I recently finished pieceing a queen size quilt top. I was so excited to start quilting it that I forgot to prewash the fannel backing that I'm going to use and I've already cut all the fabric in 12 1/2 inch squares. I know it's going to shrink and ruin all my hard work I did on the top. Is it to late to wash the flannel? Will my squares fray much. Should I go ahead and piece the backing together and then wash? What should I do? Any remedy for my blunder?

even if you could wash it in a bag and it didn't fray, flannel shrinks a LOT and your blocks will be too small
kathy

If it didn't cost much, sew the blocks together, run overcast stitching around the edges, toss it into a bag and wash it. Use it later to back a different project. (or 4 baby quilts.)

Or, if you can't get more of it, overcast each block, bag 'em, wash 'em, then add borders to make them the right size. You'll have a more interesting back.

No one says you can't have a border on the back; get a print flannel in matching color :)

Debbie,
I'd buy new flannel for this project and prewash it. Then use the flannel that you've already cut for another project. Prewash it in a lingerie bag. My sister uses the lingerie bag for her small fabric pieces and she reports that it cuts way down on the fraying.

If new flannel isn't an option then follow Ruth's suggestion and add a border. But do prewash before using it. Flannel is notorious for shrinking a lot.

I'm so glad I read this post. I bought some flannel yesterday to use in making placemats. I usually wash my fabric but for some reason hadn't considered washing this. Ill definitely wash it before I cut it. Thanks again...you all saved my project.

I used to wash all of my fabrics in the "regular cycle" and had lots of tangles regardless of clipping the corners. Then I thought about how I was going to launder a quilt once finished: the "gentle cycle". So, from then on, I only launder my quilting fabrics on the gentle cycle in cold water, med/hot dryer and removed before completely dry. I also found that the fraying was minimal and I don't clip corners or serge the edges.

Suzanne