I've got melted milk chocolate on wax paper on a cookie sheet in the fridge. Using it to hopefully cut out decor with cookie cutters.. *crossing my fingers* it works.
How long should it take for the chocolate to harden for this?
your post shows 12:50 it is now 1:17, check now.... it should be done depending on the thickness!
Properly tempered chocolate should be set within a few minutes. If not, it wasn't tempered properly. You don't want it to be in the fridge for longer than six minutes or the moisture will damage it.