Rattle can?? like rustoleum rattle can spray?? I wouldn't use that but is your call. No idea about the dry, the issue with rattle can is that can be dry outside but inside u never know. The way the paint dries is the problem, it use air to dry, car paint is dried chemically, so u can get the paint hard and ready after 3 hours. So maybe it will work fine for a bench but for a bike is a risk because some parts dried right, other ones after months are still fresh to the touch u know.

Good luck