I have used sheets for backing many times..it eliminates that seam in the back that you have to do for larger quilts..I always take a look when in a thrift store to see what sheets they have. and often find good ones there..for $2-3 most of the time......there won't be shrinking with these used ones........just look at them really good before you buy one, to be sure it isnt faded or has any holes............