My $3 Carbon Filter

This is a fantastic idea! I really dont have the $80-100 to spend on a premade can filter and it would be a downright pain in the ass to hang up in a grow thats already running.

Im headed to the store tomorrow get the materials needed and tape a filter down to both sides of my exhaust fan to make sure it gets scrubbed twice. Ill double check all of my seals for the venting flaps to make sure no smell can get out.

Excellent guide! +Rep to OP

Following up with the results from my application from this method

Its a double edged sword, unless youre prepared with the right equipment. I use 2x 240CFM 6" intake and exhaust for my 4x8x6.5 hut, 208cuft. Without either a larger / higher capacity exhaust or a fan speed controller, you are going to have very high positive pressure which puts both the fans and the plants under strain. Not all fans work with fan speed controllers. I was glad I had amazon prime and overnighted a fan speed controller by hydrofarm. Lucky for me, my inline fans didnt have a power relay and its hard wired in to a grounded plug. Now that Im running my intake at ~60-70%, pressure seems stable.

Material cost from meijer was actually about $29 and they didnt have scotch brite cloths like that. Ive seen these types of cloths before used on food service equipment, they are actually more effective than actual linen and hand towels for light-medium cleaning purposes. I went to walmart and they had clorox handiwipes which are the same thing, different brand and color for an additional $3. It wasnt so bad to do, Ive done some stitching before. If you get thinner thread like I did, make sure you knot the ends really well or it will be pulling out of your eye quite a bit.

Reccomend securing finished filter on the outside of the duct rather than inside for better airflow and suction and less chance for catastrophic damage. The idea of a bag of black pellets going through my fan does not sound very appealing. It could potentiall break the fan, make a huge mess, and even start a fire. There has been SOME smell still in the air, I think it is residual from the length of time that its been unfiltered.

Total Cost: $32 for materials + $25 for duct controller = $57
Total Time from creation to installation: 2.5 hours. I wasnt medicated at all until after installation

Bottom line: If you have the time, necessary equipment, and the basic sewing skills to rig this filter up, go for it. These WILL work in a tight money pinch. The carbon filters with rated CFM speeds are a lot friendlier to use, and not all that much more expensive. They look a lot better, and are a lot safer to use too. Your best bet is to plan the cost of a filter thats pre-built into your budget if you are going to stealth grow.

how much odor will it get rid of and will it work like the 100 ones

So i was gonna try this, i have pc fans in my grow box tho. And although there are circular holes cut out around the fans where i could put sum ducting, im putting the box flush against the wall & dont want to. So i was wondering if these filters would be effective if I just duck taped them over the holes (without adding ducts)

Panhead this idea rocks! thanks from a fellow michigander

Form and function, and cheap to make. Excellent work.

very nice gonna have to give it a try...

I was going to use one of these 6" engine intake air filters, only $25 shipped on ebay, put a nylon inside, fill it with carbon, tie the end of the nylon and attach it to the inline fan, I would think you would get more life and be able to remove more odor out of this method and the only thing you would have to replace is the carbon, do you think the OP's idea would work better?