Which Cabinet Would You Go With ?

more pics....

final few pics......

thats just great bro, awesome job!! be sure to post the link to the grow.

Ut oh....I just ran 22 cfls in the flower chamber for a few hours with the exhaust fan on.....temp started down here at 63....flower chamber was at 93.....

I still have 10 more cfls to add in there and four T5HO strip lights.....

Any ideas how to get the temps down ?

The fan is a 4" 80cfm....I have two 2" intakes (passive).....

Do I need more intakes ? I thought I read somewhere that your intakes total size should be twice what the diameter of your fan is......I also only have a very short pipe coming off the fan before it totally exhausts....I think it's only 7".....I thought I read your exhaust pipe should be at least 3x you fan exhaust diameter....Do I need to lengthen that perhaps ?

Could I use a PC fan for an active air intake ? I could even get that 63 degree starting outside temp down to 60 probably

I had the thermometer attached to the chain above the lights...Maybe the temps are hotter above the lights ? I just put the thermometer on a box in the middle of the grow cab under the lights....I'll let that go for an hour or so to see if the temps are any different....Can't imagine them being too far off....Plus I still will be adding 300 watts or so of lighting to this beast.

Temps were already up to 100 degrees after like 10 minutes....

I reinforced a seal that could have been leaking but I don't think that is much of an issue....

I am a bit worried because there is nothing blocking the fan....At some point I plan on putting an AC filter in there with some activated carbon for my scrubber....that will even further reduce the airflow....

But you had fun building it! Definitely need more holes, and more exhaust. I wouldn't worry about adding intake fans.

Ya I got the tunes goin', and went to town...I have an imaginative/creative mind so it was fun building this...Now I just want to grow ! lol

First step I think will be to cut two more 2" intake holes in the floor...So then I would have the four 2" intakes vs the 4" outtake....

What's the true wattage being pulled? My 600 in a 4x2 tent used a 435cfm exhaust. That's with the ballast out of the tent. 600 watts of CFL are probably hotter than a 600 hps. If all else fails, thro an LED in there!

Hey space..cool box!.Your exhaust hole should be larger than the intake to insure a negative pressure in your box.That being said...you need to make bigger intake holes....make the two existing holes one bigger one,if possible.I looked online and from what I gather my exhaust fan is running at about 750cfm....it will suck my closet doors closed if they're open a few inches

800 watts - that will be between the cfls, and the four T5HO lights and that's just in the flowering chamber....

If you want to include the two veggin chambers....Each of them can house 9 cfls....So if they were going all out too you would have to add roughly around 450 watts more.

B166ER420 said:

Hey space..cool box!.Your exhaust hole should be larger than the intake to insure a positive pressure in your box.That being said...you need to make bigger intake holes....make the two existing holes one bigger one,if possible.I looked online and from what I gather my exhaust fan is running at about 750cfm....it will suck my closet doors closed if they're open a few inches

Click to expand...

you sure you don't have those mixed up ? My exhaust hole is larger than the intakes right now.

It may not be a good idea to hide a grow, no matter how well hidden in a high foot traffic area if you sell (anything out of that area) that people are near, unless your light sealing is FLAWLESS, your filters are top notch and absolutely free of blockage, or tears in duct, etc, and most of all... Noise, fans are fucking loud, if you can absolutely make it SILENT, SMELL free, and LIGHT proof that's a hell of a mission. If your up to that, and all the frustration with it, go for it. But if not, I would put it someplace else, or not have anyone down to that area you would not do time for. If legal, sure its a little dif but I just assume its not. Especially since it's meant to be "hidden".

Positive I don't have em mixed up.You definitely need a stronger exhaust fan or possibly two.


If I had a small exhaust hole with bigger intake my fans blowing inside would create a positive pressure...lowering the effectiveness and making the exhaust fan work harder..and blowing smell out any smell in cracks or leaks in your box.I have a smaller 2x2.5x4 box also..I used to run it with 16 cfls.

bro, you need a 2 to 1 ratio for a passive intake system, 2 times bigger exhaust than your intake. the exhaust fan will suck in the air. did some searching on this, check this out.

use only exhaust fans at the top of the cab where the air is hottest with passive intake hole(s) near the bottom (best to use several small intake holes spread out evenly along the bottom)

here's the first and most obvious reason as to why not to split 2/2

If you are pulling air out the top with 2 fans at 150 CFM, that air *has* to come from somewhere, it will pull it through your passive intakes.

