DIY Growbox Intake/Exhaust questions

  • Thread starter Thread starter DiogenestheCynic
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DiogenestheCynic

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New to the forum and had a question.

I'm currently sketching up my first grow box; inside chamber dimensions will be 22"L x 22"W x 34"H which equals roughly 9.5 cubic feet of space. I plan on having passive intake holes in the bottom. I plan on using CFLs (probably Botwin's PVC light rig); not sure what size yet.

Would 4 120mm or 140mm computer case fans be sufficient to keep the case cool? Do I need more or could I go with less?

Mainly I'm just curious if this will be sufficient so I can add it to the sketch and get the placement layed out. If anyone can provide a link to some kind of calculator that'd be awesome.

I've got a real bug up my ass to get this build going, but stealth is of the utmost priority as I live with another who's not so inclined. I'm using Google SketchUp to work it all out; if you haven't checked it out, go download the free version. It's tits!

I'll post pics by tonight as I finish the design.

Thanks in advance for the help,
Diogenes
 
Here's a Print Screen pic of the cab sketch so far:

Cab.jpg

(I hope it's big enough for everyone to see.)

Since stealth is my main concern, I decided to try out a design using QuietBrace boards (info can be found here: http://www.templeinland.com/PDF/Fiberboard/qbsound.pdf). They run about $10 for a 4' x 8' sheet/ 1/2" thick. I also wanted to be able to vent out the sides, but needed a way to cover the holes without blocking air from flowing out, so the outside panels (sides and front) will be wrapped in burlap sack. Hopefully this will accomplish the same thing as the fabric over speakers. I also plan on using some sort of filter, probably the pencil holder DIY I found on here.

The hardest part right now is figuring out some sort of system for opening the door. My thoughts now, are to make the top hinged, and having the door lock/opener in the top compartment, but I haven't figured out how to secure the door panel. I need some kind of hing that pushes out than over. Sugatsune makes some interesting ones, but they require too much door prep for me.

More pics will be up tonight, hopefully. This will more than likely be a soil grow as well.
 
well at least you're planning ahead, i wish i'd done that. pays to take your time. happy harvesting.
 
It doesnt look like you have made any provisions for a light trap. You will need them on intake and exhaust if light discipline will be required. Also you will need around 2" of activated carbon for odor control as well. I used 4 120MM quiet fans in my original design and they kept the box cool but has to pull them to put in a real inline fan with carbon filter. You can see it in my grow box thread. Also you might want to consider adding more height at you have to take into account pot size and space between light and plant as well. with a 10" tall pot and 6" of lights attached to the top you just lost 16" of space so you might want to think about that some as well.
 
wildrunner - thanks, i started a build a few months ago but scrapped the idea due to funds. Actual construction should begin after the New Year.

Scott - as far as light traps, i plan on using the pencil cup carbon filter affixed to 120 or 140 mm computer fans. this should provide some blockage of the light. in addition, each panel will be predrilled for the ehaust/intake holes, then wrapped in burlap, kind of like the cover on a speaker face. I'm hoping this will help with blockage of the light.

As far as space issues, I only want to grow one or two plants. I may stick with short autos or try my hand at SCROGing. To reduce noise issues I want to do a soil grow, but they may change as time passes and my brain gets to fondle the idea.

Your guys' input is greatly appreciated. I want this box ironed out and complete before I look for some seed bank recommendations.
 
I rearranged the exhaust holes and changed my outline to fit 120 mm fans. May include a 3rd, with filters on only 2.

Quick question: Is it still beneficial to have a hood if you line the entire box with heavy mil mylar? (Probably 2mil min.)
 
wildrunner - thanks, i started a build a few months ago but scrapped the idea due to funds. Actual construction should begin after the New Year.

Scott - as far as light traps, i plan on using the pencil cup carbon filter affixed to 120 or 140 mm computer fans. this should provide some blockage of the light. in addition, each panel will be predrilled for the ehaust/intake holes, then wrapped in burlap, kind of like the cover on a speaker face. I'm hoping this will help with blockage of the light.

As far as space issues, I only want to grow one or two plants. I may stick with short autos or try my hand at SCROGing. To reduce noise issues I want to do a soil grow, but they may change as time passes and my brain gets to fondle the idea.

Your guys' input is greatly appreciated. I want this box ironed out and complete before I look for some seed bank recommendations.


Ok I have never seen the filter but I get the concept. You will want to look for fans that have a very high hydrostatic pressure rating. Your exhaust fans typically already have to pull air into the box for inflow. You will want to make sure your fans can pull through the filter with enough flow since that effects the whole box as well. So in stealth you will want to check the db level as well so look for the lowest db with the highest hydrostatic rating and you can check it then. Be careful not to get confused with the fan blowing air on the backside as what is actually flowing as that can be tricky.

I look forward to seeing it done :)
 
Also, keep in mind I'm using QuietBrace, a structural sound-insulating material. The PDF link I posted above claims that it reduces noise levels by 30% compared to conventional building materials. It's also cheaper than plywood per sheet. Sandwich 1/2" thick piece between two 1/2" thick pieces of ply, and you'll get an idea of my side, front, and back panels.

My other goal is to make this look purposeful; not just some box that doesn't seem to have a door or function. I'm toying with the idea of making the top into a bookcase shelf of sorts; the bottom will be hinged so you tip the whole top shelf back to reveal the top compartment (above lights, below books). That part may have to be tweaked.
 
Ok, so I've been puzzling on how I want to keep the door panel secure without having to use a hinge. I found some info about Quaker locks (mainly used for drawers) and got this idea. I wanted control of opening the door to happen from the upper compartment, which I will have further secured by a hinged/locking lid/top. I have some experience with metal fabrication, so I don't believe it will prove difficult to make it, but I'm not sure if a) it will be strong enough, b) if i'll need further catches at the bottom (and if so, how to open those), and c) . . . I dunno.

Anyway, I mocked something up, and it seems pretty good. I'm looking forward to a field test.



DOORIDEA1.jpgSpeaking of, donations (in the form of scrap wood, computer fans, nails, saws, a McRib) can be sent to: Diogenes
Bathtub Pl.
The World :toke:
 
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