Review on Black POR-15 Patch - 4 oz Filler & Seam Sealer with Ultimate Adhesive Properties - Repairs Holes, Cracks in Steel, Wood, and select Plastics - Reinforces Weakened Metal by Roy Boone

(see 2020 update at the end) I bought this on the recommendation of a local auto repair shop. In fact, they recommended I apply POR-15 paint to some of the rust on the roof, but I bought the paint along with this tube of POR-15 patching material for a large area of rust on the underside of the driver's door and rust from a previous accident . on the rear quarter panel of a 2013 Prius. I originally intended to only use this patch on the heaviest rust blistered areas, figuring that sanding and wire brushing would leave some through holes in the metal and a few spots of rust extending into the wheel arch. After prepping with a grinder and wire brush, I applied this patching material to the toughest pitting spots. Then I thought why not use it as a paint and cover all the rusted spots with it? The rust on the underside of the door consisted of paint blisters, three inches above the door along the entire floor, and even sanded off with an electric grinder, there were obvious rust pits. So I used my finger as a brush to apply this patch to the entire driver's door under the crease. The finished repair looks like finger smoothed black grout, but I'm not concerned with the aesthetics, just that the car will last. So I figured if the POR-15 paint is good then the POR-15 sealer should be even better right? I'm not looking for a nice car, just a body that will last up to 200,000 miles out of 90,000. So will the car last that long? I guess not. A friend who taught bodywork at a local school for decades laughed when I told him I was trying to treat rust with sealant. But we'll see and I'll be back. It is thick, viscous and strong, and looks like tar from a pit. Use latex gloves. Update September 2020: Two years and 50,000 miles later, here's what I found out. This stuff works. There have been no recurrences in many areas where rust has formed. Earlier this summer I had to sand and repaint the POR-15 about 20 percent of the area I did two years ago, but I don't blame the POR-15. I believe rust has formed in these spots on the back of the panel from a previous accident. I'm impressed with this stuff two years later.