Immersing something in a cold liquid will chill it much faster than a cold(er) freezer where it is only chilled by a cold gas. It\'s true that the freezer will chill it colder, but I suspect you\'ll need to repeatedly coolit as you work on it as it will warm up as you touch it. Therefore, dunking it in ice-water for a minute or two will be much quicker than setting in a freezer for an hour.
You could even stick a salt/ice water mixture in the freezer for even colder temps.