There was talk not long ago about using 505 basting spray on fabrics other then cotton. Up until recently I had only used it on cotton...Well this last top I have to finish is the one I made from my daughters old scrub tops.Since it was a poly blend, I used the same type fabric for the back and a poly batting.
When I first sprayed it together, it seemed to be fine, but now, about 10 days later, it's no longer holding and I took it back apart. It was only stuck in a few places. So I guess if you use it for fabrics other then cotton, don't spray until you are ready to quilt!!