You can find these foam inserts in the foam and pillow filling section of a craft store. You can reuse an old chair cushion, as long as it is box-shaped with a defined height. Don’t use a plain, old pillow for this.
For example, if your seat was 24 by 14 inches (61 by 36 cm) your final shape would be 25 by 15 inches (64 by 38 cm). Make the corners of your top and bottom panels rounded, if desired. You don’t have to do this, but it will make the panels easier to assemble. If you want to use a different fabric, choose anything woven that doesn’t have stretch, like linen or cotton broadcloth. Otherwise, it will stretch out and look saggy over time. [3] X Expert Source Mia DanilowiczMaster Tailor Expert Interview. 8 January 2021.
24 + 14 = 38 inches (97 cm) 38 * 2 = 76 inches (190 cm) 76 + 1 = 77 inches (200 cm) final length
Backstitch when you start and finish sewing to make your stitching stronger. This is simply where you reverse the sewing machine for 2 to 3 stitches. Match the thread color as closely as possible to the fabric. For a nicer finish, press the seam open with an iron. Use a heat setting that’s appropriate for the fabric that you are using. This will typically be “cotton. "
Make sure that the right sides of both fabric pieces are facing each other. Place the seam on the loop in the middle of 1 of the top panel’s straight edges. If you rounded the corners of the top panel, cut 1⁄2 in (1. 3 cm) V-shaped notches into them. This will reduce buckling.
Remember to backstitch when you start and finish sewing, and be sure to remove the pins as you go. If you rounded the corners of the panel, don’t pause and turn the panels, or the corners will be too sharp. Instead, sew slowly, following the curve as best as you can.
If you cut V-shaped notches into the corners for the top panel, you should cut them here as well. The width of the gap depends on the size of your cushion and zipper. Plan on using a zipper that is 3 to 4 inches (7. 6 to 10. 2 cm) shorter than your cushion.
Be sure to backstitch and to remove the pins. For a nicer finish, sew the zipper deeper into the case, so that the teeth are 1⁄2 inch (1. 3 cm) from the edges of the panels.
This method may work for round pillow shapes as well.
Be sure to measure across the front of your pillow, from seam-to-seam. This will give you a nice, snug fit. If you prefer a looser pillowcase, add 1 inch (2. 5 cm) to each measurement first. Choose a fabric suitable for the purpose. Canvas twill will work great for an outdoor cushion. Home décor fabric will work better for an indoor cushion.
Do not pin the zipper in. You need to sew and press the seams between the panels first. An invisible garment zipper will work the best, but you can use a non-separating garment zipper too.
Backstitch whenever you start and finish sewing. This is where you reverse the sewing machine for a few stitches. If you want to, use a basting stitch between the 2 marks. This will make pressing the seam open easier; you will remove this stitch later.
Be sure to press open the seam between the 2 marks as well. Use a heat setting that is suitable for the fabric that you are working with. Most irons will have labels, such as “cotton” or “linen. " If you are using an invisible zipper, the zipper head will be facing you. The zipper pull/tag will be against the fabric.
There is no seam allowance when you use a zipper foot, since the foot will do it for you. A zipper foot looks like a regular foot, except with 1 side missing. This “missing” side should be against the zipper teeth. If you sewed a basting stitch earlier, use a seam ripper to take it out after you finish sewing.
When you reach a corner, pause the sewing machine, lift the foot, and turn the panel. Set the foot down again and continue sewing. Do not sew straight across an edge, cut the thread, and start sewing again. You want to turn the fabric and sew in a continuous line. For a more durable finish, sew the edges of the panels with a zigzag stitch. This is especially important if you plan on washing the cushion covers later.
Use a knitting needle or a chopstick to push the corners out further, if needed.
This method works the best for plain pillow inserts, like that you’d toss onto a couch. It is not suitable for box-type cushions that have a height dimension as well.
When measuring your pillow, be sure to measure across the front, from seam-to-seam.
Use fabric scissors to cut the material. You only need 1 piece to make the entire cushion.
Use a heat setting on your iron that is suitable for the fabric that you are using. Alternatively, you can fold and press the narrow edges by 1⁄2 inch (1. 3 cm) twice. This will give you narrower hems.
You shouldn’t have to use sewing pins for this step, because the pressing caused by the iron will keep the hems down.
The fabric should now be about the same width as your pillowcase. If you need to, overlap the narrow edges more or less in order to ensure a good fit.
Remove the pins so that you don’t ruin your sewing machine’s needle. If the fabric frays a lot, go over the raw edges once more with a zigzag stitch. A backstitch is where you reverse the sewing machine for a few stitches. It makes your stitching stronger and prevents unraveling.
If you need to, use a chopstick or knitting needle to poke the corners out further after you turn the cover right-side-out.
