What are the differences between sanding sealer and grain filler, and how do they affect the finishing process of woodworking projects?

Sanding sealer is a type of primer that seals the wood surface before applying the final finish, while grain filler is used to fill in the pores and grain of the wood for a smoother finish. Sanding sealer helps to create a smooth surface and enhances the adhesion of the final finish, while grain filler helps to achieve a more uniform and polished look by filling in the natural imperfections of the wood. Using both products can result in a more professional and refined finish for woodworking projects.