How to build a carbon filter on your own?!

green_nobody · 01-09-2008, 07:04 PM

Tools:
Fat flat head screw driver (For Clamp Tightening)
Scissors (Preferrably Tin Snips if you have them or some tough scissors)
Buy Wire cutters if you can, this is hard to cut through.

Parts:
Home Depot-
1 - 4" Duct Cap $2
1 - 6" Duct Cap $2
1 - 4" Duct Collar $4
1 - 6" Duct Reducer $6
2 - 4" Hose Clamps $2
2 - 6" Hose Clamps $2
1 - Roll Duct Tape $3

Small roll of coated steel square mesh (few sq. yards) - Firm preferrably. Not too stretchy. I used the stretchy soft stuff at first which works only if you pack the carbon in and use a lot of batting on the ends. It's ok but will sag. It doesn't keep its shape as well as the harder stuff. $6-$10

[Depending on how you will connect your fan, you may also want another reducer thats the same size of your fan and will connect to your reducer on the filter.]

Wallyworld-
Batting - Small Roll Blanket Style Not Clumped Preferrably $3
2 Pair Panty Hose (Clearance!) $2 I like using Queen sized Leggings much better. They won't rip as easy. Just thick Panty hose.
3 18oz Cartons of Super Activated Carbon *@ Pet Store Too $15
(Or do like me and buy in bulk online. I found a guy on eBay selling 10lbs. of carbon for $10. Can't beat that! Although shipping was like $8-10 too but still a smokin hot deal.)

To figure out the size filter you will need for your fan, use this formula:
[If you need a larger diameter filter than listed in the tutorial, then you need to upgrade the duct sizes in the list and update the instructions.] Also keep in mind that if you're running some ghetto fan, expect ghetto results. Spend some decent money on your fan and it will perform. Some cheaper fans will give inflated figures too as to what the true CFM ratings are. My sig has a link for great pricing on vortex fans. I'm using the 4" 175CFM.

D = Diamter of Filter Inner Core (Inches)
H = Filter's Height (Inches)
I = Inner Core Surface Area Square Inch

CFM D H I
150 4 9 113
200 4 12 151
275 6 12 226
375 6 16 302
400 6 24 603
550 8 24 603
650 10 24 754

See the relation there?
Just take the CFM of your fan and choose the diamater of core you want and divide it accordingly. For example: I have 175 CFM and intend to use a 4" Diameter core. So I can look at the list above and figure;
150(CFM) divide 9(H) = 16.6 (Approximately)
Then I can take my 175(CFM Fan) and divide it by 16.6 to get 10.5". Therefore, my 175 cfm fan with a 4" Diameter would need a core height of 10.5".

And so on... Just remember to be careful when your cutting the length of your core. It's important that the size is accurate or the filter won't work properly. If anything, you want to overshoot the height of your core by about a half inch at most. (I.e. I needed a 10.5" Height, so if there was a problem, I would want to make sure that my core is at least 10.5" to 11".) If you don't do this correctly you get a nice little backdraft and you filter nothing - like i did the hard way the first time. Filter the air - don't blow it around. Enjoy!

Ok step 1:
Take out your roll of steel mesh and measure the amount you will need. Make sure to use the formula above. Once you have the height of the core, just start snippin' away. I also like to use the same direction as the roll was in so it's easier to work with. [I have a 4" 175CFM Vortex fan so I built my filter core 10.5" Long.]

Step 2:
To measure the amount you will need, start rolling the piece you cut off around the 4" duct cap. Make sure to overlap by approximately 1-1.5". Or of course you can just measure it.

Step 3:
Once you have the size you need, go back and do one of two things. Either carefully snip off the long sharp edges or if you have a grinder, just grind them away. I have a grinder, but the snips were more accessible so I didn't bother. Here's a pic showing the difference. Get as close as you can - more details about this later.

Step 4:
Now make sure to have both the 4" duct collar, cap, and 4" hose clamps available.

