I made some heating pads for Holiday gifts and for myself. I searched several tutorials online and found one I like on this Ms.Abbie's blog "The green wife". After I made one following her tutorial, I wanted to change some parts of it to make the process more simple and easier for myself. So this is the Heating Pad Harujion Version.
My tutorial is here in my Flickr set "Heating Pad Tutorial Harujion Version". I hope it would work for you as well. Happy warm sewing!