Cutting the back panels
First determine the size you will need for the envelope backing. Let's say you are making a 14" square pillow cover. Your back will need to be 14" in length. To determine the width, take that number (14") and divide by two (now you have 7") then add four inches (for a total of 11"). Cut two pieces of fabric 11" X 14".
Let's do another one just for fun using 18" for the square pillow.
18 / 2 = 9 add the 4" overlap 9 + 4 = 13 so your backing panels will be 13" X 18".
Tip: You can use the same equation for any size pillow--just substitute the very first number (18 in this case).
Tip: I find that adding four inches works well, but you can make adjustments if you want more or less overlap. Keep in mind that more overlap makes getting the pillow form into the cover difficult. Less overlap will distort your pillow.
Hem the panels
Fold and press one long side to form a small ¼ inch hem, then fold and press again so the raw edge is completely enclosed. Sew your hem and repeat on the other 11" X 14" panel. In this next picture you can see how the panels are hemmed (blue arrow) and then placed on the pillow top.
Layer the pieces (RST)
You're ready to layer the pieces. Start with the quilted front of the pillow cover. Lay it down on your work surface, right side up. Place your back pieces so that the finished sides of seams are facing down and are in the center of the panel. In the picture above you can see how the sewn edges overlap each other in the center of the pillow cover.
Mark the corners
Before you sew, you'll need to mark the pieces so that you can cut off a bit of each corner. A better way to explain this is to show you the outcome.
Notice how the purple and gold pillow has "bat ears" sticking out? The other pillow looks square. That's because I trimmed the corners to give it the illusion that it's square.
The way to achieve this look is actually quite easy. Begin at one corner of the pillow and measure ½ inch from the corner. Using a fabric pen, make a small dot. Now draw a line from the dot to about ¼ of the way toward the center edge like in the drawing. Draw lines on all four corners. Look at the photo below (yes, it's the same as above). You can see the drawn lines on each corner. Notice that I didn't draw lines all the way around the pillow. That's because I will use my normal seam allowance and don't really need lines. (Or maybe because I'm lazy.)
Sew all the way around the pillow cover, using the drawn lines as necessary in the corners. Just keep a ¼ inch allowance where you don't have lines. Easy peasy! Tip: If you are using your home sewing machine, you should zigzag close to the straight seam to prevent raveling.
Once the seam is complete, trim the seam allowance to ¼ inch in the corners to make turning easier. Tip: Be careful that you don't cut the zigzag stitches.
Turn and Press
All that's left is to turn the pillow cover right side out through the overlapped back. Be sure to push the corners out to get a nice, sharp point. A good steam pressing should do the trick to keep the seams nice and crisp.
When pressing the seams, try not to push down on the center of the pillow so the quilting will stay nice and puffy.
This method also works for pincushions. Just be careful to adjust how much of the corner to trim down. Small corners mean less to cut off!
I sometimes sew and cut the corners just a hair more than ½ inch. It will bring the corners down and make them more square. Be careful, though, too much will give the corners a rounded look. This purple and gold one is a good example of that.
Now it's your turn! Tell me about this tutorial. Is it detailed enough? Did you understand each part or is something about it confusing? Seriously, let me know if you would use it when making pillow covers. I've been thinking of writing a few more tutorials now that I have a little more time, so your feedback is important.