How to Join Two Pieces of Crown Molding Trim How to Join Two Pieces of Crown Molding Trim

What You'll Need
Miter box
Crosscut saw
Power miter saw
Miter jig
Tape measure
Carpenter's pencil
Fine grit sandpaper
Crown molding

Crown molding trim enlivens a room and adds a measure of elegance by covering up the plain intersection of walls and ceiling. In other words, crown molding frames a space. The decorative wood trim comes in numerous styles with varying degrees of ornamentation. Whether painted or naturally finished, crown molding completes a room. Cutting the crown molding to the correct length and angle is the most difficult part of its installation. On occasion, you may find that you need to join 2 pieces in the middle of a wall. Known as splicing or a scarf joint, this task is fairly simple with the right tools. 

Step 1: Take Measurements to Determine Cutting Points

When creating a scarf joint between 2 lengths of crown molding, determine the total distance the trim must span. On the bottom edge of the crown molding, that is, where it comes into contact with the wall, measure and mark where you'll make the cuts. To give an example: if the length of the wall is 15 feet and you have two 10-foot pieces of trim, measure and mark 8 feet along the bottom edge of one and 7 feet along the bottom edge of the other. Offset the cuts so the scarf joint doesn't happen directly in the middle of the wall.

Step 2: Set First Piece in Jig

If using a power miter saw and jig, set the first piece in the jig with the bottom edge against the fence. The top edge of the molding should be on the cutting table. The jig will hold the piece in place with both the top and bottom edges flush against the jig in their respective locations. If you have no jig, you can hold the molding in the same position with your hand while you cut, but again, make sure the edges are flush.

Step 3: Make First Cut

Holding the first section to the left of the miter blade, adjust the blade so it's set at 45 degrees in the direction of your left. Bring the saw blade down (without activating saw) to make sure it aligns with the mark. Remember, you marked the bottom of the molding, so it's facing up in the jig or against the fence. Activate the saw and bring it down smoothly to make the cut.

Step 4: Set Second Piece in Jig

Set the second piece of molding in the jig. To make it work, the bottom edge will still be closest to the blade, but it will be set in the jig or held against the fence to the right of the blade.

Step 5: Make Second Cut

Reset the miter blade to 45 degrees in the opposite direction. Now, it should point to your right. Again, align the blade with the mark on the bottom of the second piece. Carefully make the cut.

Step 6: Check Joint and Adjust if Necessary

Check your work by holding the 2 pieces together. While both are cut to a 45-degree angle, one should overlap the other, thereby making the joint nearly invisible. If the length is too long, measure again and shave off additional length on one side to make it work. Sand lightly with fine grit sandpaper if needed before installing.

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