What would adding 150 cfm of in-take air actually do? if you are pushing air in at the same rate you are pulling it out anyway's, you haven't actually gained anything. the exhaust fans might not have to work fractionally as hard, but not a noticeable amount. Think about it like this... if you set the cruise control in your car at 10 mph, and then somebody starts pushing your car from behind at 10 mph, your still going to be only going 10 mph, you might just burn a little less gas in the engine because some of the work is now being done by something else.

The other reason I can think of is that, in general, having a slightly negative air pressure inside the box (you will have negative pressure because the fans will be constantly pulling air through the intakes trying to get them to keep up with the rate its pulling it out, it won't be able to do this perfectly, which will create slightly negative pressure). This is a good thing because negative air pressure = less air = less heat capacity which means the hot air will rise to the top quicker and ultimately get exhausted quicker.

the other issue with using combo intake/out take is that you can create sort of channels of air flow that go directly between the intake fan straight to the out take. This happens because the air coming in is being pushed into a certain direction at relatively high velocity. ultimately this can create spaces in the box that doesn't get its air exchanged frequently and becomes "stale" so-to-speak... sorry I know this particular point probably makes absolutely no sense... I can completely visualize it in my head, but I just can't seem to put it into words lol


the best thing IMHO, put all your exhaust fans spaced out evenly across the ceiling of the box if possible. then drill many very small holes (in comparison to the out-take holes) all the way around the perimeter of the box near the floor of it, this should help keep air being exchanged throughout the entire box.

If you want to get like super awesome... you could build like a raised floor inside the box and have all the in-take holes in the raised floor, that would keep fresh air coming directly up through the floor, past the plants, up to the lights and eventually out the exhaust. I actually really wanted to do that when I built my box, but lazy ness got the best of me!

OK I guess I misunderstood ventilation from the beginning plus I have someone on another forum to cut more intake holes, grrrrr..

OK well I think What I am going to try at this point is to do all new holes.....Cover up the existing at start anew....

HERE'S THE PLAN:

Exhaust diameter is 4"....

So I was thinking of going with a 1" hole in the top of the vegg chamber, and a 1" hole in the top of the flower chamber.....then I would put a 1" hole in the floor of the vegg chamber, and a 1" hole in the floor of the flower chamber....

Anyone think this might work a lot better ?

CD, sounds like too much work to me too, lol...think I'll just let my pc fans blow wind on the plants, lol

EDIT: or since it is a two chamber cab plus it has the "chamber" up top where the fan is should I go with even smaller holes ? Technically it has to suck air out the top chamber as well as the veg and flower chambers....

Maybe should I go as small as 1/2" holes ? I can always make them bigger....If I make them too big again, I'll end up having to patch them like I'll be doing tomorrow

B166ER420 said:

Positive I don't have em mixed up.You definitely need a stronger exhaust fan or possibly two.


If I had a small exhaust hole with bigger intake my fans blowing inside would create a negative pressure...lowering the effectiveness and making the exhaust fan work harder..and blowing smell out any smell in cracks or leaks in your box.I have a smaller 2x2.5x4 box also..I used to run it with 16 cfls.

Click to expand...

You have it right, but still backwards Its negative pressure that pulls doors shut and positive pressure that pushes them open.

Lol...I'm an idiot....I haven't smoked any yet this a.m....and with a clear head,i immediately see that!I reread that a dozen times and didn't catch that...As soon as I seen your post it clicked!Thanks for setting me straight!peace


Yes...negative pressure good,positive pressure bad

Having major heat issues....Actually hit 109 at one point...I only have 22 bulbs going in the flower chamber right now too....This sucks...

I may have gotten too small of a fan...That "scrubber" I built might be ok for the smell but not heat !!! I didn't think that would be an issue...I guess I just thought the fart fan scrubber would take care of the heat as well....

At this point I closed off the veg chambers from ventilation, and I am using a pc fan in the floor of the flower chamber for an active intake....Not sure what else to do.....

I boarded over all the 2" holes....then drilled 1/2" for intakes...that fart fan was hardly pulling any air through....I'm going to check on it soon to see if my latest tweaks did anything...

this sucks...I just had a tap root pop out of one of my seeds...I'm sure the next tap root is next....damnnnnnnnn...

F me....last temp was 93....I just added a pc fan on the light fixture to see if that helps get temps down....

I'm in full blown MacGyver mode right now.

Anyone know what kind of temps c99 can withstand ?