Once you've smoothed out the mesh, begin wrapping it around the duct cap again and once you have it lined up straight, attach the 4" Hose clamp and tighten it down good. Make sure it's very tight, but don't get carried away and make it start bending. We want longevity, not overkill.

Step 5:
Now on to this little contraption which is going to be the core of our filter, add the 4" duct collar to the opposite end. Tighten the mesh and then attach the hose clamp just as it was done previously on the duct cap. You should end up with something that looks like the picture below.

Step 6:
Now unless your perfect, you likely ended up with this goofy looking part sticking out on the mesh. What I did is took some spare wire lying around (which you likely have too :joint

and stiched it down to the main piece. This is what it looked like when I was through.

Step 7:
Ok now open up a package of the leggings. We will be just cutting off the legs and the new 'socks' will act as a pre-filter. Depending on what type of leggings you got, you may or may not have a separate seam that attaches the panty part to the legs. If it's there, make sure to cut on the side of the panty and not the side of the legging. This will help ensure the end of the 'sock' doesn't unravel. Here are a couple examples for you:

Step 8:
Now we're going to make something that looks very familiar to most of us. A condom! No - kidding, but seriously I can't stop thinking that it looks like one. Take one of the socks from the open end and start rolling it. If you need help, please get in touch with the nearest female you know on how to do this. It's really not complicated.

green_nobody · 01-09-2008, 07:06 PM

Another version of that:

So you are having a problem with the marijuana odour and want to fix it so a priest can sit in the next room and not know you are the leading provider in your state for marijuana. Well its not going to work that good the home made jobs are not for the pro's but then again pro's can afford to go buy one

The Shopping List

1 roll - ¼” hardware cloth - look in the wire and fencing sections of home improvement stores
1 - 4” to 6” aluminum duct adapter
2 – 6” aluminum duct end caps (actually, you need a 4” and a 6”, but no one seems to carry a 4”, so I made one by carefully disassembling a 6” end cap cutting the end plate down to 4”, then re-assembling it.)
1 – 4” aluminum duct starter collar
2 – pair of womans pantyhose, I prefer black because activated carbon is black and it won’t look so crappy….it looks cool.
3 or 4 boxes – good quality activated carbon for fish tanks. (The actual amount you need depends on how big you make your filter.)
2 or 3 – 4” stainless duct clamps (those worm gear hose-type clamps- I used 3)
2 or 3 - 6” stainless duct clamps (those worm gear hose-type clamps – I used 3)
1 – tube of high strength duct sealant/epoxy - sets up strong and seals really well - usually found in the same section of the store as the ducting
a handful of batting material (cotton, etc – look in the quilting or fabric section at wal-mart, etc.)

Now for the Assembly

Disassemble a 6” end cap by drilling out the rivets. Cut the end plate down to a 4” circle with tin snips, etc. Wrap the edging back around the end plate and cut it to length leaving a bit of overlap. Clamp the two pieces together and seal with the sealant, allowing it to dry overnight. You should be left with something that looks exactly like the 6” end cap, but is only 4” in diameter.
Cut a piece of hardware cloth the length you want your filter and the appropriate width to wrap around the starter collar and end cap with a small bit of overlap. Wrap the hardware cloth around the end cap and starter collar and use a 4” hose clamp at the midpoint of the cloth to hold the 3 pieces together.
Cut a section of pantyhose to make a continuous tube, and pull it over the 3 pieces you just assembled. Add a hose clamp to each end to hold the pieces firmly together. You should be left with something that looks like a 4” version of the above pic with out the reducer, of course.
Insert the assembly you just made into the large end of the 4-6” reducer. It may take some force to get the starter collar to snap in properly, but it will. I then sealed the joint with sealant/epoxy.
Cut another piece of hardware cloth the proper length and size to go around the 6” end of the reducer and the 6” end cap, plus a little overlap. Install it with a 6” clamp at the midpoint.
Cut another tube of pantyhose and fit it over the outside of the unit. Be careful not to rip it or get a runner (heaven forbid!) Install the outer two hose clamps as in the pic.
Loosen the end hose clamp and you should be able to remove the 6” end cap without the thing falling apart at all. Add a few inches of batting material to the inside of the unit at the reducer end….this area will not have any airflow anyway and the batting will take the place of some activated carbon, thereby preventing wasted carbon.
Fill with carbon almost to the top, then top off with more batting.
Replace the end cap and tighten the hose clamp. Hook up to your duct work and enjoy the odor-less-ness!

