I use paper for the backing on my string blocks...plain old "typing" paper. You can use phone book pages. Shorten your stitch slightly - makes the paper easier to remove. Lately, I haven't even been doing that. I love wonky so I've been free-piecing strips...and any other scrap I can find...when the piece is big enough I cut 8.5" & 6.5" Fun to see what you end up with!