Guide to Working with Plastics: A Primer on Poured Shapes--Laminated Surfaces Move out of the Kitchen

.The same plastic laminates that work so well in the kitchen and bath as easy-care coverings for countertops are equally useful in other rooms of the house, where their sleek surfaces can cover coffee tables, window sills and bookshelves. Mindful of this decorative potential, manufacturers are making the laminates in bold colors, ranging from bright scarlet to deep navy blue; in wood-grain pat terns that faithfully reproduce the graining and color of everything from light oak to Burmese teak; and even in simulations of burlap, slate and leather.

Laminates can be successfully applied over existing laminated surfaces and over virtually any smooth wood. One of their chief attractions is that they permit you to build pieces from inexpensive hard- board, particle board or plywood. Laminates cannot, however, be applied over linoleum or ceramic tile without an Underlayment of wood, although it often is possible to avoid this intermediate step by using laminated panels—large sheets of plastic laminate that come already bonded to hardboard.

Regardless of the surface to which they are applied, plastic laminates are usually fastened in place with one of two adhesives. Both technically are contact cements, which means that the cement is spread on two surfaces, and bonds immediately when the surfaces are brought together. One of the cements is water- based and easy to use; it’s also nontoxic and nonflammable. But its bonding strength is low, so it’s best used for large, flat surfaces. The other cement, far stronger, is petroleum-based and; like all such products, is hazardous. It’s toxic, extremely volatile and explosive.

Before opening a container of this petroleum-base cement, extinguish all smoking materials and pilot light and flip the circuit breakers for fans, refrigerators and other motor-driven equipment in the work area. Don’t let the cement touch your skin, and avoid breathing its fumes. Work in a well-ventilated area, preferably outdoors—although outdoor temperatures can interfere with drying time. The cement bonds best at about 70 F. Hot weather may make it dry too fast, and in cold weather it may dry too slowly and become brittle. Either condition weakens the bond.

Both forms of contact cement are applied in the same way, with a paintbrush or a roller. Normally one coat is enough, but some wood surfaces—especially the end grain of plywood—will soak up the cement and require a second coat. When the cement has dried to the tacky point, the two surfaces are ready to be joined.

Use care in positioning the laminate; once the two layers of cement have touched, it’s virtually impossible to pull them apart. Edging strips and similar small pieces can usually be guided into place without any preliminaries, but larger pieces may need prior alignment. Since the tacky cement sticks only to it self, you can keep the two surfaces separate during alignment by covering them with strips of wood or pieces of wax pa per until they are properly positioned. As soon as the laminate is aligned, slip out the strips of wood or the wax paper and press the laminate into the adhesive by rolling it with a roller of wood or hard rubber, or by passing a wood block over the laminate while repeatedly tapping the block with a mallet.

Most laminates come in 4-by-8-foot sheets, though larger sheets—up to 5 feet wide and 12 feet long—are obtainable on special order. The standard sheet is 1 inch thick, but sheets 1/32 inch thick are sometimes used for surfaces that get little wear, such as the backs of cabinet doors.

A special laminate, called post-forming grade, is useful for installations where the laminate is required to fit over a sharply curved surface. The paper layers in this laminate are not the customary kraft paper; instead, they resemble crepe pa per. For wide curves, such as those on the edge of a round or an oval table, post- forming laminate can be bent while it’s cold. For tight curves, it must be warmed. In factories, where industrial heaters and presses are available, interior curves with a radius as small as 1/4 inch are possible; but when the laminate is heated at home, curves with a radius of less than ¾ inch are impractical. To warm the laminate, a heat gun or a heating iron, tools normally used to remove paint, is ideal.

When applying a laminate to any surface, old or new, make sure the surface is scrupulously clean, smooth and dry. Sand down any rough spots and fill in any indentations with wood putty. If you are re-laminating over an old laminate, cement any loose edges. Break any surface bubbles in the old laminate by hitting them with a mallet. Remove hardware, sinks and faucets from kitchen and bath room countertops, and sand the old laminate to roughen its surface so that the cement will adhere better. Be sure, how ever, to clear away any chips or sanding dust. These not only interfere with the bond but may telegraph their presence in the form of lumps in the finished surface.

