Sand Bondo Smooth

What happens here

Allow the Bondo to dry and harden completely. Bondo dries much faster than spackle, but ensure it's fully cured before sanding to avoid gumming up your abrasive. Using a power sander with a vacuum attachment, sand the Bondo until it is completely flush with the surrounding trim. The goal is to remove all excess Bondo, leaving only the filled imperfection, which should now be perfectly smooth to the touch. The power sander and vacuum are crucial here due to Bondo's hardness and the fine dust it creates. If you left too much Bondo, it will require more intensive sanding. Regularly feel the sanded areas to confirm they are flat, as visual inspection alone may not be sufficient. Any remaining nail heads should be flush and filled.

Goal: Once the Bondo has dried, sand it down to achieve a perfectly flat and smooth surface, ready for primer.