DIY Carbon Filter w/ Component list and instructions


In Bloom
This will be a breakdown/tear down of a DIY can style Carbon filter in reverse. The unit I will deconstruct is the first one I ever built and probably my favorite.
It worked fine for several years as a stand alone unit in an 6' x 8' grow area. It should be good enough for all but the largest tents and stinkiest of strains.

I only went to a Can brand when I was gifted a larger unit than my DIY. I always opt to replace the AC in all my filters when I start noticing loss of efficiency.
It's just too easy and so much less expensive to do so.

I will attempt to make it as simple as possible and am happy to answer any questions after I've completed my post.

Unfortunately, I've switched to Sat I-net and have almost reached my data limit for peak hour usage.
I will post, pics, instructions, parts list, and info after 2am my time, when I have much more free data to use.

Once I begin posting pics and info, please refrain from posting questions or comments until I can complete it, just to keep the fluidity of the DIY intact. I'll try to get 'er done as quickly as I can. Thanks :)

finished filter - Copy.jpg


In Bloom
Parts list:

6" Inner core:
1- 6" inch duct cap
1- 6" duct collar
1- 18" x 20" section 1/4-1/2" hardware cloth/chicken wire (46cm x 51cm)

8" Outer Housing
1- 8" inch duct cap
1- 8" to 6" duct reducer
1- 18" x 26" section of 1/4" or 1/2" inch hardware cloth/ chicken wire (46cm x 66cm)
1- 18" x 26" poly/nylon window screen (optional but helpful) (46cm x 66cm)

2- pair large panty hose
4- 8"-10" duct clamps
15 lbs. approx- activated carbon (granular in this unit)
duct tape/ aluminized tape
1- foam a/c window seal
1- pre-filter (not shown, but essential for longevity of filter)

Tools needed:
1- screwdriver or nut driver for clamps
1- side cutters, tin snips or wire cutters
1- measuring tape
1- scissors or razor knife to cut tape/nylon hose
1- pair of work gloves
1- pair safety glasses
Last edited:


In Bloom
Gather your tools and materials and begin by cutting your hardware cloth to desired size. Be careful as the hardware cloth leaves sharp edges.
Dry fit the inner core and outer housing to ensure proper fit. Tape the long seams or secure by your preferred method.

Assemble/secure the 6" inner core - 6" cap, wire mesh, and 6" duct collar (tabs up) and tighten the (2) clamps. (left)
Tape over any sharp edges and seams as needed.

Do Not securely assemble the outer housing at this time. Just make sure its a good fit, and remove the cap and reducer for now. (right)

#1 components dry fit - Copy.jpg


In Bloom
Carefully cut, stretch, and maneuver, one leg of the nylons/panty hose over the end cap and up the inner core until the wire mesh is covered to just above the clamp. Tape the hose at the top just above the clamp.
This used about half of one leg including the foot portion which is left on and covers the end cap. I'd suggest repeating with the other leg for a double layer.

Slip the 8 to 6 reducer over the collared end of the 6" core. Push the reducer until it fits securely and Tape the tabs on the collar to the inside of the 6" portion of reducer as shown.
Pic 1- example without nylon filter
Pic 2 - taped tabs on collar to inner 6" portion of reducer
Pic 3 - Foam inserted in between 8"end of reducer and 6" inner core/collar to stabilize, help compact carbon and seal/isolate the carbon bed between the mesh layers.

6 in. core with 8 to 6in. reducer - Copy.jpg #2 tape sealed tabs from 6 in duct collar to inner 8 to 6 reducer - Copy.jpg #3    6 in. core with 8 to 6in. reducer - Copy.JPG #8  foamac window seal - Copy.jpg


In Bloom
Slip the 8" outer wire mesh down over the core and secure it to the outside of the 8" inch portion of the reducer with a clamp.
I then covered the outer mesh with one layer of nylon/hose, one section of window screen, then 1 or 2 more layers of nylons/hose.
This is the tough part, Use the upper legs portions with both ends open. Try doing it like a woman might actually do, while putting on hose.
Roll each section up and stretch it out the best you can to get it to fit over the 8" mesh tube. Careful not to get a run...
The window screen layer is to add stability and prevent the carbon from bulging out of the mesh when you compress the carbon in the final step.
#4 outer housing in place.jpg #5  8in. outer housing with filtering  - Copy.jpg


In Bloom
Tape or zip tie the nylon/hose to the 8" portion of the reducer. Slide the second clamp over the now filtered 8 inch tube, an inch or so below the opening where you will fill the carbon and place the 8" cap.

