I love spray basting. I use 505. I let it sit overnight so it dries well before stitching. It does not gum up my needle or machine. I have a large roll of wide craft paper of which I cut looooong pieces off and place slightly under and around the quilt to catch the inevitable overspray. Can't do it when DH is home, he'd have a FIT. I do it in the living room. It washes out of the quilt and leave no residue. BTW, I think 505 is acid free, but not sure.