Trying to calculate my filtersize for my mini grow

[Doji!]

so, I've been reading a few guides on the DIY scrubbers and found a nice bit of math to help me calculate my filter size in the the [FONT=Arial, Helvetica, sans-serif]DIY - Build a Carbon Scrubber For Dummies![/FONT] thread

but its been quite a while for me since I've been used math like this, and with the whole conversion of inches to cm/mm is just giving me a head ache

im hoping someone can help me with the math side so i can figure out what size the filter core should be for the fan ill be using.. , and whether or not the things I'm planning, are possible or not..

i have made the following assumption:

a 100-120 mm PC fan should be good enough to handle the content of my big tower PC case

now I'm trying to figure out the size of the core for the filter on it..

the inner core should have a diameter of 100 mm, the outer should be 150 mm, leaving 25 mm ( roughly an inch ) for the carbon

witch leaves me with how long it should be..

the fan ill be using is This one..

It moves 95 m³/h or 1.58 m³/m

1.58m³ = 55.79 sq ft

so if i understand things correctly, the fan has a CFM of 55.79




According to the scrubber for dummies,

[FONT=Arial, Helvetica, sans-serif]

[/FONT]One inch = 25.4 mm

[FONT=Arial, Helvetica, sans-serif][FONT=Arial, Helvetica, sans-serif]D = Diameter 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[/FONT]

See the relation there?
Just take the CFM of your fan and choose the diameter 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[/FONT][FONT=Arial, Helvetica, sans-serif][/FONT][FONT=Arial, Helvetica, sans-serif] fan with a 4" Diameter would need a core height of 10.5".[/FONT]

in this bit of math, i cant seem to understand what the 16.6 has to do with anything, or what it relates to..

i think this should be correct.. but since I'm lacking understanding of what the 16.6 has to do with it its still basically a guess

my fan CFM:

55.79 / 16.6 = 3.3608

so if i use the 120 mm fan, with a 4 inch core, the core should be 3.36 inches high, or more familiar to me, my core would end up being 100 mm wide, and 85.36 mm high

Can anyone confirm this? or confirm the fact i should have payed better attention in class

 

[Doji!]

hmm, i now made the realization there's a difference between the fan diameter and the core's

i should not try maths at 5 am after a night shift..

Is there a problem if the piping from fan to filter goes from 120 to 100? or does only the relation CFM to core size matter on this?

 

[tube dude]

I Don't think it really matters. My filter is flat and it works just fine.

 

[Doji!]

Ive been thinking of a square filter instead of the round one, ( can mod one of the bay drives to fit one ) but im still not sure if it matters if the filter is " to big "

DurbanPoison warned about making the core to small, but wasn't sure if any problems would occur if its to big.

i have seen quite a few people DIY a scrubber without ever mentioning their fan
so still not sure about it.

tomorrow ill be picking up the big tower PC case so i can start figuring out the exact space i have to fit the filter

 

[Kush Technician]

It wont matter as long as you can get good air flow through. Rig up several designs since this is a relatively small component, scale-wise, and see what you like the best. I'd go with some sort of tray that has air passing through it and can be fit into one of drive bays as you mentioned. For a pc case you wont need much carbon at all. And come to think of it, unless really properly utilized, carbon filters do not solve the problem of smell. A PC case grow will not produce enough smell to worry about. You would have to worry more about light leaks and the fact that it is a PC that makes a humming noise, yet doesnt appear to function as a proper computer should.

 

[Doji!]

i am yet to convince my spouse to put me some canna in it, but for now, its for a tomato grow

 

[Doji!]

i understand that there will not be much smell, but i will be trying some of the more .. fragrant ones, like cheese

and i really cannot afford any smells to drift around my apartment as i have a lot of passers by on their way out so i just don't want to risk it.

Better safe then sorry

This will be the tower ill be picking up

i will be cutting some of the metal work away to open the inside up a little

but im planning for the filter to be in the top 2-3 spaces of the drive bay

removing the disk and the HDD bay,
and cutting the metal plating that separates the 2 compartments

 

[Kush Technician]

You plan on smoking the bud in the apartment, yes? And you plan on having the bud in storage in the apartment? How about drying the bud? How about come trimming time? It's going to smell no matter what. If you are in a bad place to grow, you should probably get a big filter and just scrub the entire apartment air at the critical times when you will be making more smell, like late flower-trimming- I mean if smell is really an issue that is.

PS I like the PC case idea though and see the potential for you to crank out some killer nugget

 

[Doji!]

Im from holland, The smell of smoked weed is not an isseu.. the smell i fear from the grow is what bothers me, as i have no space but one close to the hallway

 

[Kush Technician]

well if you are in Holland I am confused, because isn't it decriminalized to grow small personal amounts of like 5 plants or something? Sorry I guess I will go do some reading now, heheheh!

 

[Doji!]

I'm more then happy to clarify this as best as i can.

Its legal to have up to 5 indeed, but its all a very big grey area..
if i put them in my backyard and just let it grow... no problem.

but as soon as i add lighting, its illegal.

Tho if someone smells your grow in the BY and reports you, police will drop by, and you will be told to remove them.
This has happened to several growers in my surroundings.

I am lucky enough that as long as i puff puff pass with my moms
neighbors after i harvest, they don't mind ( using her backyard since i have none )
so i have not yet experienced this 1st hand

but because its far from my house, i have not enough time to take care of them like i should and want to.

also, in my rental agreement states that i am not allowed to grow, so that adds another reason for stealth

the cannabis that you get from the apothecary here is just **** ..
its all supplied by 1 company, that only produces 3 types.

and none of those 3 help me with my issues. so i am forced to buy from the shops.
( hardly no insurance companies refund the cannabis treatment,
so i still end up paying roughly the same price as it costs in the local shop here )

 

[tube dude]

Small plants smell just as bad as large plants. you can have a lot of smell coming from a small cab. I run 2 fans in my cab.One to cool the lights and one to scrub the grow area

 

[Kush Technician]

Just having the bud in your place is going to make it smell, won't it? You might scrub the entire apartment air to be safe because it sounds like you really can't have any smell leaking out. Use negative pressure in your apartment from pulling the stank air through the filter and out the window. Or just have it recirculating the air in the place, but this is not the correct way to use carbon filters.

My point being that if you are concerned with smell, having the PC case air filtered is good, but won't it still smell like weed inside your apartment by the fact that you will be housing freshly harvested and cured weed in potential perpetuity? I agree that even a small plant will smell, but even a small nug will smell, possibly even more than the plants.

So ironic that Holland would be a risky place to grow. I never would have thought it so. Good luck with the build.

 

[Doji!]

yeah, I've been looking into this, and am starting to find our laws falling behind on the rest of the world.. id love to get a legalized growing permit, even if it was for only 1 plant.

if i could do it all legal, it would be so easier to set up for a single girl

as for drying , i plan to start off with just 1 plant, and see how many i can fit in the space left over.

my outside grows i have usually dried in the room i plan to grow in, but it was never primo stuff and the smell was not that bad, and air freshener in the hallway covered it all up, and that was about 500 grams

but i do see your point. but I've never had complaint from my neighbor about the smell in the hallway, even tho i smoke on my way in and out.

basically what I'm afraid of someone being able to differ between the smell of smoked and fresh weed and would like to eliminate this from happening.. I'm sure the drying will also cause a smell, but am planning on a 2nd PC case with another scrubber for once i need to dry the stuff

( am a big hobbyist of PC's. A few more or less cases wont be noticeable in that room for passers by )

 

[Kush Technician]

not talking about the smell of smoke, but the smell of the herb sitting in a container. My cured herb makes the entire place reek. It smells the same as the flowering plants, only stronger.

 

[Kush Technician]

In fact we as consumers of cannabis don't even realize it, but to others who don't partake, they can smell the herb on us. Being in the same room with it long enough will dull your senses to it.

 

[Doji!]

so, i've given it some thought, trying to think of various ways to place a scrubber

the best option i was able to come up with, was to use the actual cd rom drive as i have several old pieces of junk lying around



This is the drive emptied out, and it came with a convenient hole on top that i might be able to use as outlet to my fan

not sure how ill end up doing it, as i might even add another drive to increase the working size, and maybe make it a little less cramped

but i did step off the idea of a cylinder shaped filter

On Another topic, I'm going to need to seal a lot of holes in this case, but i have adhesive foil for the bigger plating that makes it a little easier

front panel closed up with foil


but for the corners and such, ill need something else.

i was thinking of using this:
http://www.bison.nl/nl-nl/producten...t/1715-super-sealer-construction/information/
( i hope the brand is known outside of Holland )

Or just use a silicone based " patina " ( according to the translator i used.. that should be the product name I'm thinking of )
http://www.bison.nl/nl-nl/producten/660-siliconenkitten/product/618-siliconenkit-sanitair/


but i've read quite a few things about gasses coming from products and/or materials used

I assume that if i let it sit for a few weeks before using the box, any nasty gasses( if present ) will have evaporated?