I have a few friends that make lots of t-shirt quilts and I've made a couple myself. I really don't think you should be using heat and bond. You should probably using a really light weight iron-on interfacing that you would use when sewing garments. The idea is just to keep the t-shirt from stretching. Buy a small piece of interfacing and try it on some of the t-shirt scraps; I think you'll find that it's much softer in the quilts and MUCH easier to quilt.