I read you can use quality craft paper from the arts store for Chinese Erhu type instruments, paper shopping bags for something requiring medium thickness, thick construction paper, or layers of paper if you want a thick banjo head. Some people also use canvas, even an old pair of levis. With paper you have to strengthdn it before you can stretch it. I put diluted acrylic medium in a bowl and dunked the paper only for a second before putting it on a well oiled cookie sheet to dry. Then it can be stretched slightly over the rim. It won't support a bridge with strings under tension like that but will if you shellac it for increased strength and rigidity. Canvas can be stretched and shellaced without the acrylic medium. I'll let you know how it performs when the shellac arrives.