Impending PC Grow - Fan advice

Hi all,

I've been lurking around these forums for a while now, and the micro grows that are going on here have inspired me to start my own PC case grow! As well as being my first micro grow, it will be my first grow, period, so I'm looking forward to the experience!

Anyway, I'm at the stage of ordering parts and I'm currently looking at 80mm pc fans. The PC case will be in my bedroom, so plant odour and fan noise must be kept to a minimum. I intend to use a carbon scrubber to control odour, however this will necessitate the use of a powerful fan and as fans generally go, the more airflow the more noise.

So my question is this! Can anyone suggest a reasonable cfm value so I can get to looking for the quietest fan that will do the job properly?

As far as my design goes, I have two pc cases, which I intend to fix together side by side with a middle partitioning wall. One case will house all bulky electrical gear (plugs, timers etc) and a mother plant, and the other will be my main ScrOG grow area. I'm planning to have a passive intake positioned in the main grow area, with a fan on the partition wall (light-trapped), simultaneously cooling the lighting and circulating air to the mother room. The exhaust fan with scrubber will be located in the mother room. Total internal volume is approx 1.9 cubic feet (0.95 cubic feet per case).

I will upload some concept pics later on today if that would help any.

Thanks taking the time to read!

pics?


the idea sounds good, what lighting will you be using in the main chamber?

Hi there rkone. I plan to use two 30W CFL's in the main chamber - two 6500k for veg, then two 2700k for flower. In the mother chamber I'll be using a single 30W 6500k CFL.

Here are my concept plans with all panels removed for clarity (except from the important ones from a functional standpoint). If anyone has any suggestions/improvements/words of wisdom please let me know as all I have done so far is strip out the cases - the design is still very flexible!





Cheers.

thats lookin pretty wicked man, but with my experince (very little, im still in my first grow lol) with pc fans, is that u need a very powerful one to blow air through the scrubber, i have 2 fans, one on each side of the scrubber, and the airflow is very bad.
im going to invest in two 120mm Papst fans, i suggest you do the same they are pretty good fans, blow like 100m3/h each.

hope it helps, happy growing!

Nice design man! With how clean looking those diagrams are I can't wait to see how your box is going to turn out!

But anyhoo, you wanted to know about 80mm PC fans right? Well, over the course of building 4 different PC case growboxes and trying probably 15 or 20 different small PC fans the best compromise I've ever found of noise VS power in small PC fans are these fans 90mm Thermaltake fans from Newegg ---> http://www.newegg.com/Product/Product.aspx?Item=N82E16811999108

They push about 56 cfm and only run at 35dba, so the noise level is pretty low. However, if you really need your box to be ultra quiet the next best thing I've found are these 80mm fans from Thermaltake as well ---> http://www.newegg.com/Product/Product.aspx?Item=N82E16811999107
They push 37cfm and only put out about 30dba (sounds like 22 or 23dba to me though).

It's an unfortunate fact of fans that the more air they push the more noise they will generate, but these two fans I've recommended are the best compromise of power VS noise that I've found. They'll still make some noise, but you can dampen it a bit by installing noise reducing PC fan spacers between the fan and the wall it's being mounted to.

Hope that helps and please keep us updated on the progress of your growbox!
I'll be watchin'

Cheers for the responses lads.

Anonym, I hear you with the 120mm fans - I think they would be ideal but unfortunately the rear panel on my cases can only accommodate 2x80mm fans per panel. I want to maintain a degree of stealth about the outside of the case, so I would like to keep outside modifications to a minimum. With this in mind, would you guys recommend me substituting the existing 80mm exhaust fan as per the diagrams above with two 80mm fans, fitted flush with the rear panel simultaneously drawing air through a modified scrubber? My only reservation with this design would be the relatively large increase in noise. The alternative to this of course would be to bastardise the rear panel with a drill so it could accommodate a single larger (92mm) fan. I'll have a think about that, along with taking any ongoing advice into account!

Mr Micro, thank you for the response. I’ve been watching your Nanomachine thread with great interest ever since I stumbled across these forums. I wish you luck with your upcoming harvest! Cheers for the recommendations, with regards to the 90 (92?) mm fan I have found a comparatively well-performing model, claiming 62cfm @ 34dba (http://www.quietpc.com/gb-en-gbp/products/92mmfans/kaze-white-92). I'm attracted to this in particular as it looks like it comes with a potentiometer type speed controller (as well as LEDs which will be getting the chop!).

