Putting additional gasket sealant or gasket maker on a quality gasket is similar to putting ketchup on filet mignon. Each may be good on their own, but where gaskets are involved, they may not be the best combination. There is a variety of gasket makers and flange sealants available and putting gasket maker on a conventional gasket is one of the most common errors of all. These compounds are engineered for specific applications and understanding where and when to use them is important. In some instances, they can keep the gasket from sealing properly. Typically, if an added sealant is needed, the manufacturer will bead the gasket. This controls the amount (height and width) and provides a uniform seal.