Changing out a door knob, adding a deadbolt or changing the position of a door knob can cause an opening or gap where the old door strike was located. The integrity of the door could be at risk if the opening is not filled. Two possible ways exist to fill the hole. Fill the hole with a non-shrinking wood filler or a paintable new wood epoxy. Either process will fill the hole and allow you to redrill or cut in the general vicinity if you so desire.
Remove the door strike and any hardware from the area. Sand the edges of the opening to remove splinters. It is not necessary to create a smooth surface but one that is solid.
Wipe the opening with a lint-free cloth to remove excess sanding dust.
Choose either the non-shrinking wood filler or paintable new wood epoxy. Mix the epoxy according to the manufacturer's directions on a scrap piece of wood, plastic lid or paper plate. Each manufacturer has suggested mixing ratios so follow the instructions carefully. Be as exact as possible when mixing the ingredients to create the longest malleability of the mixture. This will also make sure the epoxy cures and hardens properly. If you are using non-shrinking wood filler, no mixing is required.
Load the end of a putty knife or plastic scraper with your filler. Press the filler into the opening. Continue with this same process until the opening is completely filled.
Place the edge of the putty knife or plastic scraper on the wood just above the filler. Hold the tool at a 45-degree angle and pull it across the surface of the filler to level.
Allow the filler to dry the amount of time recommended by the manufacturer. Different manufacturer's have different drying times so read the instructions carefully.
Sand the dried filler with 180-grit sandpaper until smooth.
Seal the dried filler with a water-based sealer prior to painting or staining.