I used small chunks of foam at the 12, 3, 6, and 9 o'clock positions, in between the two mesh layers to keep the inner core centered, top to bottom while filling. Now, slowly pour in your carbon. (Before using the carbon, granular or pellets, it is a good idea to place the carbon in a mesh, burlap or similar type bag. Take this outside and shake the hell out of it. Really mix and thrash it, trying to get as much of the dust out as possible.)

Fill it to a level almost even with the top of the 6" cap.
Shake gently but rapidly, and tap on the ground to settle the carbon. Get is as packed in as possible without blowing out the hose/nylon filter through the wire mesh core or outer housing.

Add more if needed to level, and insert the 8" cap. You can use the same foam inside the 8 inch cap to help create pressure and compact the carbon.
You should feel it mashing the foam into place as you insert the 8" cap.

Slide up the clamp, tighten, and secure the outer filtered wire mesh to the outside of the 8"cap.
Finish with tape to secure the nylon/hose filter material. Dont tape over the clamp yet!
Give the whole filter a shake and a turn. If you hear a lot of movement, you need to stand it back up, remove the 8" cap, and add more carbon.
You want it as tightly packed as possible.

Tip: Take this completed filter outside. Put your 6", or adapt an 8" inch fan on the 6" reducer. Face it inward and let 'er blow. Try to blow any residual dust outward instaed of sucking it into the fan.. 5-10 minutes should do.
Excess carbon dust has ruined many a high dollar fan IME. Live n learn ;)

This 6" to 8" inch filter has a 1" inch carbon bed. That is not very deep. This is why I used Granular Carbon in this particular build. It is more dense and packs tighter for a more thorough filtration. It worked quite well and I refilled it several times.
On a similar 6" to 10" inch filter I DIY'ed, I used 1/4 inch wire mesh and pelletized activated carbon.
The 1/4" mesh is more rigid and stable for the additional stress and weight of the carbon.
The 6" to 10" Inch version has a 2 inch carbon bed, more suited for pellets of activated carbon.

The cost of premade filters has gone way down. But often you get what you pay for with a shallow carbon bed that doesnt last or filter efficiently very long.
At the time of this original build, there were only 2 or 3 brands available. All of them over $150-250 USD for a comparable filter in weight and size.
I had all of the components on hand except the carbon. So the build was fairly inexpensive.

#6 Filled filter.jpg #7   8in. cap with .75 in. butyl seal - Copy.jpg complete filter - Copy.jpg


Staff member
Excellent write up and visuals @jpcyan2. Have you compared these with a cheapo like vivosun? I like how it's similar to prebuilt cans, it's refillable, and you can customize it to length if desired. All with stuff found at Blowes or Dome Hepot (except for the carbon and panythose :)) Good stuff, thanks for sharing this! πŸ‘ŠπŸ‘


In Bloom
This was initially built around 2006. I did, at one time, check out some of the lower priced pre fab filters of comparable weight and dimension. Both in store, and on-line. I had some info and a thread or two with weights, and CFM/sizing charts. This material was lost in board upgrades on another site. :(

I haven't used a DIY build in over ten years. I was gifted 3 much larger Can Brand filters by friends who thought they would rather buy new than replace the carbon. I gladly accepted and replaced the carbon for 1/3 the price of a new filter. They have since changed their tune and always replace the carbon as well :D
Thanks for the kind words :)
BTW, if you do go to buy pantyhose, and you consider yourself a bit of a sketchy looking fellowπŸ‘€ (like me). It may be a good idea to have the wife or gf make the purchase. :p
Here in fly over country.. a skinny, sketchy, long haired guy, buying large panty hose.. only a couple reasons most would think of for that. You either wearing 'em or using as a mask :LOL: . Neither is a rumor ya want floating around small town USA.

Peace brother glad to be back.


Staff member
Lmao πŸ˜‚πŸ˜‚πŸ˜‚ 10-4 good buddy. I used to have super long hair. Had to chop it to get a job I wanted. I've shamelessly bought panty hose for similar applications.

Sample Walmart Cart I had at one time or another:
- 4pk pantyhose
- assorted clamps, nuts, bolts
- 2x 5 gal buckets
- 12pk Mason jars
- jumbo pack paper towels
- iso alcohol
- hydrogen peroxide
- box of nitrile gloves
- chips n salsa
- diet coke
- mentos

You ever get that look like, "WTF this guy gonna do surgery or taxidermy while having a snack or some shit??"

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