Old bed sheet
 

Just learning free motion quilting and I had a old white cotton bed sheet that I made my quilt sandwiches with. I noticed the bobbin thread pulling to the top. I lowered the top tension until it was as low as it would go and still the bobbin thread came up. I was talking to my mom and she said she had heard that you shouldn't use bed sheets because the weave was to tight and that might be why I was having problems. Does anyone know if this is true about bed sheets? I had bought it at an estate sale to try with free motion quilting so I wouldn't waste my fabric.

Yes, I know several longarmers who won't use sheets because they end up having tension issues just like you.

For practice, get some muslin. It's very inexpensive.

The weave is tight on the very high end high thread count Egyptian cotton, is your bed sheet cotton or percale? Percale tends to be a pollycotton mix which could be tight. I have used pure cotton bed sheets as backing and no problems with FMQ on either my tatty old Janome or my Juki.

Try tightening the bobbin thread, and then maybe you might have to tighten the top thread again too. It shouldn't need to be that loose.

have used sheets for backings many times...that old bed sheet may have been a tighter weave than most now a days but we have never had issues with sheets and our long arm...we have used them almost 20 years

Do what Marley46 says. It seems like your bobbin thread tension is too loose.

I use old bed sheets as foundation for crazy quilts and I don't have any tension problems. Batiks are also very tightly woven and I don't have trouble with those either...? Are you on a long arm? I know those use much thicker needles - I've only sewn on a domestic machine so maybe that's the difference?