I’m painting a computer case with black enamel spray paint (Rust-o-leum brand) and going for a “hot rod” black mirror finish. You can see my inspiration here; that last photo is his reflection in the paint job! I’ve applied primer and a good coat of gloss enamel, and now the instructions recommend two weeks’ curing time before wet-sanding. Other sites recommend two to three days – what a difference! – and then adding more paint, but they still appear to get the glossy finish when they’re done. So what’s the real deal with enamel? Will the extra week of curing time make the finish more chip-/scratch-/bubble-resistant? Does adding extra coats between curing risk blisters or bubbles? Is it (possible/recommended/totally a bad idea) to cure enamel paint in an oven at low temperature? If you can point me to an FAQ about enamel paint, that’d be nice too.
It’s all a function of temperature, relative humidity, and the formulation of the paint. Original Rust-O-Leum took forever and a day to dry, but was quite durable. I’ve used the quick drying “professional” formulation with good success. Repeated coats allow greater film thickness buildup without runs, sags, and checking which can result from too high a rate of application. Sanding is sometimes necessary to give the successive coat some ‘tooth’ and bind to the previous layer. Other paints give you a window of time for successive coats such that the previous coat has set but not fully cured, and the next coat chemically binds without sanding. Enamels produce their gloss via slow curing-laquers are fast drying, but need a final sanding with 600 grit paper and then hand or machine glossing to produce the desired finish. I wouldn’t put any painted object in your oven to promote drying unless you’d like to meet the local fire department personnel.
Rustoleum “protective enamel” has a lot of oils that take extra time to cure compared to many other rattle-can products. The company makes other flavors of paint that are quicker to cure, but less weather resistant.