Wood Movement

As the joint flexes, or as the wood expands or contracts due to wood movement, the screw threads crush the wood fibers surrounding them.

There are two options for overcoming the problem. The first and best option is to cut snugly fitting wooden joints and select the proper adhesive for your application. In your case, epoxy is a good choice, since the furniture is outdoors. I've had good luck with West System Brand Epoxy (available from Gougeon Brothers, 517-684-7286).

The second approach is to use larger screws. Larger screws with more and bigger threads provide the bearing surface you need to overcome wood movement. Coated deck screws are a good choice, as are confirmât screws (available from The Woodworkers' Store, 800-279-4441). Confirmât screws are designed for use in particle-

OWhen you begin sanding wood with your coarsest grit—let's say 100 grit—angle your sanding strokes at 30* to 45° relative to the grain direction. If you look at the wood under a bright light, you'll be able to clearly see the 100-grit scratch pattern. On your next pass, say with 120-grit paper, sand 30* to 45* in the opposite direction. Any 100-grit scratches left by the previous pass should be clearly visible under the new 120-grit scratches. Keep on sanding with 120-grit paper until you've eliminated the coarser

While the wood continues to move, the fibers remain crushed, resulting in gaps around the threads. The screw becomes loose and weakens the joint.

board, but their thin, deep threads can hold their ground anywhere there's a lot of force. But even these screws can't beat a good wood-to-wood joint.

I reserve screws for the low-stress parts of my outdoor chairs and benches, such as seat slats or back slats. I countersink each screw and brush a little marine epoxy over its threads before I drive it home. After I've driven in the screw, I brush more epoxy into the countersunk hole, to help keep moisture from leaking into the joint. Then I tap in a tapered plug, which fits tighter than a straight plug. (Tapered plug cutters are available from Lee Valley Tools, 800-871-8158.)

Andy Rae AW senior editor scratches, and replaced them with a finer scratch pattern.

Alternate sanding directions each time you change to a finer grit. In each case, eliminate all coarser scratches before you progress to a finer grit. When you're ready to sand with the finest-grit paper, it's time to sand the wood with the grain. Any fine scratches that are left will be obscured by the wood grain.

Sandor Nagyszalanczy AW West Coast editor Santa Cruz, CA

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