IIRC epoxy (resin or hardner - unmixed) never really going bad, just that it might crystalize or partially crystalize in the container. It can be returned to it's originally consistancy by placing the can in a warm/hot water bath. From the RAKA user manual (boat building epoxy similar to West): "(6) Epoxy has an indefinite shelf life but can crystallize over time, especially in cooler temperatures. Try to store your epoxy at room temperatures. Never store it in freezing temperatures and don?t store it on a cold concrete floor. Crystallized and freezing exposed epoxy can be brought back to normal with no loss of properties by moderately heating and stirring it. Placing your epoxy containers in a pail of 120 degree water should be sufficient."