Common Mistakes in Exterior Door Refinishing Refinishing an exterior wood door is an excellent way to prolong it’s lifespan while improving its appearance. However, there are a few common mistakes that can render a refinishing ineffective, or even damage your door. Learn what to avoid while working on your exterior wood door to ensure a successful refinishing. 1. Poor Sanding Sanding against the grain or leaving power sander marks can leave unsightly marks on the surface that will appear in the finished product. Pay attention to how you’re sanding, and use finer grit sandpaper to eliminate any marks. 2. Scratching the Glass Leaving glass unprotected during the sanding process can result in accidentally scratching the surface. These marks are difficult to remove, and can be avoided by simply protecting the glass before you sand. 3. Bad Varnish A varnish could be bad for a variety of reasons; bad prep work, mixing incompatible products, etc. Make sure you know the product you are working with, and do not cut corners. 4. Sanding Through the Veneer Many exterior doors are constructed from a solid core with a decorative veneer applied on top. Sanding too far into the veneer can show unsightly layers and seriously reduce the lifespan of your door. Know how your door is made, and don’t sand too much.