For any of you who use Jesso for mixed media art projects, you know how expensive the stuff is. This is a new product made from casein resin emulsion; and from what I gather, casein is used to manufacture plastic, so perhaps that helps make it stronger. It hasn't sagged when I've used it to coat small sculptures, and floral shapes (onto canvas) so it's good to go almost immediately with no second coat. Amazing stuff. Plus instead of $60+ it is $12.99 at the hardware store.