For what its worth, buy a finished product.

To DIY a box of sorts, isn't worth it. Probably gonna cost $20 min, then probably a tool or two, other hardware to mount a drill bit or two, etc. Plus what your time worth? If it takes you 3 hours to do it (research time included) That, at $20 and hour, is $60. And if you are doing this after work, consider it overtime, so $90.
So labor $90
Parts $30 (parts $20, extras $10)
Total $120.

Covers the extra expense of a pre-assembled unit.

Now that being said.....

I have a pair of 150W ballasts sitting on an aluminum plate. On the Plate between them is a heat sink form a 200A servo drive in free air. (but a stable location)

I liked the mailbox idea! (though I wouldn't use it for this prioject seems big)

I'm thinking
small toolbox?
File/index card box (staples, office max)
Micro computer case?
Gutted A/V component / small appliance?

ghetto -
rain ducting (down spout)
Large can (restaurant supply)

__________________
The Temporary Relief Assistant Trailer Park Supervisor. Carmelisous Jornl :: ElecUsageCostsCalc

__________________
Our Beautiful Ladies ...
Keep Them Safe
Keep Them SECRET!

How about an ammo box from an army surplus store. Bet that would be perfect to house your ballast. If you enjoy doing the work like I do then it a bonus to go DIY,not a cost that needs to be figured in. I built a cabinet and it probably cost me more than a kit, but it is perfect (after a few major revisions) and looks nice and is very very stealthy. I am a very anal woodworker, so it had to be perfect but I respect any grow box (ghetto box included) that is hand made and produces some bud.

why in the world would you go to all that trouble to save a few dollars and end up with something probably rigged together and only 250 w. All the time and effort and money and if it doesn't work perfectly youll spend far more on it then going on ebay and getting a new light with ballast and everything that works as it should.

Ballast Box - for all wattages | Grow Light Ballast Assemblies


Electronic Ballast Boxes, Transformer Cans

__________________
D3RANG3D

I dig the first one. Second one looks enclosed. I prefer to have a little ventilation or cooling fins.

__________________
The Temporary Relief Assistant Trailer Park Supervisor. Carmelisous Jornl :: ElecUsageCostsCalc