Lay the tracing paper on top of the cutting grid. Trace the patterns for the sides of the bean bags onto the tracing paper. Cut out each of the patterns.
For the top of the bean bag chair, create a circle pattern with a 5 1/2-inch diameter.
Fold one piece of tracing paper in half and mark the center of the fold with a pencil. Use the ruler to create the arc for the top piece of the bean bag. Measure 12 inches from the center mark at various angles to create a curved line on the tracing paper. Cut along the curved line and unfold the pattern to reveal a circle-shaped pattern.
Mark a line across the entire diameter of the circle that is 1/2 inch from the fold. Cut along this line as well as the center hold to remove the 1/2-inch strip you have created from the circle.
Use the sewing pins to attach each of the patterns to the selected fabric and cut out each of the pieces from the fabric. You will need to cut out six side pieces.
Use the sewing pins to attach each of the patterns to the muslin fabric and cut out each of the pieces. You will need to cut out six side pieces.
Pin the bottom pieces together along the straight edges of the circle. Use your sewing machine to baste a 1/2'' seam along the straight edge where you have pinned the bottom pieces together. Use an iron to press the seams open.
Place the zipper right side down over the seam you created in Step 5 with the zipper teeth directly on the seam line. Use the glue stick to glue the zipper in place. Sew the zipper in place by placing a straight stitch down the side of each zipper.
Sew the sides of the bean bag together. Sides should be sewn together inside out so that they remain hidden in the final product. Place the stitch 1/2'' from the edges of the fabric. Do not sew the last two sides together yet. Use the iron to press the seams flat.
Turn the bag right side out. Add a top stitch to each of ytheseams, including the final seam. Place the top stitch 3/8'' away from the seams. Press the final seams to create a smooth finish.
Make a stay stitch on the unsewn edges of each side piece. Turn the edge of the side pieces under and make a seam 1/4'' away from the top of the edge. Repeat the process for the top and bottom edge of all six side pieces. Press the seams in place.
Pin the sides to the top piece of the bag and attach the two, using a top stitch that is 3/8'' away from the seams you created in step 10. Repeat this process for the bottom of the bean bag.
Repeat steps 6 through 12 to complete the lining the same way.
Insert the lining into the outer fabric and fill the lining with polystyrene pellets. Zip both the outer bag and the liner bag closed.