Hey all,
Well, after months of reading, researching, re-reading and re-researching (I am a stoner after all...sometimes it takes a bit for things to sink in), going back and forth on whether I can do this or not, I decided to take the plunge in Feb and started my first grow.

I have reworked the PC case below quite a few times, but finally landed on the design below. It is by no means original as I have borrowed elements from this forum and others. I do have temperature problems though. I have two 80mm exhaust fans, one is a silent model that moves ~30CFM, the other is a non-silent model, CFM is unknown but it must be equal to or greater than the silent one. Both have home made carbon filters made out of plastic canvas, activated carbon and pantyhose. I am sure these filters reduce the exhaust fans CFM considerably. There is an 80mm silent fan in the front bottom bringing cool room air in. There is also a 120mm inside the box focused on air movement. I installed a sheet of plexiglass in an attempt to reduce heat over the canopy, and the 120mm fan is split, half going up across the bulbs, half going below the plexi and over the plant canopy. I also built a little stand to replace the books I was using to raise the plants to the lights. The books provided for no air movement whatsoever, so i screwed together pieces of 1x2 to make a stand.

Oh lights...these temps are with only a 40W and a 23W in there (the pic shows 2x23W and a 40W, i removed one 23w to help reduce heat).

In the picture below, the translucent red areas show the temp range in those areas. I cannot seem to get the area above the screen cooler than the low 90s. I dont know what else to do...the heat was worse before this redesign, had temps in the canopy of 99-103F and my plants were showing signs of heat stress.



Other pictures just for show...Peace





Circle Plant @ 34 days -- pretty sad


Triangle Plant @ 16 days

I've had similar heat issues with my grow box, generally above 90F the plants will get heat stress or stunted growth.

Suggestion #1
Leave the side panel off for most of the day, or when your home

Suggestion #2
Move the plant container to the base of the computer case, and move the lights down instead. That way there will be a pocket of hot air above the lights.

Suggestion #3
If possible, have the intake fan at the bottom, and exhaust fans at the top. That way it brings in cool air, and removes hot air that rises to the top. If you can't move the intake fan, you can redirect the air down to the bottom, that way it is constantly pushing air up and out.

I don't know how handy you are, but a dremel will make quick work of the soft steel inside your average PC case, allows you to add holes where needed.

Suggestion #4
Keep the PC case itself on the floor.

Suggestion #5
Use a piece of glass, or plexiglass as a barrier between the lights and the plants. Then you can channel airflow specifically past the lights. Kinda like a "cool tube" setup that larger grows have. Search this forum for that keyword if your unsure what it is.

Suggestion #6
Since you have plenty of fans, seal off any passive air leaks, so that only the air going in/out is controlled by the fans. If there is a steady stream of air going by it will force more hot air out when the side panel is on.

Once you get your heat under control you can move your lights closer to the plants. I have mine 1 inch away. The plants will be fine just as long as they don't physically touch. You'll need to keep a close eye on them though, when you keep them that close you often have to move the bulbs up daily.

lmn8r - thanks for the ideas. some i have implemented already (the plexi sheet between lights and plant, intake fan at the bottom) but two things you mentioned are brilliant and I will implement tomorrow morning. 1. Leave plant on floor and lower lights...heat rises...i must have been much too stoned to figure that one out! and 2. move my second exhaust fan up beside the higher one...i couldn't do that with a previous iteration of this box as that space is the fake power supply plug and switch...but as i am not actually using that - and stealth on the rear of this is not as important - I can put the sedond exhaust fan there. I have a dremel and it has visited this box a few times already...i did do the box above myself so yeah, i can be handy in a very amateurish MacGuyver way.

