DIY: A new angle on light proof vents

[DiscoBiscuit]

Oops I forgot. Was gonna get you a pic of Mr. T. smoking on a great big spliff. I forgot that faggot was stooge for the "Just Say No" to drugs campaign in the 80s.

Maybe a joint up his ass? Always looked like a catcher to me. I'll be a little more careful throwin the nicks around. peace

 

[ScrubNinja]

LOL how did we get onto Mr T? Are you high?

I hope so

 

[DiscoBiscuit]

I don't know. I saw Rocky the other night and my brain is boiled ever since.

 

[dank.frank]

Some people are mechanical engineers right outta the mom tube.

HAHAHAHA.....this is almost signature worthy!!!

 

[ItsAllOver]

A freakin great idea. I'll be off to grab some angle tomorrow probably. Rep like a mawfucka.

 

[fatigues]

So I went off to Home Depot today to pick up my materials for my implementation of Scrubninja's DIY darkroom louver.

The angle available at my local Home Depot was available in the molding section, alongside various other aluminum angles and square metal rods.

While plain and even brassy/gold brushed aluminum angle was available in the same size, I purchased the pre-painted black aluminum angle: 3/4" x 3/4" Mira Black aluminum angle #DUA707MBL08 for the main louvers. The material is quite thin ( not sure - I'm guessing 1.2 mm thick - maybe a 1/16th of an inch?). The aluminum angle was not that cheap. I picked up two 8 foot sections of it for about $26.00. These are CDN $ prices, so American ICMag members should end up paying $10 USD less for this material, I suspect. (Prices for most things are just generally cheaper in the USA *sigh*).

The Mira black angle cuts relatively well with a Dremel using Cut-off wheel No. 409. Once you get the flow, you can can cut each piece pretty quickly, cutting through one side more or less completely and just scoring the other - with a bend it breaks cleanly after that.

My main concern now that I have this material home and cut is that the black finish is damn shiny. It has a glossy look under Halogen lights which wasn't so easy to see inside Home Depot. It may well be a little too glossy for our purposes. In fact, it's so glossy, I'm mulling over the idea of just painting it all flat black before assembly.

For "spacer" material, I purchased a thicker aluminum angle, 3/4' x 3/4" Satin Clear DUA3177SCL08. I'd estimate this to be 2.5mm thick - 1/8th of an inch. It's too thin to use just one spacer between the louvers and get adequate airflow , so I'll have to double up on this spacer material.

Problem is, it's too thick to be cut by a Dremel without burning through one cut-off wheel per cut. Right tool for the right job. *sigh* I guess I'll have to pick up a metal cutting jigsaw blade tomorrow and give that a try instead.

Pics when it's done ... or at least in a more advanced state than it is now

 

[ScrubNinja]

Metal jigsaw would be a much better option. Shit, I didn't even think about using that. Dammit. I have one.

Would definitely recommend painting flat as that's gonna determine a lot. How big will the final product be?

 

[squirrelfooker]

Seems to simple to actually work 100%. Looks like it should work with long enough pieces though, I'll probably give it a try.

 

[fatigues]

Metal jigsaw would be a much better option. Shit, I didn't even think about using that. Dammit. I have one.

Would definitely recommend painting flat as that's gonna determine a lot. How big will the final product be?

Not sure until the final spacers are all in and I'm content with the spacing.

I have 20 x 8" black vent louvers cut. If I use a doubled up version of the aluminum spacer material I have, it should work out to about 8"x4", overall. Smaller than I would like, I think, as that seems pretty tight for that number of louvers. If I can get away with tripling the spacer material and still keep it light tight, it will end up at 8"x6", which is what I was shooting for.

 

[ScrubNinja]

I think you will definitely have some noticeable light leakage if you double or triple the spacers but I guess it depends on the level of blocking you need. Just be sure to stack the pieces together before you glue it and because it's all so geometrical, they lock in and it can be held together without glue. Swivel it around and make sure you (at the very least) can't see through the louvres at any angle. So it's sort of a hollow wall. Even set it up in front of a CFL to get a loose idea of what effects your spacer differences have. Good luck man. I should be getting started on the new one the next few days.

Does anyone own a professional darkroom vent and can see how they work exactly? I've heard they work great but are very restrictive.

 

[fatigues]

I think you will definitely have some noticeable light leakage if you double or triple the spacers but I guess it depends on the level of blocking you need.

No. I suspect that doubling the spacers so its about 4mm between the vents will be fine. With some added thickness for the Lepage's epoxy steel adhesive I picked up, it might creep up to 5mm... I hope . That may push the overall vent size, as framed, to a shade under 8"x5" (4.75, actually)-- which I can live with.

Triple it to 6mm? I'm not so sure that will work, especially when the epoxy is figured in We are in agreement upon that.

