- After selecting the kit you are going to build, it is time to do an inventory. Open the box, remove the instructions, and lay out the parts. Check the parts list on the instructions with the parts included. If parts are missing, contact the manufacturer about replacement. Leave the parts on the plastic molding trees until it is time to paint or assemble them. This helps to prevent loss of parts. When you have all the parts collected, including additional materials that you will use to customize your model, it is time to begin. Wash all plastic parts with warm soapy water to remove the mold release chemicals. This will help assure that paint will adhere to the surface. Place the parts on a newspaper or paper towels and allow them to air dry. Do not attempt to accelerate drying by placing the parts in direct sunlight, in an oven or by using a hair dryer. The heat from these sources can cause the parts to warp and make assembly difficult, or near impossible.
- When the parts are dried, it is time to plan the assembly. Determine the color pattern that you will apply. Two-tone or multicolor finishes will require layout and masking. Parts that will be enclosed in the interior of the car should be prepared, finished and assembled before enclosing them inside the car body. The painting and finishing of a car will make the biggest impression on the observer. It is critical that the surface of the car be prepared for the finish that you have selected. Remove all excess plastic molding sprue and flash (those extra pieces of plastic remaining from the injection molding process) from parts with a craft knife and fine sandpaper before beginning painting or assembly. Fill blemishes and unwanted seams and features with model putty and sand the surface smooth. This will reduce the chance of ruining your paint job when weathering these areas. You also can add modifications such as "frenched" (1940s through 1960s recessed custom car) headlights, hood scoops, air vents, spoilers and other features at this time. Using glue and body filler, you can make these features conform to the lines of the car. Now also is the time to put dents, holes from metal erosion, and gashes on the surface if you are making a diorama or modeling an abandoned or derelict car.
- After preparing the body, mask areas that should not be painted. Apply an initial coat of primer, sand lightly and followed with a second coat of primer to make the surface ready for paint. Multiple thin layers of paint, with fine sandpapering between coats, will create the smoothest finish. Multiple thin coats of paint also reduce the risk of runs, wrinkles and "orange-peeling." If these paint blemishes do occur, don't panic. Sandpaper the blemish smooth with the finish and apply additional coats of paint until the desired finish is achieved.
- The car assembly starts with installing interior components. In essence, you build the car from the inside out. Make sure mated surfaces are free of paint and finish to allow plastic-to-plastic bonding. Opaque parts can be joined with a variety of model glues. Thin bonding agents and cyanoacrylate ("super glue") are commonly used adhesives. Specially prepared glues for installing windshields and windows, which dry clear, are available at hobby and craft shops and some department stores. The most important technique for assembling your car is to apply minimum glue so that it's not likely to be seen on the finished car.
- Rubbing compounds will remove fine scratches remaining in the finish. A clear overspray finish will give your car the final matte, semigloss or gloss finish you want. Johnson's Future floor wax is often used as a final gloss clear coat to polish windshields, windows and glossy body parts. If desired, weathering can be applied to simulate rust, dirt, grease and other effects. The car can be placed in a glass or plastic display after the final finish is dry. The final appearance of the car is limited only by the amount of time you dedicate to finishing and displaying it.