I had some leftover blocks from a quilt, so I sprayed the back of one and put another on top. Left them dry a day, put 4 safety pins in, and tossed it in the wash. Was surprised, there was no difference. The 505 was still there, the blocks were secure. I did peel them apart after removing pins, and with an iron, rebasted them. I was surprised None of the spray washed out. Not sure how I feel about that, but for the price, may try the washable elmers glue next time. Love using it on bindings.