In your experience is modifying the 80mm fan mounts on my case to fit a 92mm fan worthwhile? I don’t want it to look crappy - I want to keep modifications to a minimum due to my lack of metal cutting tools/craftsmanship!

Hmm! Decisions decisions!

Hey Godisadj!

Given the nature of your PC case and size limitations, I would suggest that if you want to go for the full stealth route (something akin to my Nanomachine design) that go with the a 80mm fan just to keep it stealthy. I've had no problems keeping things cool in my Nanomachine using an 80mm fan pushing air through the carbon scrubber, so if you're exhaust fan is pulling air through instead of pushing that should work even better!

So personally I'd go with an 80mm fan since that's what your case is built to hold and if stealth is the most important factor than you want to keep it looking as much like a PC case on the outside as possible. That fan you posted a link to does look pretty darn nice, but it will ultimately come down to if you feel you can drill some new holes to mount the fan without making it look suspicious. And remember, heavy duty 5 minute epoxy is your friend! When you cant screw something into something without making it look out of place, just get some heavy duty quick setting epoxy and glue it in place! I think I went through 3 or 4 tubes of that quick setting heavy duty epoxy when building my Nanomachine, and the only power tool I ever used was a dremmel tool. So you could always glue the new fan in place if drilling the case would make it look suspicious.

And thanks for the kind words about my Nanomachine and the upcoming harvest! It's without a doubt my favorite growbox that I've ever built and I'm pretty excited for the harvest too!

Best of luck in your project and please do keep us updated mate! Also, if you have a link to a place online that sells the PC case your going to be using I'd love to see it! I really like the idea of a seperate chamber for a mother plant or seedlings so I'd really like to find out where I could get a PC case like the one you're going to be using

If your going with an 80mm PC fan, Sunon makes fans that push TONS of air! I am currently using one in my grow. You might have to purchase one on eBay for cheap.

I think I'll be going with an 80mm fan - if I come across airflow problems I might just add a second 80mm and mod the scrubber, but I'll cross that bridge if/when I come to it!

Mr Micro, unfortunately I cannot provide you with a link as I didn't buy online - I bought my cases from a local PC repair shop here in the UK. I paid £32 for the two, the external dimensions are 44x21x45cm and the cases came complete with front panel indicator LED's which I may still utilise in some form. We'll see how it goes!

I'll keep you all informed, and you can be sure I'll be picking your brains when I come across my next problem (probably very soon!).

Oh, I meant to ask - can anyone suggest a compact light-trap design for the partition fan? I found the below sketch on google images, would something as simple as this work whilest not inhibiting air flow too much?

If your going to use a scrubber, may I offer something for your consideration:

Cooler master Aero 7 80mm blower with speed controller:






or


Thermaltake X blower (comes with standard flat fan, blower, and a speed controller which controlls both:




Both are only about $30

Hi Lemon, whoa - those things are beasts! They look very interesting and I will be taking note of those models for possible future builds. For this build however, I think they'll be too noisey and take up too much precious space! I'm definately sold on the idea of a speed controller though.

Any views on the light-trap?

That CAD drawing looks really close to my server case. I am using a 4' 110cfm 120v AC fan as my only fan and it seems to be doing fine so far. As far as light trap goes that picture is exactly what you want to do. I have seen people use tissue boxes very effectivly. I think it was on redgreenerys grow tubs thread.

Good luck!

Hi Mr Ed, indeed I drew a lot of inspiration from your Weed Server as well as Kernel Panics dual PC case design! I love the stealth of the PC cases married with the extra space that two joined cases (or a lovely server case as per your design) gives.

I've ordered two 80mm ~50cfm fans for my ventillation, so hopefully airflow will be ok but I'll play this one by ear...if I find I need more I'll try to find a way to accommodate another fan!

I'm glad that you approve of the simple light trap design, hopefully I'll be able to come up with a nice compact design which doesn't infringe upon my grow space too much!

Thanks for the advice,

Cheers.