Facts to build DIY Carbon filter

[WashougalWonder]

Well I have been all over the internet looking, got some good ideas, but not able to find any data (other than the below quote) to determine sizes for CFM.

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".

[I found this formula somewhere online I can't remember. It's legit though.]

Well my fan is 750 cfm vortex. My calcs using the above formula show a length of 32 inches. I question if that is enough without blocking air flow. Sure could use some info from a person that knows this stuff.

I am figuring an inside diameter of 8" and outside diameter of 10"....will that be enough to scrub the most of the odor without causing back pressure?

If folks have positive info, we could turn this into a good thread about how to calculate and make a DIY, as those out there are similar, but getting the right size is important to not cause other issues. There are few, all similar, but only the one I quoted from has info about calculating proper size.

Have a day folks. WW

WashougalWonder Reviewed by WashougalWonder on 01-27-2011. Facts to build DIY Carbon filter Well I have been all over the internet looking, got some good ideas, but not able to find any data (other than the below quote) to determine sizes for CFM. Well my fan is 750 cfm vortex. My calcs using the above formula show a length of 32 inches. I question if that is enough without blocking air flow. Sure could use some info from a person that knows this stuff. I am figuring an inside diameter of 8" and outside diameter of 10"....will that be enough to scrub the most of the odor Rating: 5

[bigsby]

If folks have positive info, we could turn this into a good thread about how to calculate and make a DIY, as those out there are similar, but getting the right size is important to not cause other issues. There are few, all similar, but only the one I quoted from has info about calculating proper size.

I love this fan stuff. I spent a ton of time researching the ins and outs of calculating fan needs. However, for the carbon filter I never considered DIY, in part due to need to get sizing right and in part due to the mess and hassle of DIY. And I DIY most of my home improvement needs. For this discussion it is important to note that the carbon that you use is important; good carbon is a must.

Note that you should not mess with carbon unless you have a well ventilated work space and a GOOD dust mask - not one of those quickie $1.50 masks but a proper, fine particulate respirator (plan to spend $50 on the mask). You do not want this stuff anywhere near your lungs. If it goes in it ain't coming back out...

I do understand the urge/need to DIY one of these. A good, long lasting scrubber is not cheap by any stretch.

[WashougalWonder]

I did a lot of research on this. Components to make, the type of carbon, how long it lasts, blah.

It is cheaper, the first time around to buy a commercial carbon filter. The cost is the carbon.

Now, carbon can be reactivated by reheating to over 400 for several hours. I hope to be able (and it looks like I can) when this one needs changing to disassemble and recycle the carbon and put it back together.

For now, it works, cuts down on noise too

[LetsSeeYa]

I did a lot of research on this. Components to make, the type of carbon, how long it lasts, blah.

It is cheaper, the first time around to buy a commercial carbon filter. The cost is the carbon.

Now, carbon can be reactivated by reheating to over 400 for several hours. I hope to be able (and it looks like I can) when this one needs changing to disassemble and recycle the carbon and put it back together.

For now, it works, cuts down on noise too

Hey WW did ya ever build one or your still running on good carbon? My tents getting stinky and im not in flower yet! So its going to be stinking bad im thinking




Thanks WW:rasta: