
2) The S-1 Sealer is a great alternative for a penetrating epoxy sealer. It is a solvent-based epoxy system that offers a long pot life and can be applied with a sprayer.
Both products are used in wood turning applications as well.