A recent job called for me to mill a short run of custom molding to match an existing profile. I roughed out the profile on the tablesaw, but needed a way to refine and smooth the shapes accurately. This sanding block with a mirror-image profile, made from Bondo auto-body filler, helped me do just that.

To make the block, I built a frame to fit snugly around a cutoff of the existing molding. With the cutoff at the bottom of the frame and covered with plastic cling-wrap, I filled the frame with Bondo. When the filler hardened, the cutoff left a perfect reverse impression of the molding’s profile. I then sanded the back of the block flat and added bevels to help hold the sandpaper.

After working the larger molding curves with a handplane and a drill-mounted sanding drum, I began hand-sanding with my Bondo sanding block starting with 60-grit paper and then moving to finer grits. The process took some time, but the result is a perfect reproduction of the original crown molding.

Jim Richey

Fine Woodworking Recommended Products

Woodriver Rechargeable Desiccant Bag

Placed in a drawer, cabinet or closet, the bag immediately begins to absorb moisture from the air, which reduces corrosion.

Buy at Woodcraft

WoodRiver Router Bit Storage Case

Molded from high impact clear ABS, this WoodRiver case provides a strong storage solution to keep your router bits safe and dry.

Buy at Amazon