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Working With Plywood Requires a Different Touch

From From Associated Press

Working with plywood requires different techniques than those used with ordinary wood. Here are some tips for cutting, installing and finishing plywood:

Before You Start

Before using plywood panels, store them off the floor in a cool, dry place, preferably for several weeks. Lay them flat on two-by-fours, or stack them on edge on two-by-fours and brace them as they lean against the wall at a slight angle.

Cutting Plywood

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Caution: Always use a sanding respirator and work in a well-ventilated area when cutting or sanding plywood. Hardwood plywood should bear a stamp indicating it conforms to federal Housing and Urban Development standards for formaldehyde emissions. If, when working with hardwood plywood, you experience low tolerance to formaldehyde emissions, use sanded plywood and give it a hardwood stain.

* Plywood can be cut with a power or handsaw. Use a carbide-tipped or special plywood blade with a power saw because the glue in the plywood quickly dulls an ordinary steel blade.

* If you plan to hand saw plywood, place the panel face up to avoid splintering the surface. Make sure it is well supported. Score the face ply along the cut line with a utility knife. Make lengthwise cuts first. Holding the handsaw at a low angle, cut along the scored line.

* To avoid splintering the face ply when sawing plywood with a table saw, also position the panel face up. Adjust the table saw so that the blade clears the face ply by a quarter inch.

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* When using a portable circular or saber saw, however, put the panel face down. Also make sure it is well supported.

* To prevent a saber-saw blade from breaking when you cut a circle out of plywood, make straight cuts from the edges of the wood to the circumference. Space the cuts about 30 degrees apart. The waste plywood will fall off in sections as you cut the circumference, relieving stress on the blade.

* Be careful when using a power sander on hardwood plywood because you could easily sand through the thin face ply. Never use a belt sander on plywood.

Installing Plywood

* Nails, brads or screws won’t hold in the edges of thin plywood. However, you can sink screws into the edges of three-quarter-inch plywood if you drill pilot holes and center the screws on the edge.

* When nailing into face plies, space nails at four-inch intervals for maximum panel strength. Remove nails by pulling them out straight. If you pull the nails out at an angle, you may cause splintering.

* When using construction-grade plywood for sheathing, make sure the panel grain runs horizontally, perpendicular to the studs. For flooring, the grain should be perpendicular to the joists. In this way, you will get the greatest strength from the panel. To further guarantee maximum strength in flooring, bridge the joists with two-by-fours so that you can nail the panel on all four sides.

Finishing Plywood

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* Before painting plywood, fill gaps in the panel’s edges with plaster spackling compound or wood filler; let the material dry, then sand it smooth.

* If you want to protect the edges from abrasion, cover them with wood molding. Pre-drill holes in the molding, then apply adhesive and nail it on with finishing nails.

* For a real-wood look, you can finish raw plywood edges with wood veneer tape. Some veneer tapes have to be glued on. Others are backed with adhesive, and you apply them either by ironing them on or by peeling off a backing and pressing them on.

Select a roll made of the same wood as the plywood’s face side. Make sure the plywood edge is square, smooth and clean. Remove any dust by wiping the edge with a tack cloth.

* To apply iron-on veneer tape, unroll enough tape to cover the edge’s entire length. Using an iron on a warm, non-steam setting, tack the tape to the edge by pressing at six-inch intervals. Smooth and align the tape as you go.

Finish bonding it by sliding the iron slowly along its full length. After five minutes, carefully remove any overhanging tape with medium-fine (120) sandpaper. Miter corners where tapes meet, using a sharp craft knife. Touch up any unglued spots with the iron. Lightly sand the seams with fine (220) sandpaper.

* Plywood’s distinctive grain can be enhanced by applying a semitransparent oil-base stain. Before staining, treat all edges with a sealant. If you want to paint plywood, first apply a primer, carefully sealing the edges.


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