I am not a paint expert, but my understanding is the best way to make paint be hard is to leave it alone to dry for a long time (a week, or even 6 months - judging from the soft paint on new 1:1 cars)
The other thing is too late for the project you have already done (although you might have already done this) - but is:
make sure the car has no grease or dirt on to start with, and is lightly keyed (sanded)
the right undercoat/primer for the material you are painting and the paint you will be using
lots of thin coats with lots of drying time in between, and possibly sanding between coats
long time to dry before lacquer
let the lacquer cure for a long time too.
This is pretty much a list of what I never do because I am far too impatient!
The other thing is too late for the project you have already done (although you might have already done this) - but is:
make sure the car has no grease or dirt on to start with, and is lightly keyed (sanded)
the right undercoat/primer for the material you are painting and the paint you will be using
lots of thin coats with lots of drying time in between, and possibly sanding between coats
long time to dry before lacquer
let the lacquer cure for a long time too.
This is pretty much a list of what I never do because I am far too impatient!
