A porous plate used in a fuel cell is sealed with an essentially 100% active material and catalyst mixture. The mixture is absorbed into and fills essentially the entire void volume provided by the pores. The mixture is then thermally shocked to partially cure the mixture thereby preventing wicking. The partially cured mixture is then post cured by elevating the temperature such that the catalyst initiates free radical polymerization. Since the sealant is essentially 100% active, there are no escape paths formed during the curing process, and the final seal is essentially 100% leak proof.