I found a wonderful old "happy" flannel sheet that I'd like to use to make 3 rag quilts. All of the other flannels for the quilt are
brand new.

Should I was the new flannels a few times to shrink them first before starting the quilt? If so, should I put them in a pillowcase so that they don't tangle?

Everything's going to work out fine - right??????

yes i would wash the new flannel so there would not be undue shrinkage.

Most people will tell you to NOT wash the flannel before using it for a rag quilt, but I had already washed mine before I decided to use it for that project. Everything came out just fine and it still "ragged" nicely.

Are you using the old flannel in the middle of the blocks or is it going to be on the outside. If it is going to be in the middle there is no need to wash the the new first. If it is going to be on the outside I would wash the new. Also, just a tip I learned after making about 20 rag quilts the closer you clip the nicer the ragging looks.

I have made several flannel rag quilts and I always wash the fabric first as some of it shrinks more than others

I always wash mine first.. flannels can shrink so differently....

of course it will work out fine!!!! That's the way u designed it!... the beauty of handmade!

I always wash my flannels - two or three times because they shrink a lot.

This is so true! It will rag fine after it is washed, and flannel often bleeds a lot in the first washing (or two or three) - another reason to wash it first.

I have never washed fabric, but I heard you should never wash it.

I heard both, but started washing because I don't want to spend all that time and money on something to give as a gift, then have the recipient wash it and it shrink and fall apart. That would be totally embarrassing!