The first mantelpiece I ever built was just a simple shelf. I used a 6-inch-wide pine board for the shelf, 4-inch crown for the cornice, and a 2-inch strip of pine for the "soffit" beneath the crown. It only took a couple hours from start to finish, but I was very pleased with it. Since then, building mantelpieces has always been a favorite job of mine. I've built fabulously expensive hardwood behemoths and cut-rate specials, but have learned that classy mantelpieces can always be created for a modest investment in time and material. To build the mantel in this article, for example, I bought about $100 of materials from a local lumberyard — mostly MDF moldings as well as