Intake/Exhaust Fans That Won't Leak Light (For Cabinet)

My buddy is building a new grow cabinet. The ones I've been around have usually been in closets with the door closed so light was never a concern. His new setup is in a room with a lot of light and there is no way to make the room dark. He usually uses large computer fans (well over 100cfm) or a couple of box fans for intake at the bottom of one side and exhaust at the top of the other side. What can he use for intake exhaust in his cabinet thats in a well lit area that will give him the proper air flow he wants but not allow any light leakage during the flowering (or any other) period? The cabinet is going to be either 3x3 and about 5' high or 4x4 with the same height. Thanks.

hmmmm. Bathroom fan. Any fan he can hook up to ducting should work. just bend the duct a little and your good to grow. Good luck

getting an inline duct fan, like a vortex or something like that would work fine. It will give him plenty of cfm to work with, is rather quiet, and can be made light proof with a little modifacation. Either inside the grow area, or outside of it make sure that the duct bends at a 90 degree angle once it exits the fan. This 90 degree bend in the ducting will make sure that the light won't go out, as long as it's long enough. Make sense?

I was in home depot yesterday and was looking at vent covers that are on a hinge....they open when the air is flowing to allow air through and and close when there is no airflow...they were about the same size as a computer fan and made of plastic...very inexpensive....Hope this helps

Remember light travels in straight lines,so if you have a 90 degree angle inthe duct and it's not reflective you are Ok.I doubt if those flap things are light tight when closed.