Building a 1/3 Scale Carbon Filter

Discussion in 'Grow Room Design/Setup' started by itsmysubaru, Feb 13, 2009.

  1. Welcome container fans and otherwise DIY-inclined readers, thanks for stopping in... I've been collecting suitable containers and bottles for the last week or so, while waiting for my fan to arrive. Now that it's here and I've sorted out the thermal control issue that I had (thanks to the help of GC), I'm ready to make a proper DIY carbon filter.

    I'm going to be using these containers, and maybe even a little hardware cloth from H.D., as well as caulk and aluminum tape for a nice seal and a little reflectivity. As you can see there is neither caulk nor mesh on the table. That's for tomorrow, you know, a nice little Saturday. I'm hoping to have this thing finished and installed by the end of the weekend.

    Here's what I've got to work with: ... If I can't accomplish this I'm an idiot! :D


    My main design points and goals for this project are as follows:

    1) The filter must flow. Heat is an issue in small containers with even as little as 100W, and this filter will be doing all the exhausting. A/C on the intake is not happening, as this would more than double the electricity budget for this build, so I've got to make sure the cab can breathe. Since my fan is (I hope) powerful enough, I've got to design the filter well enough to address both issue 1 and 2.

    2) It's got to pass the nose test. Since my Rubbermaid will be close-ish to my front door, I don't want anyone delivering food or passing by to be able to smell it. Chances are, if friends are over they'll be smoking as well, so it's not imperitive that this thing be 100%. 99 and change will do ;)

    3) That the filter is small enough to fit inside/above an otherwise space restricted 18 gallon Rubbermaid container. This also means, for me, that the filter must be self contained, with no ducting. Fan and filter as one. If possible, I'll design the unit so that the fan can be easily attached, with one of the lids I've got.

    4) And finally, of least importance I guess; that the filter will act as a muffler for the 45db fan it will house. I'd really like to keep this unit quiet. The 80mm fan was great on the ears, but flows barely enough to keep the lit cab cool, un-filtered... I'd like to keep the noise level as close to that as possible with this new fan. I know the carbon will help with this, just not sure how much.

    So, that's the plan... now to get to getting! I've already got my eye on that pencil cup. I'll be sure to post up the final product(s), and installed. Thanks for checking out my thread, I hope this helps some other beginners on their way to making DIY filters. :smoke:
  2. Oops, there was more to my post!

    As you can see I've already messed around a bit, but my new fan is bigger (and much more powerful, 70cfm, 20mm S.P.) than the weak 80mm I had planned on using at first.

    I plan on making a couple good, working units. One with maybe a quarter inch of carbon, and one with half an inch, to use just in case. I'd rather use the thin one though, because these fans can't overcome too much restriction. I've heard a quarter inch should be sufficient, is this right?

    Clearly I won't be using this stuff for a couple filters, even if they will be put together with a few items each. I'll keep for some choice ones as clone containers for my upcoming build, and back to recycling go the rest.

    Off I go!
  3. Due to the overwhelming demand and extreme enthusiasm shown in this thread, an update is forthcoming... here's what I'm working with right now:


    And the materials for V1 of my DIY Scrubaru :smoking:


    Will update after I partoke of the Ganj.
  4. Much better :D

    So the duct tape rolls are temporary, as I wouldn't expect them to last too long with the humidity (just asking for mold, too). I'll replace them when I find suitable plastic for the job. I had to build up one side of the roll of tape to fit it snugly into the slightly larger diameter pencil cup, so something sturdy with a taper and good inner diameter is still on my list (McD's later!). The plastic jar is from a container of almonds, cut in half.

    Went to H.D. on Monday, and bought hardware cloth and duct sealant caulk. I figure 10 bucks toward a complete seal and a proper casing can't hurt. I took the extra time to measure out the hardware cloth and it definitely paid off, the cylinder is perfect. There's about 3/8ths of an inch between the inner pencil up and the outer mesh. Course there will be black pantyhose over each layer, and carbon between. I plan on putting foam around the ends of the unit so as not to waste carbon where it's not needed, and also to support the base/top of the pencil cup.




  5. dude thats realy nice but my question is what do you use to power the fan because i have a bunch of them around and i would like them in my room for air movement
  6. Hey jamesdiplomat; thanks for the comment brotha. I use an old AC/DC adapter I had laying around from a FoxLink Router. The adapter is rated for 12 volts DC, and 1000mah (1 amp). You can dig one up from your closet, but just make sure you have enough power! Another alternative is to go to an electronics store and buy a switchable adapter, which is nice because then you can control fan speed by lowering voltage. Good luck!
  7. Bump because I just found my caulk gun :hello:

