I have previously revitalized a bike by simply cleaning up the frame and shooting a couple coats of clear enamel over it, and would like to do something similar to this on a bike I've been riding through the winter and want going again ASAP. I didn't take into account drying time with the last bike, and even after letting it sit a month, it was still fairly easy to nick with a fingernail (although, a nice hard finish now that it has sat a year)

Is there a home remedy that allows me to get a decent looking clear coat with less than a month drying time? The clear coat is strictly to keep the paint in a condition it is already in, to stop any rust/corrosion. Ideally, I'd prefer in the week or less range. I have seen two different manners: a) using two part urethane spray (not sure if that'll go over existing decals decently enough or not, and carries hefty health warnings), or b) building a drying chamber and using the enamel (no real consensus on temp/time). Has anyone tried either of these, or have a third alternative I am missing? If I'm asking for something unrealistic, let me know that too.