Before i get started, i just want to address 2 points with my guide/pictorial... Firstly, I am writing these in 'Layman's terms' meaning that any reference to power, wattage, airflow rates etc. is simplified to the point that they can be easily understood by anyone without the need for complex math to baffle people and detract from the point of this guide (so please no nerd posts about my math not being exact) Secondly, But more importantly... The fact that not all PC fans are the same! There are 2 types of fan which you may recognise as a generic 'PC Fan' unless your are already aware of the difference and how to spot it.... There are: 1. True PC fans which are specifically for use in PCs. They are designed with Operational db level as their first and foremost priority, followed by there capability to move a set volume of air per/min generally labeled in 'cfm'. They are not designed to be efficient at working under positive or negative pressures as PCs are designed with unrestricted airflow in mind, they are most commonly designed to run in tandem (ie. a fan pushing air into the PC and another pulling air out of the PC ) A typical 120mm PC fan will average around 80 cfm with no restrictions, 2. An 'Axial fan' or 'Axial Chassis Fan' which looks identical to a generic old skool PC Fan! These however are of much higher power than a PC Fan, run faster, are capable of creating a higher positive pressure (the ability to force air through a restriction such as a filter[/]) the down side to this is there noise or db level when running which is much higher than a PC fan.... if you put one of these in a pc you will know about it! lol For those that don't know the difference here are 2 pics: a 120mm PC fan with molex connector and the volts and amps tag visible, this is approx a 4.3 watt motor. a 120mm Axial Chassis fan - note there is no connection block and the ground wire is not black! (this identical size fan has a 9 watt motor. My Next Posts will be the Pictorial on making a simple but very effective extractor with carbon filter for a stealth cab using a few junk pc fans and an axial fan If you are only venting a very small or micro cab then you can get away with using all PC fans i will explain this slight modification in the guide!
Right... lets get started with parts and tools lists Parts: 2x - 120mm or 80mm PC fans - £0 laying about in my pc bits box 1x - 120mm or 80mm 12Vdc Axial fan - £4 4x - 65mm M5 machine screws (75mm cut down!) - £0.25 each (hardware store) 3x - 130mm x 130mm woven steel mesh (Recommend 1x1mm holes) - £0 laying about! 1x - Box of loose, Activated carbon pellets - £2.98 (from pet shop, keep well wrapped and it will last 3 or 4 filter changes!) 1x - Roll of 50mm Aluminium tape, or gaffa/duct tape! - £0 you cant not have this somewhere! Total - £7.98 Under £20 if you have to buy everything needed Tools: Screw drivers - cross/spade head Cordless drill with 5mm drill bit (not required but makes life easier) Tin snips Side cutter Stanley knife Dremmel mini drill (or similar) with sanding drum (not required but makes life easier) now moving onto the pictorial...
Woo... Pictorial time: 1. Cut fan out of 2 fan casings ( if using all pc fans just cut 1 out) 2. Clean off the edge using your Dremmel drill. 3. Using a 5mm drill bit, drill out mounting holes in the fan and 1 fan casing only. Slide the machine screws through the holes in the fan. 4. Lay fan down, and place one sheet of mesh over the screws (use a pozi drive screw driver to widen the holes in the mesh so you can push it down) 5. Take fan case with the holes we re-drilled earlier and slide onto the screws next! 6. Now take your activated carbon and fill the fan casing, gently tapping the carbon down to get it to settle. You just want it packed in enough so that when you stand the cartridge up when finished that the carbon doesn't settle and leave a big gap at the top edge! (a little gap of 1-2mm won't be a big problem!) But you don't want it crammed in that tight that air won't flow through it either I find that when you have tapped the carbon down if there is a slight dome of carbon in the centre, about 2-3mm higher than the edge of the fan case this will be plenty extra to allow for any settle! (I haven't added the carbon in my pictorial... because i used 2x2mm mesh i had to order larger pellets which are hard to find, and i'm still waiting on the post for them! ) 7. Take your second sheet of mesh and place this over the screws and slide it down to hold the carbon in, don't worry if it bulges in the centre where the carbon was a little high, as long as you get the mesh against the edge of the fan case, its all good! Use some gaffa tape to hold the whole assembly together for the time being... Tape it as if you're tying a parcel! one piece all the way over the mesh, down one side, across the fan, back up to meet on the mesh again... then repeat at 90 degrees to make a cross shape! 8. Now that you have the cartridge held together with tape, go ahead and get your last fan case, the one i told you not to drill out (or your last fan if using just normal PC fans) Go ahead and get your screwdriver and you can now start to screw the last fan case (or fan) onto the cartridge assembly. Work your way from screw to screw only tightening it down about a 1/4" at a time, if you screw one side up too much more than the others you will twist and crack the fan casing! When its screwed down, just get it tight enough to hold it all together, don't over-tighten or you can strip the threading in the plastic. You can now trim off the tape that you were using and will look like this: 9. time to trim the excess mesh using side cutters or wire cutters, finish off with a once over using the Dremmel to take any sharp edges off! 10. You now have your almost finished filter. One last job to do is to make sure you have a good seal around the edges.... Queue your Aluminium Ducting tape (I used orange gaffa tape as an example, but when you do this needless to say you would put tape all the way round! When the carbon goes in mine i'll be using Aluminium tape to seal it with! Start by laying a piece all the way around the centre, covering both mesh joints! rub it down into all the corners and make sure its properly stuck! 