Kellie,

I don't think it's a good idea for you to mix your quilting cotton with flannel fabric. The shrink factor was mentionedd above and I agree with that. I have some old quilts mades mostly of cotton and here and there a flannel piece was used and the flannel just hasn't held up like the cotton. If you are totally in love with the flannel, why not make an all flannel quilt? I have seen flannel backings on cotton quilts and I guess if you pre-shrunk the flannel first you could give it a try on the back of your quilt. The thing about flannel is that it continues to shrink over several washings and you don't really know where it will stop.