This did not do what I expected it to do after reading reviews and I even called Corroseal. I asked them if this would turn my truck bed a solid black color and was told that it would. Well, it doesn't. If you read the website and the bottle, it says that areas that don't have rust will have a clear coat and that's what it does. Just don't think you're going to get a nice, even black primer coat. If your entire surface is covered with rust, then you will. If not, only the rust will turn black.Once you know this, and that your brush strokes won't show - which I was initially worried about - then you can just slop the stuff on more quickly. What this is, is a clear coating - that happens to also turn rust black, and seals it in a clear coat.That said, my main purpose for using this was to kill the rust in my pickup truck bed and seal and protect it from further rust damage. I live at the coast, and the rust was winning thanks to the salty air here. I lightly sanded the entire bed of my compact 93 Nissan pickup - the inside walls and the bottom. Then I scrubbed it with water only to get rid of dirt that had accumulated around screws, etc., then I ran it through a local car wash, as I don't have access to a hose at my apartment complex. The car wash also helped dry it. I chose an option with water and soap only.The next day after the sun came out and the truck bed was completely dry, it was about 60 degrees. I only needed one quart for my job. I bought two separate quart bottles, in case I wouldn't need them both. I'm glad I did it that way. Amazon let me return the second bottle.My advice - you will wonder if you're putting it on thick enough. I think I overdid it, but I did get really good coverage. Only the rusted spots turned black and you will see those areas turning black pretty quickly - within just a few minutes. So, if it's not turning black, it will just leave a clear coat there. So, don't think the problem is that you need to put more Corroseal on it, to get it to turn black. You just need good coverage - not multiple coats. When I went out the next morning, the black areas had grown and gotten darker. So, it will continue to "cure" overnight.I did end up with some areas that show whitish drip lines around the inside walls of the bed. I think this happened because I kept putting more coats on that weren't necessary, and perhaps it had dried to much? It's still coated, and if you were planning to paint it, it wouldn't matter. It still looks overall so much better than it did before, I'll get over the very minimal drip lines, that probably nobody else would ever notice or care about anyway. The coating darkened up the paint and it looks so much better. The paint was really faded in my pickup bed, and with the coating on it, it's a much deeper color and shiny.If you drip some onto your bumper, it will show the next day as a shiny spot - it's like Varathane. So, you might want to pay attention and wipe up any drips or spots. Still, the overall change in my truck is amazing. The bed is spotted with black and red (truck color), but it looks a deeper color and shiny, and no longer looks rusty at all.I also put some on my chrome wheels that had a few rust spots and it looks good. There was also a rusty spot on the front bumper where the previous owner scraped it, and I applied some there, and it turned it black, so now matches the bumper better. At any rate, for about $30 total, with a 3" roller (which made the job easy) some sponge brushes, etc., my truck looks eons better, and is now protected from further rust damage.I did take some photos and will see if I can upload them later.Edit: I added photos. They are the truck before any prep, the bed half-way coated - note where you can see some black but the rest is just a clear coat, a close-up of the bed where you can see areas where it turned black but the rest is a clear coat, the bumper after treated which used to be rust-colored and the final after photo of the truck. Although not the even black finish I'd hoped for, it still looks a million times better.