Miter Saw Protractor:
There is a reasonably inexpensive tool which will help you to determine the exact angle between adjacent walls. A miter saw protractor, as shown in Figure 7, is designed to calculate the exact angle of two adjacent surfaces, walls to walls, walls to floors and walls to ceilings.
Figure 7 - Miter saw protractor
It is important that you place the miter saw protractor in the exact position on the wall where the miter joint will be made. You will find that the angles in the middle of the wall are slightly different than the angles at the top and bottom of the wall.
If you cannot find a miter saw protractor at your local big box home improvement center you can order one on line.
Crown Molding Cutting Jig:
Many home handymen have problems in seating the crown molding against the fence of the miter saw in order to make the necessary miter angle cuts.
Figures 8, 9 and 10 show the crown molding cutting jig. It is easy to use and will hold your work in the exact position for mitered cuts.
Figure 8 - Crown molding miter saw cutting jig
Figure 9 - Crown molding installed in the crown molding miter saw cutting jig
Figure 10 - Crown molding being cut using the crown molding miter saw cutting jig
Crown Molding Clips:
It can be very difficult to install crown molding due to the length of the pieces. You need to support the center of the piece while you nail the ends. If you are dealing with pieces that are longer than 6 feet this can be a very frustrating exercise. There is an alternative to having a helper!
Crown molding clips, as shown in Figure 11, will support the weight of the crown molding as you are nailing the corners, as shown in Figure 12.
Figure 11 - Crown molding clips
Figure 12 - Using crown molding clips
If you cannot find the crown molding clips at your local big box home improvement center you can order them on-line.
Styrofoam and Polyurethane Crown Moldings:
To help make the corners look clean and neat many manufacturers of Styrofoam and polyurethane crown moldings have created inner (Figure 13) and outer (Figure14) corner pieces.
There is still a requirement to have the straight pieces meet with the corners, but it is much easier to do that than create the actual corner. Some back shaving with a razor blade knife may be necessary to get the pre made corner pieces to sit tight against walls and ceilings in the corners.
Figure 13 - Inside Corner
Figure 14 - Outside Corner
Installing crown moldings in rooms that have textured or popcorn style ceilings can be very difficult. For the best appearance, crown molding should sit flush against the ceiling.
Additional information on removing popcorn and textured ceilings.