Cutting, Shaping, Finishing

By Jan Mundy

FIGURE 1 Finish sanding any uneven edges with 120 grit paper.

When transferring cutting lines and reference marks, use chalk or a wax fabric pencil (sold at sewing supply stores). Keep the pencil sharp to a chisel point with a knife so a thin cutting line can be made close to the edge of the pattern. Do not use pencils or pens which leave a permanent mark.

FIGURE 2 To countersink screw heads, use a combination bit that drills and countersinks in one operation.

The front of the material has a protective masking that should be left on until the work is completed. I prefer to work from the wrong side, but this involves reversing the pattern, matching the two wrong sides together. King StarBoard’s uniform color lets you lay out the pieces so there’s little waste. (Save offcuts to make waterproof cleats, turnbuttons, shims, spacers and the like.

Cut King StarBoard with a table or radial arm saw, using a carbide blade with 70 to 80 teeth. A jigsaw with a 10-teeth-per-inch blade also gives a clean, smooth edge that requires little finishing. King StarBoard performs best under high-speed cutting, unlike Plexiglas which melts unless it’s cut slowly.

King StarBoard has a very fine, sharp edge that must be rounded with a file, sander or a router, if you have one. A 1/2-round carbide router bit or a decorative bit such as a double bullnose gives the best edge finish. Finish sanding any uneven edges with an orbital sander and 120-grit paper (Figure 1) . Always wear safety goggles when cutting or shaping and a mask when sanding to prevent inhaling plastic dust.

FIGURE 3 To prepare the King StarBoard for gluing, pass a propane torch over the surface so the blue portion of the flame just kisses the surface.

Use a brad-point bit to drill the material to prevent drill travel. For holes larger than 1/4" (6mm), drill a pilot hole first. Drilling heats up the material — especially if you’re using a drill-mounted holesaw — leaving a rough edge on the underside that can be removed with a utility knife or file. Because King StarBoard contracts and expands with temperature changes, you must drill oversize holes for fasteners, adding 1/32" for every linear foot of length or width. Screws can be countersunk (Figure 2) or counterbored and the holes filled with plugs cut from King StarBoard with a plug cutter.

FIGURE 4 After treating the surface, apply 8 to 12 mils of StarBond adhesive to both surfaces with a specialized dispensing gun.

King StarBoard bonds to fiberglass, aluminum, steel, wood, plywood and itself with King StarBond ®, a specially formulated two-part urethane adhesive dispensed from a custom cartridge-type gun. Bonding surfaces are lightly sanded with 120-grit paper, cleaned with solvent (acetone), then flame treated with a propane torch: Pass the flame over the surface at a distance of 2" (5cm) or less at a rate of 12" (30cm) per second. (Figure 3) Don’t scorch the surface. (It’s a good idea to practice first on a some scrap.) Ideally, flame treating should be performed within one hour of bonding. StarBond adhesive is then applied to both surfaces (Figure 4) and spread evenly with a putty knife or old slot screwdriver. Clean up any spilt adhesive with acetone. Because I don’t like to rely entirely on a glued joint, I recommend using a lap, rabbeted or similar joint along with mechanical fasteners that double as a “clamp,” holding the joint firmly until the glue sets. Depending on the temperature, StarBond’s working time is about 10 minutes, clamps can be removed in six hours and it reaches a full cure in 24 hours.