11. Next lay a second strip overlapping this strip halfway and allow enough to fold over the end slightly. 12. lay another strip overlapping the other end and again leaving enough to fold over the edge again. All done, ready to mount in your Stealth cab! Total build time approx 1hour 20mins Here is one final pic of the 2 i knocked up for my cab, just waiting on the postal service for my carbon pellets... Grrrs! I hope that you liked this guide, it was easy enough to follow and detailed enough to make sense? If you liked this and found it useful, please vote to make this a Sticky thread! Hot wiring an ATX PC power supply to run your fans: http://forum.grasscity.com/do-yourself/1286921-hotwire-pc-power-supply-use-your-stealth-cab-pictorial-stews-guide.html Building a Stealth cab Pictorial: http://forum.grasscity.com/grow-room-designsetup/1287370-stealth-cab-build-school-locker-style-cabinet-pictorial-stews-guide.html Search "Stew's Guide"
Very effective for 1 to 2 plants per extractor! The 25mm depth of carbon thats in the filter is equal to or a greater depth of carbon than a big canister filter! Ie. The air is moving over the same amount of carbon per square inch as a big canister filter. For extra filtration if if using the higher power Axial fan you can also add carbon and mesh to the 2nd fan casing, thus doubling the volume of carbon that the air passes through This is a versatile modular design, if you want more carbon just add further fan casings and mesh! I would recommend adding mesh between each carbon filled casing as it stops excessive settlement of the carbon! I will probably add an extra carbon layer myself but for the sake of the pictorial i didn't show this in order to keep it short... I should probably have mentioned it though! If you are asking is the carbon as effective as an off the shelf canister filter, the answer is 'Yes' it is exactly the same carbon as used in them... You just pay a crap load more because its been pre-manufactured for you.... However they are generally too large for smaller Stealth/Micro cabs! Although its also Subjective! Depending on how well sealed your box is to start with, any air escaping without passing through the filter will cause smell problems. If your air input fans exceed the volume that the extractors can move you will force unfiltered air out of the cab through any gaps leading to smells! I have 140cfm air intake volume, and my extraction volume is 240cfm unfiltered (approx 180-200cfm with filters) this creates a negative pressure pulling air in through any inevitable gaps!
(so please no nerd posts about my math not being exact) I'm not a nerd nor am I "technical" in any way, as a matter of fact half of this stuff is over my head. I just enjoy looking, reading, researching and hopefully learn something along the way - I just thought you throwing that out there, from the get-go, was funny and probably much needed!
Lol, yea... Well there was method in my maddness! I'd read a few guides where airflow or lighting was mentioned in a layman's fashion just to give an abbreviated insight along the way. And then the next 3 pages of replies were nerdy posts condemning what was said, getting technical and the OP then trying (in vein) to explain it was only mentioned as a simple side note into such things! Lol
Job well done bro. I'm going to try and incorporate this into my micro cab build. Thanks for making this DIY!
Glad this guide was of help to you! If your doing a micro build such as a PC case grow you can suppliment the carbon with carbon impregnated filter foam which will be just as effective but not as messy/dusty! http://www.ebay.co.uk/itm/10-x-Carbon-Aquarium-Foam-Filters-Juwel-Jumbo-/160723417887?_trksid=p2054897.l4275 As long as its not in direct light it still acts as an effective light trap too!
@[member="Stoned_Stew_UK"] +rep for this guide - it's amazing. I will soon be implementing this technique, but just have a couple of questions I hope you can help me with first so that I can plan out my own grow. 1) What sized grow box were you using? 2) Did you just use the one carbon filter? 2) How long did the carbon last before you had to replace it? Thanks Sent from my iPhone using Grasscity Forum
Thanks dude, glad you liked it 1. Dimensions are 370x400x840mm (WxDxH) and stands a total of 1000mm including the legs 2. I used 2 filter 'units' in the cab 3. Lasted around 6 weeks but would recommend changing 1 unit every 4 weeks for best results! (it only holds a fraction of the amount of carbon that a standard 4" filter can does so obviously needs to be changed regularly) [bold]The stealth cab pictorial in my signature is what the filters were fitted to![/bold] Though i would recommend either using just x1 200w dual spectrum CFL or an LED panel in a cab that size as i had heat issues with 500w of CFL that it was initially fitted with! I re-fitted my cab with a 150w reflector panel LED from TopLED, and it is now running a dream!
Hey stoned great guide waiting in my fans to put one into my stealth cab. A few questions: Do you think screen used on screen doors will work between the fans? Will one of the be enough to give me proper ventilation and stealth in my small box. Dimension 19x15x22 in.