DIY Darkroom Louver

[touchofgrey]

I've been thinking of this idea for a light-proof louver. I liked ScrubNinga's version using aluminum angles but wanted to simplify it a bit by using pieces of off-the-shelf flashing that would be easier to cut. I made a model on Sketchup.
The idea is to make blades from 5/8" Z flashing, the kind used for horizontal joints in plywood siding. Flatten these pieces slightly so the middle is at a 45 degree angle. Sandwich a piece of screen between them and poprivet together.
The blades would look like this. Then make a frame to surround the louvers with a piece of Z metal to match the width with an angle metal attached to form a C channel with a flange.
It would look something like this assembled.

Has anyone tried anything like this? Do you think it would work? Just trying to sort out the fatal flaws before I build one.

 

[ScrubNinja]

Looks like it would work to me. One issue I see is that if you look on the upper face, say in the last pic. Observe how much free space and blocked space there is. I'd say it's roughly 60% blocked. That's the tightest restriction.

If you have skinny stuff in a Z shape as shown, then why not use it sort of like this:

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You would have a very minimal flow blockage then. In reality it would look more like:

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[messn'n'gommin']

It wouldn't cost much to do, maybe $20 - $40, I say go for it!

 

[touchofgrey]

Back with round 2 of the design. Scrub was right, there was wasted space and with micros we need to be very efficient! I decided to get rid of the separate frame and simply extend the flange created by the sandwich concept to all 4 sides to create a mounting flange. I also changed the bottom louver to just a wide flange to eliminate wasted space.

an x-ray vision view and the exploded view


This is using 1" Z metal (flattened to 135 degrees) for the louver blades and 3/4" Z metal for the end caps. Have to pick some up next time I'm at the depot to make a mockup.

the math on this design is as follows:

cutout size: 8" x 20" - 160 in2
free area: 4 slots - 3/4" x 18" = 54 in2

In know 33% free area isn't that great for an air louver but I think it might not be too bad for a lightproof louver.

 

[ScrubNinja]

Cool bro. Is it easily dismantle-able? I'm just thinking that screen seems like it'd catch lint and whatnot after time, seems extraneous.

 

[touchofgrey]

Is it easily dismantle-able? I'm just thinking that screen seems like it'd catch lint and whatnot after time, seems extraneous.

It wouldn't disassemble easily since I was envisioning putting it together with poprivets. I put the screen in as an insect screen but it is a non-essential element and does restrict air movement to a degree. Could definately leave it out.

Actually, I've got insect screen on my intakes now and I still get fungus gnats. Maybe they're small enough to go through regular insect screen. How do they get in there anyway?

 

[ScrubNinja]

My guess is they'd come in via a medium like dirt, coco etc. I think mine came from jiffy pellets originally. I reckon a determined small gnat could get through insect mesh too... maybe.

I ended up switching from dirt to coco and that let me use h2o2 without issues. Got rid of them instantly. If you're in a non organic situation like hydro, don't even hesitate to use it, they hate the stuff.

 

[FreezerBoy]

Don't forget the front door. All it takes is one pregnant female to populate a cab. My Rockwool grows were always full of gnats while my DWC has been gnat free (no moist surface medium for nesting) Diatomaceous earth over the top of soil, rockwool, coco is another way to choke them off.

You still want to filter intakes to keep dust off the lamp but, I'd want the material to be as easy as possible to replace.

 

[touchofgrey]

Scrub & FB, thanks for the ideas.

I was originally thinking the screen would also be something to help give it structure during assembly. But the way it has evolved here the louvers and end caps will be plenty of structure. It can be made up as 2 separate sides, put a replacable filter media in the middle and screw 'em together. That way it would be simple to open and clean or replace the filter.