Fan position and direction

My box is getting a little hot. Ive got one computer fan and a 12v transformer. Where would be the best place to put this? Note, i would like to keep light leaking at a minimum. I was thinking, putting it above the light, and having it blow air outwards (facing up). But it gets awful hot in there, so maybe that wont do the trick?. I could put it on the side blowing out, but more light would probably escape that way.

Any help?

Don't know how powerful the fan is, but you shouldn't worry too much about light leaking out. You want to worry more about light getting in - especially during flowering. Hot air rises, so the top might evacuate more of it, but if the fan is strong enough, it won't matter too much. Just make sure fresh air can get in. Intake lower to the ground and exhaust higher toward the top.

Ok. Ive got two computer fans (one is standard size, other is a little bit bigger, its from a power supply), a power supply, a power drill and my grow box in front of me. I'm pretty sure that i will have one fan as an intake, one as an exhaust. This grow box is very small, and will be used primarily as a home for my clones that are taken from an outdoor plant. But first, i will sprout 3 seeds inside it, to be taken to plant outside.

So my question is, how should i place the fans?. Space is a real problem, my light is a CFL, positioned right in the middle pointing upwards. Without any fans it gets very hot inside (way over 100f). My current solution is having the fans on the top, within about one fans distance from eachother. One intaking, one outaking. There is about room for 3 computer fans along the top, so the one fan distance is the best i can do.

So will this work and keep the grow area cool? and what about light leaking? How can i minimise this?

Cheers.

Do you know how many CFM your fans are?

The smaller one pushes 29cfm and the larger one is 32.9cfm

you may want to consider using both as exhaust and just putting in a few passive intake holes. If you decide against that, then i'd use the higher rated fan as exhaust and still add an extra passive intake hole with the intake fan.

the exhaust should be near the top and the intake should be near the bottom.

using both fans to exhaust would be adequate for a room 2' x 2.5' x 3' (or 15 cubic feet)

Im just going to use one. Its pretty loud as it is. Ill use the big one, off the box its very quiet but when i screw it on it becomes very loud, as far as i can see it is resonation from the case making the sound. Anybody got any ways of reducing that sound? Plus, how large should my passive intake holes be, and where should i place them?

i heard of a few tricks for reducing fan noise but haven't tried them. mounting the fan using bungie cords or rubber grommets is the most likely thing to work. reducing the amount of duct work also helps reduce noise but i don't think that pertains to your case.

the intake hole should be larger than the exhaust and it is better to have more than one. example: A 6" exhaust fan would benefit from having three 3" holes - multiple holes adding up to a larger size than the exhaust hole.

most growers put their intakes near the floor and the exhaust near the top. this aids fresh air intake by using natural circulation (hot air rises).

I will pick up some thick rubber washers tommorow after work, then ill drill lots of little intake holes (0.5cm). Rather than a few bigger ones. Im trying to keep this box as stealthy as possible. I dont realy need so much stealth, i just wanna see how stealthy i can make this lil clone box. So, im thinking about 20 0.5⌀ cm holes drilled along the bottom of the box. I will try and make a light trap or somthing, so i dont have any gaping light holes out the bottom, i will need to do the same for the top. But im thinking just have a long card section, kinda like this :
Urm. The (==) is the fan (exhaust), and the strip underneath that is the light trap. Will that work and still give adequate ventilation? The light would be underneath that (CFL).

i think two ninety degree bends would be needed trap light.