my second box is taller and coming along nicely...i am using things i learn with the first one perfect the second...peace

wow I didn't see the plexiglass sheet at all, and I stared at your pictures for a good five minutes last night.... man I must have been tired

these 60 hour weeks are killing me

sorry to hear about the 60 hour weeks...been a few years for me since I worked those kind of hours...anyways, i removed the stand, moved the light bar down to just about the middle of the case...2 inches above the plants...lowered the big 120mm fan and the plexiglass of course. temps are at 95F after four hours of the case being closed and lights on (3 x 23W CFLs). I didn't get a chance to move the second exhaust fan up next to the other fan yet...I must admit, i dont have much pressure coming out of the exhaust fans...one is rated at 23 CFM and the other at ~30CFM - I;d be surprised that with my filters that i'm getting anything more than 5-10 CFM...which may be my real problem. I'm thinking of picking up a 120MM fan at 80CFM and replacing the dual 80mm with...and maybe movign the more powerful 80mm to the top and have it exhaust upwards...leaving the cabinet door off is not an option as i need some stealthiness and that would raise too many questions...plus odor would become an issue...

so, perhaps plan B...a small 24 inch by 12 inch by 30 inch tall white cabinet in my closet (next to my shoe rack under my clothes) vented out to the attic with a real fan and carbon scrubber and passive intakes at the bottom...should be able to do two in that space...

Very nice case setup you have there.
Got a few things that may help with your temps:
Just for now those plants aren't too stinky so you can remove one or both of the carbon scrubbers to get it cooler and keep the plants going.
I think the plexiglass is nullifying most of that 120 fan and you may even find temps drop if you remove it. Best bet would be if you could bend it up and over the fan at the front end.
The low front fan is a bit useless too. If heat rises then cold air doesn't, so introducing it at the bottom is somewhat pointless.
If you can't move the fan up then block up the stand like it was before as this will channel some of the cold air upwards where it's needed.
Most effective way to deal with it long term is to leave the exhausts as they are but increase to 92mm fans if you can and to use all the top half of the front as an intake. This allows a proper flow of air across the plants. Leave the bottom (where the front fan is) opened up to act as a vent for excess pressure.

Good luck.

hi v12xjs (thats a jaguar reference, no? one of the most beautiful autos around...i saw a new Avanti today...oh shit...stoner is rambling)

anyways, thanks for the suggestions on the intake fan location (and the comment of the pc case...it's a blast doing this). I had been thinking along the same lines all day at work. before i read your post, i had decided to try removing the 120mm fan as i was thinking it was creating two separate areas of air...and the air below the plexiglass was trapped and building heat throughtout the day...within 20 minutes of turning off the fan the temps had dropped from 96.8 down to 85...and still cooling...so now i am at a comfortable 8-10 degrees above room temp.

i do consider these two plants throw aways (bag seed)...test cases..to help me build and perfect the case...and considering what they've been through...i'm amazed they're still alive...the circle plant is now 36 days old and as far as I can tell, has not shown sex...at least i can rule out balls sacks...i haven't seen anything like the pics i've seen of male plants. they look more pear shaped than balls.

anyways, thanks for the input and i will be moving things around a bit in there again next week...i hv to cover the passive intake spaces now...cant work on this anymore today...granddaughter is coming over

peace

Hey av
You're right, it's a reference to big fat Jag cars. I love cars
Glad you sussed out the temps.
I can't wait to see what develops in there, hope you're planning on sharing more pics.

Here's the latest pic of the 36 day old "freak of nature" plant. It's a close up of nodes 8-10...and I still cant tell sex in this picture. The two hours of light I had left yesterday after I fixed the heat issue resulted in some very impressive growth in Circle...Triangle (the little sis/bro) is doing well too. It's the weekend, so they get left alone for two days. We'll see how they do. My "local-only" pot-cam keeps an eye on them and makes a movie for me of the entire day's growth...taking 6 pictures an hour. It's so cool to come home and watch what my plants have done for the day. The 12 hour light session movie lasts about 12 seconds as I have it set up for 10 frames per second [ 1 second = 1 hour)

Circle: