Intake vent with light trap

**fdd2blk** · 05-11-2008, 04:23 PM

anyone got any ideas for me? i need to put one in the lower left corner of this sheet rocked wall. it needs to go on the outside. IMG_6808.jpg IMG_6809.jpg

**fdd2blk** · 05-11-2008, 06:34 PM

i'll take it that's a NO?

i'll figure something out.

**fdd2blk** · 05-11-2008, 07:53 PM

"I stumped the forum."

**Red Eye Jim** · 05-11-2008, 10:18 PM

I was told that you can purchase a light filter from a darkroom photography supply store that lets air through but blocks light. Is this what you were looking for?

**fdd2blk** · 05-11-2008, 11:19 PM

Originally Posted by Red Eye Jim

I was told that you can purchase a light filter from a darkroom photography supply store that lets air through but blocks light. Is this what you were looking for?

yes, this is what i'm looking for. i'll google that. thank you.

**fdd2blk** · 05-11-2008, 11:29 PM

this is interesting.........

(this is for darkrooms but it's basically the same)

Terry XXXXXXX , Sep 01, 2000; 08:20 a.m.
The easy answer is to buy a darkroom fan and darkroom vents. These are manufactured devices that are light proof and have a fan or not.

I would be careful venting into a crawl space. I would run a duct from the exhaust to the outside.

For 880 cf, you want a fan of between 88 and 220 cfm. That will give you between 6 and 15 air changes per hour. Remember to take into account that ducting will reduce the air flow of the fan due to backpressure (technically static pressure losses).

The best setup for a darkroom is a combination of positive and negative pressure ventilation. You blow filtered air into the darkroom and you power exhaust air at the same time. You size the fans such that you blow in slightly more air than the draw out. This way any leaks leak air out of the darkroom, rather than in carrying dust.

THe best place to exhaust is over the sink. This way the chemical vapors and dusts are removed closest to the source. The absolute best way is via a slot hood. This is an opening about 1-2 inches high the width of the sink. This is the exhaust port. You then size the exhaust fan to suck about 200-400 cfm throught the slot. Antyhing from the sink rises slightly and then back and out the exhaust. I built this for my sink and it works great.

BTW my background includes industrial ventilation design for contaminant control. So I am giving you advice to make a GREAT setup. The other posts will work, maybe not as well, but they will work. The big thing is to exhaust near the source and get enough airflow.

**fdd2blk** · 05-11-2008, 11:47 PM

well i'm not the only one. i google "light proof vent" and i get 100 grow sites. everyone asking the same question i am. no positive answers. a bunch of Mc Gyver stuff but that's it.

**shamegame** · 05-11-2008, 11:56 PM

You can get baffles from some hydro shops that fit over the end of the exhaust and don't let much light in. Also people take black fabric or like panty hose and stretch it over the exhaust, sometimes do this reduntantly to make sure no light gets in.

**fdd2blk** · 05-11-2008, 11:59 PM

Originally Posted by shamegame

You can get baffles from some hydro shops that fit over the end of the exhaust and don't let much light in. Also people take black fabric or like panty hose and stretch it over the exhaust, sometimes do this reduntantly to make sure no light gets in.

now that you mention it, i need to cover my exhaust as well.

**W33D** · 05-12-2008, 12:17 AM

Hook some black tubing up long enough so light doesn't show through. Have it sealed on the inside part of the intake vent, and run the tubing along the bottom of the room, giving it "corners" if necessary to block light and allowing fresh air underneath the canopy. This is one method that came up in a brainstorm. Another was making block sort of thing like steps inside so light doesnt bounce off the "/\/\/\" and get through the other side. Get it?