Here’s an example in full scale:
You will need the following:
- square strip of basswood with a thickness that measures at least the depth of your dentil molding --the distance it extends from the wall toward the ceiling (mine was about ½” by ½”). A scrap about 2 inches long should be enough.
- Cornice molding (the kind without the dentil trim) OR if you have saved the little cut off miter corners from previous mitering you can use those.
- Optional – tiny 1/16 x 1/16 square molding or scrap wood to fill in the open square that forms at the bottom of the mitered triangles (you’ll see in the photos).
- Miter Box such as the Midwest “Easy Miter” and razor saw. Saw should be very fine – for delicate cuts.
Cut the larger square molding to a length just a tiny bit longer than the height of your dentil molding (mine was about 5/8 inch). Cut two of these the same length for two corner blocks.
Looking at the photos, cut two tiny pieces of the cornice molding at opposite 45 degree angles (the two should be mirror images of each other – or use the scraps from previous miters). They should be just tiny triangles with almost no length – each has a 45 degree cut and a straight or 90 degree cut. Be very careful you don’t break off the fragile bottom lip (if it does, just let it break off on both pieces, it should still look fine without it). Cut a second set If you are doing two back ceiling corners.
Glue the two angled pieces to each other, angle to angle, then glue the flat top of them to the end of the square block. It should look like the photo below.
If desired you can fill in the open area with a scrap of 1/16 by 1/16 square molding.
After it dries, sand if necessary and paint.
Glue the blocks in the corners and then install your dentil molding using straight cuts. Finished! Now you have an excuse to save all those miter scraps!