When I made my boxes of strings (see the tute on this site) I used a very light fusible interfacing. Many of my strings were only 3/4 of an inch wide so I was sewing a 1/8 inch seam. The fusible helped make sure that my seams were not going to fray out. But I have made other string blocks using no foundation. I have also used old tissue paper patterns cut to specific sized squares and shortened my stitch to 1.5. The paper tore off very easily. Since the blocks I was making were diagonal so it was nice to have the extra stability.
And precuts like jelly rolls are a lot wider than 3/4 inch. Same with a lot of the precut squares. I think it is all about the size of the fabric being sewn together.
Last edited by GingerK; 02-10-2019 at 05:47 PM.