I'm making a memory quilt with my Step-father's poly cotton shirts. They're pretty thin. If I was sewing them together, I'd probably put a fusible interfacing behind each piece. But I'm putting them in a denim quilt, where the denim is sewn together, and the shirt fabric is held down by the denim. So I feel like it's pretty secure. I also feel like, in this type of quilt, I could put about any fabric in with the denim. Here's a picture.