You can bind your wall hanging with double-fold bias tape, as described in Chapter 13. A much cheaper alternative is to make your own binding. Since you are not trying to bind around any curves, your binding doesn't need to be cut on the bias.
Making Your Binding
Cut your binding strips 2″ wide across the total length of your fabric. You will only need three such strips from fabric 42″ wide to bind your wall hanging.
Sew the strips together. To spread the bulk of these seams across a wider area, make the seams on the bias. To do this, place the ends of two of your strips together, with right sides facing. Instead of putting them directly on top of each other, move the top strip to form a right angle with the other. Sew diagonally across the ends. Trim, and press the seam open.
Press the raw edge of one end of your binding strip under ¼″. Fold the binding in half the long way, wrong sides together, and press along the length.
While mathematically you will only need 6″ of fabric to make your binding, you should still buy ¼ rather than yard. By the time you have trimmed the ends straight, you will likely have less than 6″ and will have to cut your strips narrower than 2″.
Attaching the Binding
With the wrong side of your quilt facing you, find one of the border seams along the bottom of the quilt. Line up the folded end of your binding with this seam. This will make your joining point in the binding less noticeable. With the raw edges of the binding along the raw edge of the quilt, sew just over ¼″ from the edge. When you come to the end of one side, stitch to the edge of the quilt and cut the thread, removing the quilt from the sewing machine.
Fold your binding over the stitching as if you were going to wrap it around the edge of your quilt. At the end of the stitching, fold the binding upward, much like you would to miter a corner with regular binding. Refer to FIGURE 13-1.
Don't pin the binding at this point, however. Simply fold it up, then fold it at an angle to position it along the raw edge of the second side. Your purpose in all this folding is to allow for enough binding to create a neat mitered corner. When you have the binding in a stitching position again, pin it near the previous side.
Begin stitching the second side by backstitching up to the pin. Continue on along the second side. The corner is not complete, but you'll take care of it later. Repeat the process at each corner. Just before you've gone all the way around your quilt, trim the binding to allow for a ¼″ fold to the inside. Match the binding up with the beginning.
Finishing the Binding
Turn the quilt over, and wrap the folded edge of the binding around the edge of the quilt. If you extend the folded edge just barely over the stitching line and stitch close to that edge, your stitching should be on the binding on the back of the quilt as well. When you come close to a corner, see that the binding on both the front and the back have even diagonal folds. Stitch up to the point where they meet, and pivot on the needle to stitch the next side. After you've finished, blind-stitch the seam binding together where the two ends meet.
If you want a more perfect binding and you enjoy hand sewing, follow these same steps, except machine-sew the binding to the front of your quilt. Blind-stitch the binding to the back. At the corners, poke the needle through to the front, and finish stitching the corner there.
Now you know all the basics for making a full-sized quilt.