you assert that a number like 8 is the number of hours? since when?
8 is a timespan, not a date. If youre after a quick and nasty way to turn 8 into a time:
DateTime.Date.AddHours(8).ToShortTimeString()
This takes todays date at midnight, adds 8 hours, and pulls the time as a string. Dont even try to compare it to another date.. For example 9 yesterday is actually before 8 today..