Building with imagination

Radio Control Boat Modeler, Aug 2004 by Fryant, John

This month, I want to pass on a couple of building techniques I've used on a new steamboat model I'm building. One involves the use of foam; the other, PVC pipe and acrylic rod. Both might provide ideas and inspiration for you on a future boat project.

I've written about using foam for hulls before, but foam can also be used for other parts of a model. A case in point is the cabin on my new towboat model; it has a curved front and some crown in the roof. It also sits on a deck that has both shear and crown. Rather than frame all this up in wood, I decided it would be easier to form the basic cabin structure out of foam and make the bulk-heads thick enough to also serve as roof supports. I used some high-density white Styrofoam I had on hand. Ordinary pink or blue insulation foam would work just as well, and it weighs a bit less. It's available at most home-improvement stores.

This is a big model; it's built to 1/24 scale. The thickness of the cabin bulk-heads varies from 34 to 13/4 inches. I used three pieces of it: one for each side and a third for the front. The rear of the cabin is flat, and I used 1/16-inch ply for it. I cut out the curved front on my band saw and then used a sanding block to sand it to final shape. I sanded the bottom to conform to the curve of the deck it sits on.

When I was satisfied with the shape of the cabin, I cut out the window openings; the result was a rather sculpted-looking unit. I cut strips of 1/8-inch ply and epoxied them around the top edges of the foam to form the tops of the window and door openings. Had I not wished to light the cabin interior, the entire structure could have been made of a solid foam block with the window openings painted black. I mounted the cabin on a wooden frame, but it's removable to allow access to the boat's batteries and RC gear.

To simulate the wood siding that's used on the full-size boat, I covered the foam substructure with Evergreen scribed sheet styrene. Several types of adhesive will work to adhere the sheet styrene to the foam; I chose 3M Spray 77. Epoxy would work equally well, as would the new polyurethane glues such as Gorilla Glue and Titebond. Spray 77 has the fastest setup time, but you should use it outdoors or in a large, well-ventilated area. Don't use it in a confined shop area, as the sticky overspray covers everything. Don't use any type of plastic cement or other solvent-based glues because they'll dissolve the foam.

I used 0.040-inch-thick, scribed styrene sheets to cover the flat, side bulkheads, but this proved too thick for me to bend easily around the curved cabin front. I laminated the curved surfaces using two layers of 0.020-inch styrene. After I had glued the first layer to the foam, I attached the second layer to it with Testors Liquid Plastic Cement.

With the siding in place, I cut the door and window frames out of sheet styrene, glued them into place and applied clear acrylic glazing behind them. Gluing acrylic to styrene requires the use of Plastruct Bondene clear liquid cement, which is available at most hobby shops. Using foam for the basic structure saved time compared with building it out of wood.

BUILDING A WORKING PILOT WHEEL

Old-time riverboats were known for their large pilot wheels, which were often 6 or more feet in diameter to give the steersman the leverage necessary to turn the craft's big rudders. The large wheel was also very visible in the glass-enclosed pilothouse atop the boat. Riverboat modelers usually delight in detailing the pilothouse interior, as it is so very visible.

I have not yet found a manufacturer of these large-model pilot wheels, so I scratch-build mine-not the easiest task. The techniques presented here may be The techniques presented here may be helpful to boat modelers who wish to make their own pilot wheels. These tips will also work for those who wish to scratch-build ships' steering wheels of any size.

The March 2004 issue of Model Airplane News contains an article on making wire wheels for vintage aircraft using PVC pipe for the rims. This tough, cheap material is widely available, and I thought it would be ideal for the large rim of a riverboat steering wheel. The article shows how to mount a short length of pipe on a hand drill to turn the rims. I'm fortunate to own a 6-inch metal lathe, so this made turning my wheel rim even easier. Rather than buy a length of pipe, I purchased a 2 ½-inch round fitting, chucked it in the lathe, trued it up and cut off an 1/8-inch-wide ring. Before I completed the cutoff, I rounded the top edges with a file. After the cutoff, I slightly rounded the inside edges with sandpaper.

The next step involves drilling 16 evenly spaced holes through the ring for the spokes. The Model Airplane News article shows how to wrap a piece of paper around the circumference of the wheel once and then remove it, lay it flat, and make a series of evenly spaced pencil marks along its length. It is then wrapped around the ring again, and the pencil marks are transferred. This process bit simpler for me, as I have an indexer/divider attachment for my lathe. When the ring is mounted in this, you can rotate it to render a nearly infinite number of evenly spaced locations for drilling. I centered the divider with the ring mounted on it on my drill press, clamped it down and drilled 16 holes through the ring. The holes' size matched the diameter of the music wire I used for the spokes.