Looks to me like the last coat of paint attacked the previous.
Using rattle cans, in some cases, actually requires more care than using an airbrush IMO. First, the pigments in a spray can product are not as fine as in a model paint product. Second the spray can is far less controllable- it is ON or OFF - no in between, which often leads to too much paint for a scale model or runs, or the crazing you got.
It looks like the solvent in the most recent coat is attacking the underlying coat. It can be as a result of too heavy a coat on the last one- or of the underlying coat not being dry enough before overcoating. You should probably either remove the paint using a series of solvents- like Denatured alcohol, then (if that didn't work) mineral spirits, then finally lacquer thinner.
Good results are possible with rattle cans. SO you don't have to have an airbrush. To get better results-
1. I assume you did not use a primer?? (If so, it is possible that the primer (especially of a different brand of type than the top coat paint) is getting attacked by the color coat. Use the same brand and type of primer as the color coat. BUT using a primer often covers fine details like rivets etc.
2. If you use the center of the spray pattern and/or too close- that part will be too heavy, and above and below too light. (You cannot spray it TOO light, assuming you are not 2 feet away. ) Apply just mist coats, using 3 or 4 coats for the job with drying time between. I start off ahead of the object and pretty far away- maybe 12", actually painting BELOW it, and use the outer edges of the spray pattern to actually paint the train. Then move up a little when going the other direction. Move the can rapidly to avoid runs. Maybe make three passes to try and mist the whole thing. Practice on a piece of cardboard.
2. Start OFF the object to one side, with the nozzle 12-15" away, starting to paint with the center of the spray pattern below the object.
3. Move the can in one direction from off of one end, until the nozzle is beyond the other end. Repeat going the other direction, moving the spray pattern about halfway up, then a final pass in the original direction. Then let it dry 5 minutes or so. Wait for 5 minutes or so between coats but not over 24 hours.
Happy Sunday Folks, Thought I'd highlight motorcycles today. I learned how to ride a motorcycle at age 12, on a dirt track know back then as "Scramblers" My Brother in Law, was a racer, and Harley shop owner. I rode up until a few years ago, but stopped due to the psychos on the road.. Any way, I've always loved the english bikes. Not too many in O scale. But here's a few from Germany, by "Schuco Piccolo". Pricy, but worth it as you will see.
