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DIY King Starboard Shower Grate

17 Aug

source: http://www.diy-boat.com/index.php?option=com_content&task=view&id=165&Itemid=33

In case you haven’t noticed from the various projects that have appeared in past Boat Refit issues of DIY, I really like King StarBoard. This durable, UV-stabilized polymer can’t be beat for building myriad items: fiddles, spray deflectors, cockpit and shower grates, storage racks, folding seats, swim platforms, rod holders, splashwell, rub rails, nameboards anything that’s usually made of hardwood, normally teak. King StarBoard is totally maintenance-free it won’t delaminate, rot or splinter and requires no painting. Easy to work with using basic woodworking tools and techniques, it’s comparably priced to teak and saves a lot of time in finishing work.

Refer to the DIY Winter ’96 issue for complete step-by-step construction methods for marking, cutting, shaping, drilling, fastening and gluing. StarBoard bonds to fiberglass, aluminum, steel, wood, plywood and itself with StarBond, a specially-formulated two-part urethane adhesive dispensed from a custom cartridge-type gun. It’s a three-component system: dispensing gun (US$50/CDN$87) holds glue cartridges (US$19/CDN$31) and single-use static mixing nozzle (US$1.50/CDN$2.40). When doing small jobs, save the mixing nozzle: squirt out some glue on a piece of plastic and mix thoroughly until colors are well-blended and the mixture is an ivory-white.

Proper surface preparation is critical when gluing. Lightly sand StarBoard bonding surfaces with 120-grit paper, clean with solvent (acetone, Toluene or alcohol), then flame-treat with a propane torch. Practice this technique on a some scrap before treating your finished piece. Working in a well-ventilated area, hold the torch so the flame is approximately 2.5cm to 5cm (1″ to 2″) away and the blue (oxidizing) portion of the flame is on the StarBoard bonding surface (Figure 1). Pass the flame over the surface at a rate of 30cm (12″) per three seconds. Don’t scorch the surface – there should be no visible difference in the treated surface. Ideally, flame-treating should be performed within four hours of bonding. When bonding StarBoard to plywood make sure the wood is dry and clean; fiberglass and steel require a light sanding with 120-grit paper then wiped with acetone, Toluene or alcohol; and aluminum or steel requires removal of surface oxidation and primed.

To glue, place the two cartridges in the gun and attach the static mixer. Discard the first amount of adhesive ejected out the mixer until the mixture is a consistent ivory-white. Apply an even coat of StarBond to each bonding surface (Figure 2), about 8 to 12 mils thick. Spread evenly with a putty knife. Join the two faces and clamp using moderate pressure but not so much that the glue squeezes out the edges. The optimum thickness of cured adhesive is 15 to 20 mils. Clean up any spilled adhesive with acetone.

Depending on the temperature, working time is about 10 minutes, clamps can be removed in six hours, and it reaches a full cure in 24 hours. Because I don’t like to rely entirely on a glued joint, it’s good practice to use a lap, rabbeted or similar joint along with mechanical fasteners that can double as clamps to hold the joint firmly until the glue sets.

A note on maintenance: Be careful when using teak oil around StarBoard as oils can cause permanent unsightly stains.

We keep finding more uses for King StarBoard and shown here are three more. One practical application of StarBoard is spray deflectors (Figure 3). These produce a dramatic difference on “wet” runabouts and cruisers, deflecting the spray downwards, and off the deck. Essentially that’s the purpose of a chine, but often it’s too narrow and requires an add-on piece.

Strong and durable deflectors made of StarBoard won’t require any maintenance or painting, and blend in nicely with the hull. They are mounted on or just above the chine of a hard-chined boat, or on a boat that doesn’t have a chine placed at a height that deflects the spray. Length is normally one-third of the boat, measured at the chine. For example: 1.8m (6′) deflectors were installed on the 6m (20′) Raymond Hunt-designed ’60s-something runabout shown in Figure 3. These were milled from white, 3cm- (1-1/4″-) thick StarBoard, cut wide enough so they don’t look out of place but not too narrow or they’ll be ineffective.

Make a pattern for each side of the hull; it’s likely the hull contours are different. StarBoard is best cut with a table saw or radial saw operating at 1,275 rpm and using a carbide blade that has 50 to 70 teeth. Router the outside edges with a 1/2-round carbide bit. Lay deflectors in position and check the fit. Drill holes for 6mm (1/4″) screws from the inside hull if you have access; otherwise, predrill the StarBoard, drilling slightly oversized holes (in the StarBoard only) to allow for contraction and expansion and counterbore the heads for a StarBoard plug (Figure 4). Prep the mating surfaces, removing any wax from the hull with acetone. You’ll need to seal the fastener holes in the fiberglass. Some professional builders bed screws in 3M Marine 5200 polyurethane sealant, but its ability to adhere to StarBoard is uncertain. But it will stick to fiberglass and StarBoard doesn’t absorb water, so use either a polyurethane or polysulfide sealant. We don’t recommend gluing on deflectors with StarBond, in case you need to replace or reposition them.

The towel rack (Figure 5) mounts onto any flat or curved surface and can be cut to fit towels of any size. Use a jigsaw to cut to the desired shape. To make the cutout, drill 9mm (3/8″) holes in all corners, inside the cutting line, then cut between the holes with a jigsaw. Router all edges with a 1/2-round carbide bit and sand smooth with 120-grit paper. Flame-treat the back edge and prep the bonding surface and apply StarBond glue. (See above for application instructions.) You may have to devise some innovative means of clamping until the glue sets – masking tape works great in a pinch.

A StarBoard shower grate (Figure 6) is easy to clean and won’t mildew or warp. Use your existing grate as a template or make a cardboard one. The grate should fit with a 3mm (1/8″) or so gap on all edges. After cutting from 12mm (1/2″) material, mark the placement of the 2.5cm (1″) diameter holes on the wrong side, arranging them so they are symmetrical, then drill with a holesaw. Router all edges and cutouts with a 1/2-round carbide bit. Smooth edges with a sander and 120-grit paper, if necessary. A desirable modification is the addition of a couple turnbuttons (see DIY, Fall ’96, Page 18) to secure the grate in rough seas. – JM


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