Learn the steps for making scarf joints that conceal the seams in molding.
For the best appearance, moldings should run in one continuous strip from one corner of the room to the next. But when the room is longer than your molding, a joint becomes unavoidable. Your task, though, is to make that seam as invisible as possible.
The slideshow gives you the steps you'll follow to make the joint, but there are several other things you can do to disguise the joint. If you're joining wood that will get a clear finish, join pieces that have the same subdued grain pattern. Joining a wildly grained strip with one that has straight grain will make the difference immediately apparent.
If possible, locate the joint where a bed, bookcase, or other large piece of furniture will block it. That way, the only time you'll see the seam is on moving day. Behind the door is another good hiding spot, but be careful of positioning a joint too close to a corner. A seam closer to a corner than 16 inches may look as if you're fixing a mistake -- not making a planned extension.
Painted scarf joints are easy to conceal, but they still require careful workmanship and sanding. Paint is merely a finishing coat, not a cure for a poor fit.
If you apply stain and a clear finish before cutting the scarf, you won't have to sand the joint smooth. Although this will save the effort of applying the finish after installation, it means that you'll need to spend extra time to fit the joint as closely as possible. Touch up the joint's ends with a stain pen to eliminate the appearance of raw wood.
Drill pilot holes for the nails that will secure the seam and hold the molding to the wall. Don't neglect this step because the glue makes the joint slippery, and the pieces can shift out of position as you're driving the fasteners. Slightly angle the pilot holes so the joint doesn't slide apart when you drive the nails.