- 1). Select the model boat whose hull you want to recreate. Wash the outside surface of the model with a household surface cleaner. Set it aside to thoroughly dry.
- 2). Take a -ounce plastic bowl and coat its inside surface with a light coat of composite material mold-release agent. Separate a 4-ounce chunk of composite mold-making material (or CM3) and place it in the plastic bowl. Place the bowl in a microwave oven and heat it on a low setting for 30 seconds.
- 3). Invert the master boat model onto the wood work surface and wrap it with a small rag so that the model sits level and keel side up. Use a 1/2-inch paintbrush to lightly coat the outer surface of the master boat model's hull with CM3 release agent.
- 4). Cover the master model's outer surface with 1-inch-thick coating of the melted CM3, being careful to force the hot material into every line, hole and crevice. Place the board in the refrigerator for 20 minutes or allow it to cool for two hours. Remove the board and put it back on the table or work surface.
- 5). Peel the rubberized CM3 from the model, leaving the interior of the mold clean and smooth. Examine the interior of the mold and brush out any pieces of CM3 or other debris. Look for any surface bubbles inside the mold, indicating excessive application of the CM3 release agent. If necessary, repeat the process to obtain a good boat hull mold.
- 6). Make a test hull to validate the process and the hull-producing quality of the mold. Paint a light coat of release agent into the interior, concave surfaces of the hull mold. Wait for several minutes and prepare the model-making material that is called for by the model boat hull plans -- concrete, plastic, plaster, silicone or polyurethane. Place the model-making material into the hull mold and press firmly into all crevices, lines and holes. Cut off or press out whatever hollow structure shapes the hull will require when taken to the next step of the model's development. Allow the hull to cure per the model-making material's specifications. Pull out the model boat hull and examine it for alterations or improvements.