Dean, Chrysler has been using S-W waterbourne on their Jeep products for the last 4 years. GM has certified S-W for waranty repaint and collision refinishing of it's vehicles. Any paint company that wants this certification has to subject their product to a rock chip test. That test is esentially dropping a plate of small rocks into a small wind tunnel that directs the rocks at a painted panel. Wind velocity is 60 MPH. For the paint o pass it can have no more than six small chips. S-W has ureflex in it's premium basecoats and clears allowing them to flex not chip. I would question the prep of the bumper not the product. If you have any questions about the product you can contact Clint Baker at the Reno training center. His email is
Clint.J.Baker@Sherwin.com
Don