I have used it on a couple different projects when it first came out.....floor pans/underside of my demon(brushed on), sprayed through a primer gun (followed instructions) on a chassis and firewall for a Nova project. Stuff came off in sheets on the Nova....and yes instructions were followed and they were called and said it shouldn't be a problem. It wasn't. On my Demon it stuck to the surface rust good, but didn't adhere elsewhere very well. It was brushed on over the factory painted floor pan. I have since blasted the entire car and used Glasurit epoxy primer instead. The POR15 stuff is rock-hard when it sticks though and IMHO looks like it was brushed on so it shudnt be used on a visible surface.