homemade carbon filters?

W

wufo

New Member
Hi, Im new so I don't know if this post is in the right place or if this is an echo of the same old post.
I'm looking into making my own filters because I have no money literally, how do I know what size to make it to match the fan or is it all guess work, I'm looking for something sufficient in a 10x6x3 feet. With a 4 inch intake and a 5 inch out take.
Any advice would be appreciated or a link. I have one more question would a 5 inch pipe by say 12 inch long filled with activated carbon fitted to an online fan not work, is there a reason It has to be the shape and design of shop bought ones.
Thanks and by the way I've gotta take my hat off to some of u guys and girls on your set ups and creativity.
 
The ones you buy at stores are simply a, perhaps, more efficient design, but as long as the air goes through the charcoal before being vented out it should work. However store bought filters are not really that expensive, you should look into how much the actual difference is going to be, you may even end up paying more by building your own and you'll probably not get as much as a good result.
Here things are expensive, I bough a $60 filter and I've been using it for about 8 months and it still works perf3ctly, so overall it is not a big investment
 
I totally appreciate what you said, its just that I have my hands on some activated carbon and I'm an engineer so I can make the rest at work for free I was looking at making a tube with a screw on cap at both ends that will compress the carbon as I screw the caps in. I just wanted to make sure it could handle the amount of air passing thru, i.e being too small for my fans, thanks mate.
 
Ok I will try to add my diy 2cents. Bear with me here. You can make the filter any shape you want. Round just makes the air bend less.
Now you said your room is 10'x6'x3' That will need about 400 cfm to clear 5 times a min. So if you got a fan that's a good start.
Now I you have some wood laying around let say 1"x2" 1/2"thick. Cut eight 2 1/2 feet long
then cut two 6" and two at 5". now put them together to make a rectangle making sure you put the 5" on the inside to make a 6" square . Now cut two a flat board 5"x5". Now cut a 4" hole in the middle of one of them and then slide them inside the 6"x6" rectangle and attach and seal. Take a window screen or some kind of screen that the carbon can not go thew and attach to rectangle all the way around and seal on the ends.
Now thats the inside.
Now cut two at 8" and two at 7"
Now use four of the 2 1/2 feet long boards you have from the eight you cut and make a rectangle with them.
Now find two boards to cut that will be 8"x8" square to put on each end.
Attach one of the 8"x8" board to the first 6" rectangle and make sure it is centered in 8" end cap boards.
Now slide over the 8" rectangle over the 6" rectangle and attach it to the end cap.
Now get the same screen you used on the 6" rectangle and rap around the 8" and seal it on the end cap that's holding it all together.
Now on the last end cap that is not on yet cut a 4" hole in it right in the middle.
Now stand the filter with the end cap on the ground and pour your carbon in between the 6" and 8" rectangles. then put cap on and make sure the 4" lines up with the 4" hole in the middle attach to both rectangles and attach and seal the screen to the cap. Now if you got a cotton soft sheet rap around one time to cover screen and attach you 4" exhaust line to 4"hole and there you go..... sorry about the pic lmao
Carbon_filter.png
 
This should help I hope: DIY Can-Filter

As far as filter size goes, afaik, it only affects filter life .. not effectiveness. I could be wrong tho, kinda new but I've been reading tons of sites and advice and been bussy distilling the ' truth' out of them ..or at least, trying to :p
 
Hi thanks for the link that's a good read, what cmf would that fan handle, and was it two foot long?
 
Fan ? I guess you mean carbon filter ? In that case, to my understanding, any that you can couple on the 6" end without starting to build up too much pressure as that cancels out the negative pressure thing you want in order to prevent smell leaks .. no clue on numbers tho .. the higher the cfm, the more airflow, and thus need for longer fliter or wider filters or multiple filters. You'd best have your filter too large, as too much buildup of pressure will cause more draw on the fan and possibly shorten it's life.

My guess is that the hardwarecloth's width becomes the length of the filter, in which case that width would indeed be 2 foot long. This because the 6" and 8" diameters * 3.14 results in ~19" and ~25" for a combined length of 44" devided by 12 = 3.6 foot and we needed a bit or a lot of overlap to strenghten the construction. So in order to build it with the stated materials, you'd get to 2 foot lenght for this example.

Mine will be 4" inner and 6" outer .. as I dont need to move a lot of air in my small growspace.

Again, I'm a n00b .. and I also didnt create that DIY howto .. I just searched for it using the search function and pasted the link ;)
 
i'll take some pictures tonight, I also went the diy on the filters, bought 50lbs of activated carbon-ebay(1$ per lbs) made 3 filters,biggest is 3 foot long, all have lasted me 3 years running everyday.

I do tear them down,every 6 months and "wash" the carbon, let it cook/bake in the sun for an afternoon, reassemble and back into service
 
Hi cheers for the info, I did mean fan...just didn't wanna use a 200cmf fan if the filter could only handle 100 for example. I just don't wanna waste time building it for it not to work thanks for all the input. :)
 
I dunno what kinda fan you mean there .. I see none mentioned in either the filter DIY or this topic .. mine is a 10cm 100m3/h inline fan, made of plastic, and not moving all that much air .. it's slightly under recomended cfm but seems to work well .. any higher would deffinately require a humidifier here.

My grow area is 62x62x122 cm's.
 
The fan has to be powerful enuf to pass air thru the filter but not powerfull enuf to pass thru the filter too quickly is what I meant I didn't want to make a filter that was too weak for the required fan for my specific area is all I meant, cheers for the input keep it a comin.
 
wufo said:
The fan has to be powerful enuf to pass air thru the filter but not powerfull enuf to pass thru the filter too quickly is what I meant I didn't want to make a filter that was too weak for the required fan for my specific area is all I meant, cheers for the input keep it a comin.
Click to expand...

The more surface area you have in the filter, the easyer your fan will be able to move air through it. So either making it longer or widwr will accomplish easyer passthrough of air ... you cant really make it too large until it becomes unpractical ;)
 
I have a ultra stealth grow cabinet I recently put together. I'm a pretty crafty type (mechanic by trade), and as cheap as they come. I spent a lot of time making a carbon filter for my grow and in retrospect I would NOT do it again. It would be much easier, wiser, and neater to purchase a descent commercial filter, then dissect it when the carbon needs to be replaced. The filters by design are simple enough but getting everything to fit together, not leak, and be serviceable can be a challenge. I'm usually the guy that encourages DIY but this is one item where the price isn't too outrageous for the product offered.
 
All that requires powertools that are expensive and not in everyones garage. I don't see how spending over $ 50,- on a new filter in the hopes of succesfully taking it apart later and further hopes of getting it back together and in working condition, outweighs $ 15,- on DIY materials using the same concept and next to no tools ?

Sure, if you have the skills and equipment, it does .. but I have screwdrivers, a hammer, a cutter, and a drill. As much as I'd love to do as you suggest, I'll have to do with what I have .. as there is no budget for buying the tools needed to carry it out ;) And I know all I need is that hammer and Ducttape, but meh ;)
 
Is really like to see your DIY filter, I have a full machine shop at my disposal I was thinking of making a pipe filter maybe going from four inch coning up to five inch to help to dispose the air more quickly and to create a semi suction kinda effect, with a mesh bottom and a mesh screw on cap that compresses the carbon as I tighten it, if it works it will be an easy working/ easy refillable filter. Thanks for all the responses.
 
ColoradoHigh said:
My carbon filter/fan combo is designed so that it is refillable, no disection required, it was one of the main reasons I went with this particular unit.
Click to expand...

Can you share it ? Cuz that sounds like a very good option to me .. if affordable ..
 

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