I'm almost afraid to answer this thread because paint work is so tricky, so many things can go wrong and if it screws up on you I'll feel bad but here goes. Dupont Centari, Wow, I had the whole mixing system in my shop for years but the State of California deemed acrylic enamel a hazard to our health and took it away almost twenty years ago, but that was good paint. If you followed manufacturers instructions and mixed the paint properly, some painters use less than recommended amounts of hardener, some more, and you reduced the paint properly, and the temperature of your shop, booth, or garage was warm enough to dry the paint all the way through, heat lamps are a painters best friend, a couple days are all it takes, more in cold weather. Some added info would make this advice easier, like what color, metalic or solid, what reducer, what hardener, what is the average temperature in your area, did you use a blending agent, did you scuff up the old paint and clean the blending area, are you going to wet sand first before buffing? There are special products to acheive your goal, like Liquid Ebony to use in your final polishing, which I think has been discontinued but most polishing lines have a similar product. I had several blends which just didn't look stealthy absolutely dissapear with the right polishing products the next day, and Liquid Ebony did it almost every time with acrylic enamel and acrylic lacquer. A blending agent applied within seconds of your final coat makes blending so much easier, I use a rattlecan Five Star product for todays urethane clear and it usually does the complete blend, if you can barely notice the blend about twenty minutes later it will be all gone the next morning. I used to use Blend Ez on Centari, bought it in a gallon can and had it ready to spray on quickly in a seperate gun after the last coat of paint, have no idea if it's still in existance. I'm not an expert or paint instructor, just a guy who has made a living reconstructing wrecked cars and trucks for over fourty years. Paint work=atmospheric conditions, chemical reactions, product knowledge, painters talent, and sometimes trail and error or just plain luck.