How to Sew a Baffle-Box Comforter

Add 20 inches to the length and width of your mattress (see Tips for mattress measurements). Purchase and cut two pieces of fabric to this size, utilizing the highest-quality wide muslin or quilt-backing fabric available, both of which generally run 110 inches wide.

Fold one length-side of each piece of fabric to the back by a ½ inch. Pin the fold and sew a ¼-inch-wide seam along that one side of each sheet of fabric.

Spread one of the fabrics out on a flat surface, with the pattern or front of the fabric facing up. Mark a 1-by-1-foot grid over the face of the fabric, using a tape measure and water-soluble fabric marker to form horizontal and vertical lines.

Layer the other piece of fabric over the grid-marked fabric with the two hemmed sides resting over one another, and the patterned sides facing in. Align and pin around all four edges. Sew a ½-inch-wide seam along the three sides that are not hemmed.

Turn the material right-side out and pin the fabric together along the grid lines that mark the width of the fabric. The width lines run from the open, hemmed length side to the opposite length side. Sew along each width line, removing the pins as you go, to form parallel channels between the layers of fabric.

Stuff the individual channels with your filling material as full as you want them to be. Distribute the filling evenly along the entire length of each channel. Pin the open side of the comforter closed once you are certain of the fullness and thickness of the bedding and don't want to add anymore. Sew the open side closed with a ¼-inch stitch over the existing stitch lines.

Sew across each of the length grid lines to close off individual boxes of the comforter, locking the filling into place. Fill a spray bottle with water. Mist the surface of the top fabric to wet the grid lines and make them disappear. Don't soak the comforter. Wet the lines again where marker reappears after drying.