So is the spray primarily for UV protection? Or is there some added durability?
I'd like to know more about Clearshield staying sticky. I never heard that before and it is the brand I was thinking of using.
UV protection and durability. A properly coated canvas can take a serious beating including gentle scrapes from sharp objects and wiping with wet cloth.
Never had any problems with Clearshield staying sticky, although I have not used it on anything recently except Epson Premium Matte. Two fairly generous coats 24 hours apart, as with many paints if you apply a second coat too soon that can inhibit the first coat from drying...in the end trying to go too fast makes everything take longer. Good painters must cultivate a degree of patience not common in our times.
Of course it's sticky while it's drying. A double-coat canvas really takes 3 days to completely dry after the final coat, simple fact of life. If you try to wrap it before that then I suppose it will feel sticky.
I wonder if Dan's stretcher machine is pulling too hard?