Distinguishing different types of plywood is tough enough. Now there's MDF, OSB and particle board also. Today you'll learn about woods that are new, what they're for and what they do. New "reconstituted-wood products" are made by mixing wood leftovers with glue or resin at high levels of heat and pressure. The result is strong wood panels without a grain that do not bend bow or warp -- as regular plywood does. One of the three most commonly used new types is MDF (medium density fiberboard) -- a smooth surfaced panel made with fine wood fibers. It's used for furniture shelving and cabinetry. Next is particleboard. It's along the same lines, only it's made by mixing coarser sawdust with adhesives. It's primarily used for furniture and countertop substrates and as underlayment. Finally, there's OSB (oriented strand board). It's made with large flakes and chips of wood glued in layers with grains crossing for strength. It's mostly used for sheathing and underlayment. Today, in addition to plywood, you have many new choices. And that's the On The House Tip for today.