The final product should look something like the picture below, sorry about the lack of step by step pics, but I do not need to make another one. One of these days I will get around to it.

Carbon Scrubber

This does work if you can follow directions if you can not follow the directions you should go door to door and ask people for money.

green_nobody · 01-09-2008, 07:26 PM

Security is important to marijuana growers, and odors can lead the police straight to your grow room. There are a number of 'odor solutions' out there, but they can be quite costly. Here is a simple method you can use to build your own carbon filter. It will take you about half an hour to construct it, and it will cost $20 to $30 dollars.

Aside from its main advantage of being ultra cheap, this method is also very versatile. It utilizes the exact same activated carbon filters that are used in professional air cleaners, without paying the huge prices. It can be adapted to practically any ventilation system. You do not need any crazy tools to build this - anyone can do it.

For supplies, everything is easily available at a store like Home Depot. You will need the following:

1 activated carbon filter - ( found near humidifiers, air, and hepa filters )
1 small roll of aluminum screen
1 four inch ventilation end-cap
1 four inch duct connector piece
1 roll of duct tape

No tools are required. A pair of scissors and a measuring tape are all you need.

The carbon filter I purchased is a 'universal' replacement filter for HoneyWell air purifiers. Since I didn't pay the hefty price for a professional unit, I will cut this to size. It was originally 16" high and about 48" long, so I cut it right down the middle. When the first filter is expired, I will have a replacement ready to go.

The next step is to cut your aluminum screen to size. I chose aluminum because it will be strong, and will still allow good air-flow. You could substitute chicken mesh or something similar. Since my (cut) carbon filter is 8" high, the aluminum will be cut to 12". The carbon filter will go in the middle 8" of this screen, with 2" coming out of each end to connect to the duct pieces.

Now we will attach the aluminum screen to the duct pieces, with duct tape. (This might be the first time you have actually used duct tape on ducts!) Do your best to keep it straight as possible.

It will seem a bit flimsy at the beginning. Continue to wrap the aluminum screen around and around, taping it every few inches. You want it to hold firm.

After a few wraps it will be fairly sturdy, and able to hold its own weight. However, don't drive your truck over it! Treat her nice and gentle like a Christian schoolgirl.

The ends of your screen may have little strands of metal poking out, threatening to impale you. Add some more duct tape to cover this up and to finalize the DIY carbon filter. Soon it will be done.

Now it is time to wrap the activated carbon filter onto our device. Conveniently, the filter I bought came with a couple of velcro straps, so I used them to hold it on. This will be convenient to replace when the activated carbon is expired.

After she's all sealed up, throw on a bit more duct tape around the edges of the carbon filter, to seal up any gaps. Only tape over the edges, because you want the air to flow as easily as possible. Air does not flow through duct tape. Here is the finished product.

Time to hook her up to the grow room exhaust! In this case, it is being hooked to a 4" square duct. (That is why I used a 4" round to 4" square connector piece. You may need a different piece to suit your ventilation setup, but a million sizes are available.) Just slide her onto the vent, and tape it down nice and sturdy. Duct tape is your reliable grey friend.

After she is attached and fire up, things are looking good. It is working nice, hooked to a 60 CFM fan, and you can feel the air flowing out of it lightly. The fan was not slowed down too much, but obviously a carbon filter will add some back-pressure to your vents. I haven't tried this with a slower blower (under 60 CFM), but 60 CFM is not a lot.

