I never used to prewash. However, I prewashed all the fabric used in my last quilt (cotton). And I washed the batting (Cotton with scrim). All items were washed in warm water and dried in a dryer on medium setting,.It was long arm quilted with poly thread. The finished quilt measured 65 x 117 inches. I washed the finished quilt and it shrunk, 5 inches in width and 7 inches in length. I thought prewashing would have eliminated shrinkage of the finished item. Has anyone else had this happen?

I prewash due to allergies and wanting to know if something will bleed. I mostly work with batiks and they tend to have excess dye that is eliminated by prewashing. That said, I don't wash precuts when I work with them.

I have never understood only washing big pieces of fabric and not washing little pieces of fabric.

If there is a problem with a big piece of fabric, wouldn't a little piece of the same fabric have the same problem(s)?

Yes, I imagine the little pieces would have the same problems -- that's why I don't buy pre-cuts, etc.

I only wash the vintage sheets I get from the thrift store, not new fabric. And is use them together with no problems (bleeding, shrinkage, etc.) The batting and quilting usually control the degree of shrinkage. I typically lose about 3%, which is what the labels tell you to expect.

Some of us pre-wash for a variety of good reasons. I am one of them - allergies.

Prewash or not.
 

I always wash reds after turning a beautiful Christmas table runner pink yrs ago. I prewash some fabrics if I question the quality. Some, once the sizing washes out, is so poor I won't use it for anything.

Chem, I don't prewash MOST things, BUT, eventually it will happen. One piece of fabric will leak dye and then you will get mad and go back to prewashing for awhile anyway. I only buy quiltshop fabric, but for awhile there, I had dye leakage from RJ Fabrics. Doesn't happen any more though. I still have dye leakage from dark flannels, so if you are going to mix it with light colors, I recommend prewashing the dark to get the excess dye out (and there will be a lot of it if it is dye leaky). I had a valentine's quilt turn blotchy red with Joann's flannel fabric on the back. It's muted now so doesn't irk me so much, but just a warning - you never know when it will happen. If it's an important quilt, I'd prewash.

FWIW, I prewashed all my fabric for the first 10 years and then got lazy. I know which fabrics aren't prewashed (Asian, Halloween, panels, christmas glitter, flannel), so it's not a problem for me, but whichever way you go, make sure you have a means to know whether it is washed or not washed. I prewash all backing fabrics because I've had them shrink as much as 7 inches over the length of a queen sized quilt which would have caused some problems.

I used to be diligent and washed everything. Then I got lazy and didn't BUT I made sure that ALL fabric in the quilt was either washed or not. By now, I have no idea what was washed and what wasn't. I use it as is and wash the quilt with color catchers.

One thing I NEVER prewash is precuts. One fabric I tend to still wash is batiks.

As for the crinkled look - I still get that even with prewashed fabric. It's all fun and games and fortunately, I am not allergic to chemicals. Now show me a blooming tree and I'm a snarling mess.

I did not prewash my fabrics for years, then I started working with flannels which shrink in crazy ways. I also normally wash batiks, but I have a large stash and not all of it is washed. I just started a scrappy project and thought I had prewashed the scraps. Well, I starched a piece of red and it turned the ironing board cover red so I started testing the fabrics by wetting them, putting them on a paper towel with a glass of water on top and wound up throwing all the pieces in the wash. One of the batiks started leeching color before I put it on the paper towel and another turned my fingers pink. Most of the problems were batik, but a couple of blues that were Moda fabrics bled as well. I have found that if I want to be lazy and not prewash, I need to test the fabric first.