The best way to join your baseboard molding in the corners is to cut a coped joint. This is a joint where one of the pieces is cut to be squared and the other is cut to fit over it creating a tight uniformed look. Below you will find steps to helping you with this project.
• Do not twist the coping blade to follow your base line drawing. Keep the cuts simple and remove one small piece then another to follow the curved lines.
• Use an extra piece of trim to practice on first.
• Never use a dull coping saw blade.
Things You Might Need
• 2-penny finishing nails
• Coarse to Medium grit sandpaper
• Measuring ruler
• Extra molding (in case of accident)
1) To get started you will need to begin at an inside corner for the best results. Cut your first piece of baseboard square and nail it into place. Your next piece will need to be cut to length with one end coped to fit over the last one you cut.
2) Now use a miter saw bevel the end of the cut at a 45º angle.
3) With a coping saw held at a 30° angle remove more wood from the back of the baseboard than the front. Try to stay behind the lines you marked when you measured it out. If there is material left behind you can use a sandpaper to file it down.
4) Check your cut. Take the piece down and see if it will line up with the nailed baseboard piece. If you find any spots that are uneven in the cut, mark them and use the sand paper to wear them down.
5) Continue this around the room just as you read above until you have returned to the beginning.
If you are in need of simply cutting the corner wedge for your baseboard molding, you will need to do so like above. First you will need to make sure you have all your safety gear on. Then hold the small piece and cut the wedge at a 45˚angle on both sides of the baseboard piece.
It should look like a small fairly thin piece when you have completed it. Take this and check the size, if it fits snug yet there are no high spots you are ready to place it in the joint. Use the 2-penny nails to secure it in its place. After all this you are ready to paint your baseboard.