I believe Rustoleum and other oil based enamel finishes dry through two processes. The first is through evaporation of solvents added to improve the sprayability/brushability of the paint. This happens fairly rapidly and is over when the paint is "dry to the touch". The second process is the polymerization of the drying oils in the paint. This takes a while especially if it's cold. Several days at least for Rustoleum. If you're dealing with rattle cans, you're pretty much stuck with the paint as it is. If you're spraying canned paint from a spray gun you can add Japan dryer to it which catalyzes the polymerization of the oils resulting in faster drying. In either case, the chemical reaction of the drying oil can be accelerated by heating the parts. As generality, the rate of chemical reactions roughly doubles for every 18 degrees F you heat them. So a little heat can really make a difference. I regularly bake parts in an oven in my shop. If you want to do this you should wait 'til the solvents have evaporated to reduce the likelihood of creating an explosion. Doing them in the dryer as you've shown does have some risk of permanently making the dryer smell like a diesel fueling station so that's some thing to watch for. I've had good luck in the past before I got an oven using a cardboard box and a very old, low power hair dryer. The modern 1200 watt ones may be too much. I suppose a small light bulb or incandescent drop light might work OK. I cannot recommend any of the above as unattended activities. You should be around while things are being heated. It will still take a while before the paint is fully hard. Good luck!
