On any piece of wood exposed to the elements, whether it is your front door or the patio furniture, a durable finish is crucial. Sean Clarke swears by a two-step process using a primer and a varnish topcoat developed in the boat business, where they know all about protecting wood from water and weather. The primer he uses, Smith & Company's MultiWoodPrime (also called Clear Penetrating Epoxy Sealer), is a two-part resin epoxy that penetrates the wood, making it resistant to fungi and water damage. It also chemically bonds to the Epifanes varnish, which has ultraviolet (UV) inhibitors to protect the wood for years to come.

from Fine Woodworking #179