Cutting and installing crown molding can be very tricky, especially for a beginner. One of the trickiest parts is getting the mitered joints to line up in the corners. Most carpenters cope the inside corner joints with a traditional coping saw. This allows for a perfect join even if the wall is not square. Traditionally, coping crown or other types of molding is done with a coping saw. This saw has a very thin blade with a bow frame. after you cut a miter for a inside corner, you need to cut with the coping saw along where the miter cut begins on the front of the molding. cutting out and removing the tip of the miter cut and some out of the back of the piece
Using a traditional coping saw can be very difficult and takes a lot of skill and practice. Another method for coping is to use an angle grinder. Angle grinders are very useful for a variety of jobs from carpentry and millwork to masonry and metal work.
To set a grinder up for coping:
-Use two 80 grit sanding discs approximately 4” across.
-Line them up back to back with a grit facing out in each direction.
-Attach them to the grinder as you would with a standard cutting wheel.
-Now that you are set up, you can use the grinder to relieve the back of the crown molding as you would with standard coping saw, but A LOT faster.
Using this method takes a little practice because a grinder is very aggressive. Use a light touch and start at the thicker parts of the wood, moving to the thin tip of the crown moldings very carefully. To finish up the little details of the trim, use the edge of the wheel barely touching the molding.
This method of coping crown molding will save you countless hours and lots of aggravation not to mention coping blades.