When sealing wood with epoxy (MirrorCoat, Clear Coat, Silvertip, or General Purpose), it is important to seal the entire piece in a single application to help prevent warping or possible deflection of the wood. Aim for a thin film of epoxy with your seal coat in order to prevent any runs, drips, or sags. A good estimate of how much epoxy you need is to measure 1/2 ounces per square feet. The best way to apply a seal coat is to use a 1/8 Nap Foam Roller.
Typically, the bottom will be sealed first. Immediately after applying the seal coat to the bottom, flip the board over onto a point support system (small disposable cups or a sawhorse works great). Next, seal the top of the board, followed by the edges. Any excess epoxy can be wiped away to prevent drips. Allow the epoxy to gel overnight and then inspect the wood. If any dry spots are noticed another seal coat will be needed.