How to Patch a Hole in Wood Trim
This Old House general contractor Tom Silva helps a homeowner patch a large hole in painted baseboard molding
1. Cover the floor near the repair with a canvas drop cloth.
2. Cut a 1/2-inch-thick poplar patch slightly larger than the hole in the wood trim.
3. Next, make a routing jig out of two 1x2s and two 1x4 blocks. Be sure the poplar wood patch fits into the rectangular hole in the middle of the jig.
4. Assemble the jig with instant-bond glue. Apply a bead of glue to one surface, then spray the mating surface with an aerosol accelerator.
5. Press and hold the parts together for several seconds until the glue cures.
6. Remove the patch from the center of the jig, then use a random-orbit sander fitted with 120-grit abrasive to sand smooth the front and back of the jig.
7. Hold the jig against the wood trim with its rectangular opening centered over the hole in the trim. Secure the jig with 2-inch finishing nails; leave the nailheads protruding.
8. Install a 1/2-inch-diameter-by-1-inch-long pattern-cutting bit into a trim router. Adjust the depth of cut to equal the thickness of the jig plus the thickness of the poplar patch.
9. Turn on the router, then hold it flat against the jig with the bit protruding into the opening.
10. Slowly move the router in a clockwise direction around the jig. Be sure to keep the bit’s ball-bearing pilot pressed tightly against the inside edge of the jig’s rectangular opening.
11. As you’re routing, have a helper collect the dust with a wet/dry vac.
12. Square up the rounded corners of the routed recess with a hammer and a 3/4-inch-wide wood chisel.
13. Use the hammer to yank out the nails holding the jig in place.
14. Apply carpenter’s glue to the routed recess, then press the poplar patch into place.
15. Very gently tap the wood patch with a hammer until it’s fully seated.
16. Wipe away the excess glue with a damp cloth.
17. Allow the glue to cure for about 2 hours, then sand the patch flush with the random-orbit sander.
18. Force carpenter’s glue into any gaps you see around the perimeter of the poplar patch.
19. Wait for the glue to harden, then sand the patch one final time.
20. Wipe off the sanding dust with a damp cloth, then prime and paint the patch to match the wood trim.