Did you remember to leave a breather hole?
While it looks freaking awesome, I wouldn't recommend anyone do this to a drive they want to actually use for storing data for a number of reasons:
The breather hole is a requirement. When a hard drive's temperature changes, the air expands and contracts. This changes the pressure on the actuator arm, changing the distance between the platters and the read/write heads. This can be overcome by making a small hole in the casing and covering it with a piece of insulation tape. The tape has enough elasticity to move enough to counteract the changes in pressure, while keeping the drive airtight to avoid dust contamination of the internals.
On the topic of dust, it is a BIG BIG problem. During the manufacturing process, all of the air in a hard drive is removed and replaced with an inert gas. The average room's air has several BILLION dust particles per cubic meter of air, even the cleanest-of-clean clean rooms have dozens of particles per cubic meter. Just because you can't see the dust doesn't mean it's not there - a particle of cigarette smoke is enough to cause irreversible damage. You may find that the drive begins to develop bad sectors or fail completely within a few hours to a few weeks of being opened. One thing you can do to eliminate some of the dust is to steam out the room you're working in. For example, do it in the bathroom and leave all hot taps running for ten minutes, wait for the steam to settle and then work quickly. Note that this will not remove ALL dust particles.
Light, believe it or not, is also a problem for hard drives - at least long exposure to light. Even the two years of R&D Western Digital put into the windowed Raptor X wasn't enough - the drives still had half the MTBF of 600,000 hours vs the 1.2 million hours of the non-windowed drives.
No matter how careful you are or how many precautions you take, the drive WILL fail sooner.
