You can actually paint a lot of things with spray bombs in better-than-factory quality. Although, the whole thing's success depends on several crucial points:
1. Paint quality
2. Spray can quality (sprayhead)
3. Painting skills
4. Ambient temperature and humidity
5. Abscence of dust
6. Material and surface preparation
7. Size of workpiece
I spray a lot of things with spray cans, because I do not want to make the whole buildup with compressor, spraygun, 2K-paint mixture and so on every time I have to paint a battery tray or a valve cover.
I usually blast the parts in my blasting cabinet. The surfaces are clean and rust-free afterwards and paint adheres perfectly. To get best paint adhesion to the surface, I degrease before painting with brake cleaner pr paint prep.
Depending on the part and its later usage, a layer of primer is applied.
Then three thin layers of spray paint with short drying periods of 10 minutes are applied. The number of layers is directly related to the quality and mixture of the paint. For engine parts, i like the VHT paint bombs, because they are of high quality, have a nice spray head, dry not too fast and not too slow, last long and have good coverage and final shine.
I also use 2K-Paints in spray cans for painting parts that need special durability and resistance, e.g. chassis parts.
Here you can see an ai cleaner housing that was painted in VHT's Ford Corporate Blue. You can also see the blasted surface befor paint.
Michael