How long does it take for paint to harden completely?

I have painted a bicycle of mine, yet the coat of paint is still not as hard as it should be. I dropped something on it and it scratched. It's no problem, because I have more paint to cover up the chips, but how long will it be before the paint hardens completely and becomes more robust? It's not spray paint, it is the sort that comes in a can and it is supposed to be tough, durable paint that is designed for railings and such.How long does it take for paint to harden completely?
A lot of it has to do with how you prepared the surface. If you simply sanded down the old paint and applied new stuff you might have compatability problems and it may never harden completely. If it is enamel (this is common stuff sold for railings and household use) it will take at least 30 days assuming the preparation was completed well. If it is lacquer and the surface was prepared well it should take about 10 days.





Paint is almost fully cured when you can no longer smell it when you get up close. The smell is the solvents evaporating. After you can no longer smell it, allow 2-3 more days for a full cure.How long does it take for paint to harden completely?
this is the very problem with home done paint jobs. the adhesion isnt good. i think you'll find that it is dry, it just isnt durable. there is a huge difference between what a paint shop does and what you can achieve at home. i suspect no matter how long you let it dry, it will continue to be easily chipped and scratched. i dont believe it is a matter of curing, it is a matter of the quality of finish you can achieve at home.
Firstly, how many coats. Next, what colour. Matt or gloss. Brush or spray? Then you start getting technical.





However, I would allow about a day. If you did silver or similar, then you are probably looking at a long time.





Most commercial concerns will dry their paint in an oven. This speeds up the process. However, you might find that the paint will dry faster in a warm, dry place, than left outside.





You might also increase the toughness of the paint by applying a coat or two of lacquer over the top.





Luck
You don't say how long ago you painted your bicycle, so this answer is hard to answer. If you did it yesterday the paint isn't set yet give it more time. If you painted it a week ago either it's no the right paint for the job, or you didn't prepare the surface properly before painting.
This is what you get when you paint bikes yourself. Unless you have proper facilities for painting it is not a good idea.
normal house paint is touch dry in 4 hours, but not hard dry for around 12. Hard paint takes a good four days, a week to be sure, for it to go solid
Can take days to harden off properly - depending on how thick each coat was.
Usually 24 hours but it will depend on how thick the paint coat is
Enamel paint takes at least a week to fully cure.
depends on how many coat's and what kind of paint.