A down envelope, often called down-proof ticking, is a specialized fabric casing designed to hold loose, lightweight down or feather fill for cushions and pillows. This inner shell contains the fine fibers, preventing them from escaping through the fabric weave or poking through the final cushion cover. A properly constructed envelope also manages the filling distribution, ensuring the cushion maintains a uniform loft and shape.
Selecting Down-Proof Fabric and Tools
Selecting the correct textile is crucial, as standard fabrics cannot contain the fine fibers of the fill. Down-proof fabric is characterized by an extremely tight weave, which creates a physical barrier against the migration of down and feathers. Cotton ticking or cambric are common choices, often featuring a high thread count.
Many down-proof textiles undergo calendering, a finishing process where the fabric is pressed between heated rollers to flatten the yarns and close microscopic gaps in the weave. This process reduces the fabric’s air permeability, ensuring it holds the fill securely.
You will need a sewing machine, durable down-proof thread, sharp fabric shears, a measuring tape or ruler, and straight pins. Use a high-quality polyester or cotton-wrapped polyester thread for its strength and resistance to breakage, which is important for maintaining seam integrity.
Calculating Dimensions and Cutting Pieces
Accurate measurement is the foundation of a well-fitting cushion envelope, requiring precise calculations before any fabric is cut. To determine the necessary dimensions for the top and bottom panels, you must add seam allowances to the finished size of the cushion insert. A standard seam allowance of 1/2 inch or 5/8 inch is typically used on all four sides. For example, a 20-inch by 20-inch cushion requires a cut panel size of 21 inches by 21 inches using a 1/2-inch allowance.
The calculation must also account for the internal baffle strips, which require additional fabric. These strips must be cut to the exact height of the desired internal compartment, plus the necessary seam allowances for attachment. Cut all pieces squarely, following the grain of the fabric, to ensure the finished envelope does not distort when filled.
Sewing the Outer Shell
Construction begins by joining the main fabric panels using a seam type that offers maximum security against down leakage. A French seam is an excellent choice because it fully encloses the raw edges within the seam, creating a double barrier. Alternatively, a double-stitched seam provides added reinforcement and strength.
Sew the top and bottom panels together along three of the four sides, using the chosen seam allowance and technique. Backstitch securely at the beginning and end of each seam to lock the stitches. One side must be left partially or fully open for baffle installation and final filling. Position this opening on the side least visible on the finished cushion, such as the back or bottom edge.
Creating Internal Baffles
Internal baffles are the defining feature of a quality down envelope, serving as internal walls that divide the casing into separate compartments or channels. This structure prevents the down from shifting and clumping at the edges, which maintains uniform loft and support. The baffle strips are cut from the same down-proof fabric and are typically the same height as the desired thickness of the finished down compartment.
To install the baffles, sew the strips along their length to the interior surface of the top panel, using a straight stitch and a secure seam allowance. The placement must be carefully measured and marked to ensure the resulting compartments are evenly sized across the entire surface. Once attached to the top panel, align the assembly with the bottom panel, with the baffle strips standing upright between the two layers.
The free edge of each baffle strip is then sewn to the corresponding marked line on the bottom panel, creating a series of parallel channels or boxes. This requires careful manipulation to ensure the baffle strips remain straight and taut without puckering the main panels. Precision in stitching is paramount, as any gaps or weak points in the baffle seams will allow the down to migrate between compartments, defeating the purpose of the construction.
Filling and Closing the Envelope
The final stage involves carefully filling the envelope with the down or feather mixture and securely closing the remaining opening. Because down is light and prone to floating, conduct the filling process in a contained space to minimize mess and loss. Using a large funnel or tube inserted into the opening helps direct the down cleanly into the internal compartments.
Distribute the down evenly into each baffle channel, ensuring a consistent amount of fill to maintain balanced loft. Gently shaking and patting the envelope helps the down settle into the corners. Once filled, the remaining opening must be closed with a durable, secure stitch to prevent leakage. A hand-stitched slip stitch provides a clean, invisible finish, or a zipper can be installed for a professional, re-fillable option.