Originally Posted by nanna-up-north

Yes, I have..... so I have a few suggestions. First, you MUST wash the fabric. Like most everyone has said, muslin does shrink a lot more than normal quilting fabrics. And, I would try the 80- sized needle. The problems you are having most likely are from the processing chemicals on the fabric. When I made my quilt I bought a bolt of muslin from my LQS because I didn't want to run out in the middle of the project. I think this queen sized quilt used about 35 yards of fabric. The muslin I used was 44" wide.

Sometimes I'm so anxious to start a particular quilt that I skip the pre-steps like prewashing and pressing. I ALWAYS regret it. Be patient and you'll be more pleased with the results. Good Luck. I'm anxious to see your creation.