If you have a finishing kit, you don't need to apply a sealer because it is in the paint. Let each coat dry thoroughly and lightly sand with fine sandpaper between each coat. Paint in a dust-free area and cover the entire workspace with newspapers or a drop cloth. Let each coat dry completely, then sand lightly between coats. Be careful not to sand through the paint to the wood.
Sealers are available in brush-on or spray formulas.
Check competition rules for local weight limits. Graphite comes in a plastic bottle and on race day is squeezed onto the axles between the wheel and car body. Scales may weigh differently. You might need to adjust your car 's weight on race day. Take extra weights and a screwdriver to the track.