    Should have an update tomorrow, hopefully I'll get 'er all put together.
  8. i like......i like alot, wanna do GC a big favor and post a step by step quide on how you built your carbon scrubber, it would def help out alot of folks round these parts!
  9. #9 imstoned, Feb 18, 2009
    Last edited by a moderator: Feb 18, 2009
    quick back to the fan wattage or whatever what would happen if i powered a 12v rated fan with only 5v is that cool?
    sorry didnt want to be a jackass and not give you props on your setj up so far man
  10. 5v from 12v should be no problem, it'll just run the fan slower... B.P., thanks man, I'll be putting up a full detailed how-to once all the caulking is done and stuff. Gotta include those final steps! :smoking:
  11. So, I let the thing sit as it was for the last month... until my girl tossed out one of her moisturizer cream containers, I knew the second I saw it... perfect fit! :smoking: It eliminates that duct tape roll, which I was using as a coupler. Cardboard is a no-no in humid, hot conditions, so this plastic was all I needed to go from pre-fab, to finished :)


    Here it is glued in. Not quite optimal airflow, but it'll do. The fan has just over 80mm blades, this bottlenecks to around 75mm, inner diameter.


    Nice and even, about 3/8ths on each side for carbon. Now it's time to break out the pantyhose!





    Now something to seal the top. The glue I used pooled at the bottom, and will be airtight... but cotton will save me some carbon where it's not being used.


    I used a chopstick to get thirds of cotton balls down around the edge, until it filled up nicely. Take your time, don't want to get a run :eek:


    Finished with cotton for the top, now time to fill 'er up.


    This is after 100g of carbon. I had to break into another bag to get just a little more to top it off with. No more than 120g total, though.


    Cotton again, to seal around the bottom. Yes, that's a ketchup cap!! It separates the base plastic from the pencil cup perfectly. :D



    All finished. Easy to build, easy to take apart and refill! I may keep it out for a few tests, but I don't need it now... and won't anytime soon. For now, I'm going to put a garbage bag over it, nice and sealed, and see how much air my high-RPM 70CFM PC fan can push through. I'll let you know!
  12. Welp, tried to connect my adapter to my fan... heard a pop and smelled electrical. My NMB unit is toast :(

    Maybe I'll get another PC fan... but I'd been saving for a proper 4" mixvent, so chances are I'll just wait 'til then. I'll get a replacement PC fan, too, so those tests will still be done, just won't be a permanent solution.
  13. Well, I've decided to just wait on the 4" inline/mixvent fan, and use that fan (100cfm with a decent pressure rating) with this filter.

    I'm building another filter, a smaller one. I'll be using the construction methods, but on a 5" scale, for a curing box filter. The idea is to step the fan size down to 80mm, still a high rpm unit, ~60cfm or so.

    In the meantime, here's a shot of the completed (and completely sealed) filter.


  14. Price tally:

    Pencil cup: $1
    Cotton bawlz: $2
    Panty hose: $3
    Glue: $4
    Hardware cloth: less than .50c worth of material, $7 for the roll
    Carbon: $8
    Plasic end caps: free.99 from recycling!

    So, $25 total for the filter, you can make it any scale really. Hope this gives you all some ideas, and maybe saves a few bucks and re-purposes some plastic jars along the way!

  15. Hey Scoobie! I was wondering about the PC fans as well. I've lightly browsed the topic of wiring them up to cell phone chargers and such, but never got the full understanding of the correct voltage chargers to use and such.

    If anyone can elaborate on this, I would greatly appreciate it. Maybe just post a thread that I overlooked.

  16. Most cell phone chargers are usually lower than 12 volts, actually. If you want your 12v fan to run at capacity, you'll need a 12v adapter. Usually, theyre either laptop or CD player power sources. Maybe your computer speakers use one that would work. You're looking for something that will generate more DC power than your fan will draw. Usually the PC style fans will stay in the .2-.7 amp range, unless they're ultra high or low-rpm units. Most old laptop chargers, for instance, run 12v at 2amps or so. That would give you headroom for 3 powerful PC fans, or more than half a dozen lower speed units.

    Hope that puts it in perspective, Chuck.
  17. Me & you are talking in 3 places right now! Haha, thank you for clearing that up. My knowledge of electronics is very minimal.

    I feel as if I went to and read up a little on electricty I would understand that 100%. So that's what I'm gonna do after I pack this bowl.

    Thank you again Scoob,

  18. Ok. After reading I fully understand now. The best power cord I could find is 9V DC 800mA. I have no idea what the 800mA is. Some enlightenment on the "mA" abbreviation and I'll have this whole thing down.

  19. Well, we're good GC blades, one topic per thread!

    Learn all you can, man. My knowledge was extremely minimal 3 months ago, this new hobby of mine has taught me a thing or two (now I'm up to moderately clueless). It seems, to be truly well rounded DIY growers, we've got to be real renaissance men: carpentry, electrical engineering, thermodynamics, and the art of stealth... And that's just a bit of prep work!

    Glad to help with what I can, I know that I still have a lot to know. :eek:

  20. milliAmp

    800 = .8 Amperes

Share This Page