can I make a carbon filter? I've found small containers of activated coal for aquariums at walmart. could this be made into an exhaust filter?

what about small electronic air filters. how well do they work with the smell? the air filter I have has an ionizer in it as well. what if I place the filter in
a buffer box inside the exhaust?

how well would these 2 methods work for a 4x10 room? what if I use both methods together? I've been researching and brain storming, but hearing from someone with experience can be invaluable.

Carbon filters are definitely the way to go. Lots of different styles. I just built a new one made out of an old dresser. Just the top drawer with the bottom cut out and a furnace filter in the bottom of the drawer and then put in a couple inches of carbon. Have an inline 6" fan plumbed through the top of it.

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very nice idea. how well does it work for you? do you recommend pulling air up into the carbon or down into it? how long does it last before it needs changing? what actually happens when the carbon is "spent". does it just not absorb any more oders and lets them pass back out of the filter?

Yes, build this Coffee Can Filter

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or you can build one of these...built it for 56 bucks from lowes....just lined the inside of the top with carbon filter material and taped it on...I also just threw the rest of the filter on the back of my box fan...the fan pulling air in holds the filter to the back and draws ait thru it...pretty damn simple...and it also works...

materials BTW:

50cfm bath fan
5"x4" reducer
4"x3" reducer
5" universal cap
filter
duct tape
extension cord

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I've looked around the forum and read up on different custom designs of carbon filters. here is what I've come up with in my own design:

1. I first built a small box out of 1x6 wood I had laying around. I mitered the corners and glued/nailed everything to seal it air tight. I end up with a box with no top or bottom, 12 inches long, 6 inches wide, and about 5 inches deep.

that's as far as I got so far, but here is what I have planned:

2. I take a standard air filter from a furnace or central air system. any will do, (can't be fiberglass type) but I'm looking for one with good air flow. it's a cloth-like filter with a zig zag shaped screen under it. flatten out the filter/screen and make it a flat sheet shape. cut out a piece to fit the box. fold the edges around to the sides of the box and securely glue and staple the filter to the bottom and sides of the box.

3. fill the filter with activated coal. I'm using coal from the aquarium section of walmart. spread out the coal evenly to cover the bottom of the box with an inch or 2.

4. I'll be building a custom exhaust filter to set my filter ontop of and seal it with weather stripping.

I've heard, once the coal wares out, it can be used longer by crushing the coal into smaller pieces, or bake it in an oven at 350F for 30 minutes. I'll also be using an ion filter to supplement my carbon filter. I'll post pictures when I finish it

to start with you cant use aquarium charcoal. it dosen`t hold the smell properly, has to be for air. the holes in aquarium charcoal is meant for a larger size particle and only last about 1 week.

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what about crushing and/or baking? or is there anything else that might help it work better?

any idea what they do to aquarium coal that's different from air filter coal?

they dont do anything. the way activated carbon works is that there is microscopic holes in the pieces that contain the smells or particles. the stuff you need has more holes per square inch and are smaller, so it holds more smells. the stuff for water has larger holes so the small smell particles go right through.
i made a homemade filter and made that mistake and it only lasted a week.

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Dutch Treat/12/12 cfl
Dutch Treat Time Laps Video

thanks for the info

I have all the parts to finish the project, and it only cost me about $5, so I'll finish the project and give it a try anyway. don't have anything to lose. the area my exhaust will probably vent into has a very dirty smell, so that will help cover up any spell that does pass through the filter. I think my goal with the carbon filter and the ion filter is to have it working "well enough". if it fails, I'll be in search of better carbon.