To ensure an ultra smooth surface, use Transtar’s Pit-Fill Spot Putty. It is a single component polymer based system that air dries to a sandable, durable finish in minutes! Designed for use in filling scratches, pinholes, low spots, blemishes, sanding marks and other surface imperfections. Pit-Fill Spot Putty has excellent adhesion to bare metal, galvanized, aluminum and over other properly prepared existing finishes. Once cured, it can be sanded to a featheredge and accepts virtually all paint finishes. It features minimal shrinkage and an ultra-smooth consistency.