I just hooked this up today, so I don't know how often I will have to replace the carbon filter. The box the filter came in says to replace every two or three months. It does seem to make a difference though. Outside the grow room does not stink like a skunk anymore. There is almost no smell at all, except the faint odor of duct tape adhesive. I'm sure that will go away after a few hours.

Using this method, everyone can now build their own activated carbon filter. Its quite easy, and you can build it any size you need, to fit any grow room and any type of duct. Could it get any better than that?

green_nobody · 01-09-2008, 08:01 PM

Pet shop version:

1. Marineland Bonded Filter Pad (this shit is overpriced at Petco and Petsmart - about $5 for 312 sq. inches but it holds the carbon perfectly) Marineland Bonded Filter Pads at PETCO

2. Filter Floss / Filter Fiber (about $2) Petcetera Filter Fiber at PETCO

3.Activated Carbon - I got the 14 oz. and it will last for a very long time ($7.97) Aquarium Pharmaceuticals Activated Filter Carbon for Fresh and Saltwater Aquariums at PETCO

That's all you'll need!!

1) - Grind up a nice sized pile of the activated carbon. They are usually in pellet or pebble form, but in order to expose as much of it to the air as possible, you'll want to grind it into a granular, even powder, consistency. I used a spare coffee grinder I had laying around and it was perfect. If you don't have a coffee grinder, you could do this by grinding it between 2 bricks or stones (mortar and pestel style like the native Americans used for corn)

2) - Cut a circular piece of the bonded filter pad to be about 1" in diameter LARGER than your duct line. The bonded filter is actually 2 types of material bonded together, one blue and one white. Take several healthy pinches of the ground carbon and generously sprinkle into the BLUE side of the pad. Work it into the pad by tapping, shaking, twisting etc. Keep adding carbon until you feel it's loaded up. Gently tap excess out, but make sure it retains the majority of it. It holds it well.

3) - Take a good sized gob of white filter floss (which is just spun, white nylon) out of its bag. You'll want enough to fill about 6 - 10 inches of your duct line. Take that gob and roll it in the remaining pile of your ground carbon. Make sure you get it nice and "dirty" with carbon dust and particles. The floss doesn't hold as well as the blue pad, but if you work it in, it gets nice and dirty with carbon.

4) - Take the circular piece of loaded up Blue filter pad and carefully plave it in your duct line, with the blue side facing "in" and white facing "outgoing". If you cut the extra inch like I mentioned, you will kind of have to scrunch it into place. Place it far enough in that you'll be able to put the filter floss in after the blue piece is secured.

5) - Take the dirty filter floss gob and stuff it into the duct line so it just leaves you enough room to re-secure your line to wherever you're exhausting from (reflector, grow box, etc.)

That's it, you're good to go!!

ONE IMPORTANT NOTE: Depending on the power and suction of your exhaust fan, you'll want to make sure the pad/floss don't get sucked into your fan. This can easily be achieved by running several pieces of fishing line through the blue filter pad with a needle and thread, then the tag ends can be run up and out and secured by your hose clamp. if you don't have those, use several interlinked zip-ties that will work too.

Hobo · 01-10-2008, 01:15 AM

damn green, great posts.

DieAbetic · 01-10-2008, 02:53 PM

excellent. exactly what i was looking for!

tokecrazy · 01-10-2008, 10:28 PM

Way to go Green,Good post on how and all you need to build a filter.PEACE

green_nobody · 01-11-2008, 07:13 AM

Quote:

Originally Posted by DieAbetic

excellent. exactly what i was looking for!

good to know, than that problem is taken care off

smokedoja · 01-13-2008, 02:50 PM

Heres one I just built today! I used Silica Gel Kitty litter though...

PICT0566.JPG

SHAMAN · 01-13-2008, 03:09 PM

Quote:

Originally Posted by smokedoja

Heres one I just built today! I used Silica Gel Kitty litter though...

Attachment 5772

Nice!! Would love to hear how good it works.

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