My mom was complaining that her electric heating pad was so hot it was burning her sensitive skin. She had tried wrapping it in dishtowels, but of course they didn't stay on very well. So I told her I'd make her a cover for it with two layers of batting. Here's what I did. I apologize in advance for the bad pictures, this was a late night project!
Scraps of fabric & batting
package of sew-in velcro
Measure your heating pad. Add 1.5" to the length or width (whichever one has a cord coming out one side) and add 3" to the measurement that does not have a cord. My heating pad was 12.5" by 15" with the cord coming off a 12.5" side. So my new measurement is 14" by 18"
You will need a front and back in this measurement & a layer or two of batting. Since you will be folding over the long side to add a velcro closure, you can cut the batting about 2 inches smaller (14" by 16") to reduce the bulk. I also only added batting to one side, but feel free to do both if you think it will be more useful. Your front and back can be one piece of fabric or any combination of fabrics sewn together. I used Minkee on one side with some trim in Anna Maria Horner Good Folks cotton on one side and her Folksy Flannels on the other.
Now you can pin your front side to the layers of batting to prepare it for quilting. You can see my batting is about two inches shorter than my flannel. I am leaving the batting short at the top because that is where my cord is coming out.
You can do any type of straight line quilting or free motion. I decided I could use the practice and did a little free motion work.
Now place your quilt sandwich and back of the cover with right sides facing in and sew the three sides that do not have a cord coming out of it. I used 1/2" seams with my serger, but a sewing machine will work great too.
Turn it right side out and make sure your heating pad is going to fit inside. Good! Trim the open end to make it even, if necessary.
Fold your open side down 1" and press. Cut a length of velcro (both sides) just a smidge smaller than your side. Pin one piece inside the front & one inside the back (easier done than said), don't worry about where the cord comes out, the velcro just won't connect in that spot.
Sew a seam along the top and bottom of the velcro strips, keeping close to the edge.
Hooray! All finished! Slip the heating pad in and velcro it closed.