I have used flat sheets for the back of quilts, with no problem at all..there are a couple charities i know that use the flat sheets from walmarts..it is one of the few places that sells them seperatly.
you can pick up christmas flannel sheets cheap now..i have used them on the backs of Christmas quilts..
i am not a purist, and no quilt police are allowed in my home..:) my quilts are not junk either..I also do alot of charity quilting..

I made a customer a quilt entirely from sheets. She had it professionally quilted and then brought it back to me to put the binding on.

Sheets fray terribly!

OHHH AHHHH I see 70's sheets! Very pretty!

I have done it, to make a quilt for my mother. She wanted a quilt the wrose way, but she lives in Puerto Rico. She didn't need it for warmth, ut for decoration. Making it with the top and the back alone showed the seams on the back, so I added a very old well washed sheet in the middle. white, so the color wouldn't show and old so it wouldn't shrink. It worked out great. She always have it on her bed and uses it to cover herself when the temperatures in the winter reach those harsh winter levels of 70 degrees at night. Don't I wish those temps right now.

Maria

I have about six of my late mother-in-laws quilts that were made in the late thirties or forties which were made from scrapes.They had old sheets and a heavy backing of muslin. They weigh a ton each. When you are under one you feel like you have been tucked in for the night. They had no pattern to them just scraps of all shapes that were available. Definitely for warmth not looks.

I got an advertisement from American Patchwork & Quilting today and they had a little blurb in there that you shouldn't use sheets for your backing. The thread count is high so the sewing machine needle actually tears the threads instead of separate them. This causes the fabric to fray, weakening the quilt. I guess it wouldn't matter if you used the sheet as batting.

It is for the middle. I am making a baby quilt now that she is helping me with. We are using a cotton sheet for the middle and so far so good.

The problem I have heard about is that the high thread count makes it difficult to hand quilt, so wasn't aware the thread is torn by the needle.

My question, then, is why use that high a thread count, even for sheets? Won't the hems weaken considerably, and tear?
(yes, we use sheets on the bed - but mine are about 30 years old, and contain polyester... we still are using the wedding presents...)

you use them on the bed because the high thread count keeps them from wearing out. the seams are on the edges, where they don't get too much wear. if you look at the seams closely, you can see that the needle has actually punctured the fabric to get through. a blend is much better to use for quilts if you make sure that all cottons have been prewashed and dried.

there used to be a thread (hehe) on this, but i don't see it anymore.

Thanks, butterflywing, for the answer.