you need to use a fusible INTERFACING on knits/t-shirt quilt blocks....it is a totally different product from fusibles like Heat & Bond which is a 'paper backed fusible' used for applique (it bonds 2 fabrics together) an interfacing adds stability to a fabric- keeps it from stretching, adds body. it is the stuff in collars & cuffs, ties, ect. it is a lightweight lining-with fusible on one side.