Seeing as I have to go back to Home Depot, I may end up getting some more black angle, too. Problem is, at the cost of the angle, if I get another 2 sections of that, it is quickly becoming cheaper to just buy an 8x8 louver from B&H

 

[hoosierdaddy]

ScrubNinja, I applaud your thinking through and carrying out on your idea.
You are an official tinker, my friend. No doubt about it. It's an inherited trait that not all carry. The civilized world owes everything to the great tinkers.

I want to just throw this at you guys...do with it what you will. (wink)

btw...measure the thickness of the spacers, and multiply that distance times the distance between spacers, and that will give you the square inches of air flow through each fin.
Multiply that figure times the number of fin openings, and that will be the total square inches of air flow through the complete louver.
EXAMPLE:

.25" spacers x 8" between spacers = 2 square inches of air flow through a single fin opening.

10 fin openings x 2 square inches = 20 square inches of air flow through the louver.

As you can see, it takes quite a few fins to make up much air flow. That is why you see the high-dollar louvers you buy with so small an air flow rating. They are much more restrictive than they look.
BUT..with the figures I gave you, you can size and build the louvers to match the square inches of air flow at your exhaust. (remember to oversize your louver(s) by at least 10% more total air flow than you have at the exhaust port....a 6" round exit port equals 28.27 square inches of air flow)

 

[jump117]

V .vs. Z-N

V .vs. Z-N

Hey ScrubNinja it's a very good idea! You may also improve this jalousie from V profile to Z.

Self-criticism, Z- or N- profiles create pockets, your V-profile upside-down is the best.

I see a little possible upgrade in coating lamellas with soft sound reducing layer.

 

[ScrubNinja]

Hoosier, holy moly man! Way to go! I was hoping something like this would happen - firing people in a different direction. Wow man, props and thanks for the kind words!

Jump, au contraire, bro. That was my original criticism of the Z idea but it can work and in overall terms, I think it'd be best! The thing is, you'd need angle that was like if you grabbed the top left, and bottom right ends of the Z, and pulled them apart a little so the middle bar of the Z is parallel. But I'm not sure such a product exists. It's basically the same idea Hoosier has achieved. So it would look kind of like this but 90* angles:

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[0p0rat0r]

That's a sweet light trap idea.

 

[hoosierdaddy]

I was just throwing out an idea using easy to obtain angle material. Z's and such are usually custom formed channels.

A single fin will also work. But, no matter that you do it with, you have to take into account that the air flow will be restricted by the smallest passage of your louver.

In this sketch there is a single fin inside the box. This will block any light getting out the exit port, but the opening the fin made is not enough to satisfy the 28.7 sq in of air flow that the 6" round duct requires.

In this sketch the opening made by the internal fin is bigger, and allows full flow of air.

But...am I actually getting full flow of air?
I need to measure from the wall of the box to the fin...
And I find that I only have 2-3/4" space.

2.75 x 12 = 33
So, I have 33 square inches of air flow, and no matter how much more I shrten the fin, it won't help because the smallest port is between the wall and the fin.
Hope I haven't cornfused anyone.


I have fiddled around with light traps a bit, and always go back to using PVC elbows painted flat black inside. They take up room if you do them inside, but they are cheap and easy to work with.
A louver looks much nicer though.

 

[tommyboi_420]

very very slick ScrubNinja!!!!..this is rep power worthy people!!

 

[disfunktional]

Thanks for the good vibes all. Another thing I forgot to mention is that there's different designs of angles. Shorter on one side, etc. Might be good to play around with.

hey ScrubNinja hell of an idea. i think one side longer than the other would work great. if you flip from one side to the other with the longer side. meaning long side on the cab side then short side on the cab side and so on. i was rackn my brain trying to come up with a easier way to the intake with a light trap on my minifridge and this is perfect. i also found a site that has all sizes and materials of angle at a way better price than loews or best buy heres the link.http://www.onlinemetals.com/ im going to figure how much material i will need and get it ordered and as soon as i finish the fabrication il post the pics. thanx for the awsum post!!

 

[D.I.trY]

A++ scrub. They say the best ideas are simple: its so simple you gotta think somebody has done it before, although maybe not? Maybe you are the first person to make it from that material for this application in the world! I can't think of anything better you could ahve used than that right angled metal. This rightly deserves its own thread and a place on that awesome list. bookmarked it - thanks pontiac.

I've seen lots of that right angle metal stuff at my diy stores too. Just as a guess tho i don't think its primary use is for edging but for a structural purpose because the angle gives it strength, but i'm no expert!

 

[dyno]

Great idea for a light trap Ninja! I find I get the best ideas when high. Truly KISS

Gratz on making the Link-O-Rama !