The laminate itself is frequently cut as much as 1/4 inch larger than the surface it covers and then trimmed to size after it’s in place. The preliminary cutting techniques for plastics are described. For a neater finish between two laminated surfaces that meet at right angles, the edge is usually beveled. Both the trimming and beveling operations can be done with an electric router or with hand tools—specifically, a flat cabinet rasp and a No. 8 mill file.

--Seating a vertical edge. Brush an even coat of con-tact cement on the laminate and on the vertical surface being covered. When the adhesive is tacky, grip the edges of the laminate in both hands, nestling the edges in the last joints of your fingers so that your finger tips are free to use as a guide in aligning the top edge of the laminate with the top of the vertical surface (inset). Then bring the two adhesive-coated surfaces together, pressing the laminate against the vertical edge, and roll the laminate with a small wooden or rubber roller until it’s firmly seated.

--Rounding a sharp curve. Apply an even coat of contact cement to the laminate and the surface being laminated; join them as far as the point where the curve begins, using the same techniques shown at left. Then don gloves and warm the laminate with a heat gun or heating iron, holding the heat source just above the plastic. When the plastic is pliable—usually in about 30 seconds—pass it quickly around the curve and press it into the adhesive.

--Aligning a large surface. Apply contact cement to the laminate sheet and to the horizontal surface being laminated, using a little extra cement around the edges. When the adhesive is tacky, lay wood strips at about 1-foot intervals across the horizontal surface; the strips should be at least 3/4 inch thick. Place the laminate in position on fop of the strips. Starting at one end, re move the wood strips one at a time, pressing down the laminate as you go. When the two surfaces are joined, roll the laminate or use a wood block and a mallet to set it firmly onto the horizontal undersurface.

--Making a seam. To join two pieces of laminate, trim both edges to meet precisely. Apply contact cement to the laminate pieces and the surface being covered. Join one laminate piece to the base as shown at left. Then align the second piece, beginning at the - seam. Press both pieces into the adhesive, using a roller or a mallet and a wood block to seat them firmly. To strengthen the seam line, cover it with a cloth and run a household iron over the plastic until it’s warm to the touch; use the lowest setting on the iron. This will soften the cement, embedding the plastic more securely.

Choose an inconspicuous location for a seam. Don’t allow the seam to run into an opening, such as the cutout for a sink. Avoid joining small sections of laminate; such seams have a tendency to pull away from the base.

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Finishing the Edges of a Laminated Top

1. Trimming an overhanging edge. If the plastic laminate has been cut slightly larger than its base, remove the overhang with an electric router or a flat cabinet rasp. Fit the router with a flush-trim cutter, and pass the cutter along the over hanging edge, successively shaving off narrow strips of plastic until the cutter’s roller guide comes in contact with the vertical surface at a right angle to the top laminate. Then make one slow final pass, using the vertical surface as a guide, to cut away the last of the excess plastic.

When using a rasp, cut away the excess laminate with light downward strokes. Hold the rasp perpendicular to the edge of the laminate, but move it at a slight angle, covering 2 or 3 inches of overhang with each stroke.

2. Beveling an edge. Put a beveled-trim cutter on the router and adjust the depth of the cut, set ting the cutter so that the bottom edge of the blade falls just slightly below the bottom surface of the laminate being beveled (inset). Switch on the router motor, and when it reaches full speed, bring the cutter gently in contact with the plastic. Move the router along the edge in one smooth pass (left), keeping the roller guide in constant contact with the underlying vertical surface.

To bevel the edge by hand, use a No. 8 mill file, holding the file at about a 25° angle to the edge and moving it downward in angled strokes that cover 2 to 4 inches at a time .