Do it yourself

I get asked this a lot, so herewith is your guide to engineered wood products. a. Plywood Plywood is the original engineered wood product. It consists of thin, rotary-cut veneers laminated together with the grain running at right angles. Advantages: versatility--plywood can be made for cabinets, sheathing, underlayment, pressure-treated service, and even marine service. strength and durability--the right-angled grain structure gives plywood a lot of it. Disadvantages: expense--this is the most expensive engineered wood because it is made from large sheets of veneer. b. Particle board Particle board was developed right after World War II. The combined effect of two acts of Congress inflicted particle board on us: the Rural Electrification Act and the Servicemen's Readjustment Act of 1944. (Particle board is in neither, but you'll see what I mean.) Before the Rural Electrification hit, sawmills didn't have electricity because sawmills are invariably in the middle of nowhere. All their equipment ran on steam, and they burned sawdust to get it. After the REA came into effect, mills could use electricity instead of sawdust for fuel--leaving mountains of sawdust on the premises. The Servicemen's Readjustment Act (the GI Bill of Rights) said that every veteran of World War II deserved to have a home. Next thing you know, there's more building going on than there are materials to support. Hmm...we have all this sawdust, we have glue, what happens if we mix the two and pour them into a mold? Presto: particle board. Advantages: cheap. Disadvantages: not strong, and usually falls apart when it gets wet. Louisiana-Pacific makes Redex in California, which is particle board made from redwood sawdust and polyurethane glue; Redex is waterproof. This is probably the first time you've heard of it. Don't worry, you're not missing much--it's still particle board. c. Oriented strand board OSB came out in the 1970s when the forestry industry turned to clearcutting as their standard method of harvest. The small logs this technique brings out of the woods can't be used for plywood or dimensional lumber, but if chipped and glued up with the wafers "oriented" to one another, they're eminently usable. Advantages: makes good roof sheathing and very good wall sheathing. Not as expensive as plywood. Tongue & groove OSB makes good subflooring for vinyl, carpet and laminate flooring. Disadvantages: not span rated for 24" OC trusses. Must be used with 16" OC trusses. OSB subflooring shouldn't be used under hardwood floors. d. Medium-density fiberboard MDF is what particle board should have been. This product is made by mixing very fine sawdust with glue then pouring a pile of this mix into a mold. (A three-foot pile of mix becomes a one-inch board.) Extreme pressure makes a finished board. Advantages: cheap weight, and lots of it--this has endeared MDF to speaker manufacturers. A speaker cabinet made of MDF sounds better than one made of any other affordable material. It's strong. It's cheap. Disadvantages: the two toes I broke dropping a sheet of this stuff on them, for one thing. The edges ding up easily, and it's not waterproof. e. "Masonite" This is the name of the company that invented the product. Its official name is hardboard. To make hardboard, add sawdust to a chemical that dissolves the lignin bonds in the wood. Pour it into a mold and heat it while the board is under pressure, and the chemical is drawn off and recovered. The lignin remains, gluing the board together. Advantages: this is a good cheap board when all you want to do is cover something up. Flip around any Sauder bookcase and you'll find a sheet of Masonite on the back. Disadvantages: this is a weak board, so don't use it anywhere you might encounter stresses, and don't use it anywhere weather can get to it. f. Pegboard Pegboard is hardboard that has a chemical added to it that makes it a little stronger than regular hardboard (so the pegs don't rip it apart) and is formed in a mold with a matrix of steel pins in it. When it comes out of the mold, the holes are already there--they don't drill them. g. High-density fiberboard You will never see this if you don't make laminate flooring. h. Engineered lumber It's late and I'm not going to get into this now. Ask later. This requires a post all its own, but for now salivate over this: there is a lumberyard in Fayetteville that has this in 50-foot pieces. -- --jmowreader