cph's DIY air filter...

I knew I wouldn't be able to spend a lot of money on odor control, even though I really need it. So I put this together at work and wanted to get some opinions. I think it will work but have a few questions.

It's made of 1/8" thick steel fully welded from the inside. I also leak tested it, not because I thought an air leak would hurt anything but to make sure my seldom used welding skills are still there. It is 12-1/2" x 12" x 20". With (2) 5" inlets and (1) 6" outlet. The out may need to get bigger but right know I have a 6" fan so thats what it is. There are 2 ins because I plan on having (2) 600w lights in the future with some DIY air cooled hoods. I bought the filters you see in the pic, I got 2 and plan on cutting them in half so there are 4 layers of filter. The side is removable for access to change the filters, I have rubber seals to put around the edge to help with leaks. You can see the hooks to hang it from my ceiling. I plan on finishing it tomorrow and painting it.

Know for my questions...

1. Do you think it will work?

2. Is that to much filter?

3. How should I space them? I thought it would help air flow to have them 3" apart instead of all together like 1 thick filter.

If you have any comments or suggestions I would love to hear them.

Light cooling isn't supposed to run through filters, it should be isolated from plant air..

born2killspam said:

Light cooling isn't supposed to run through filters, it should be isolated from plant air..

Click to expand...

Thanks for the input. I do plan on this air exhausting from the room. I do realize cooling the lights with it will probably get the filters to hot. I don't really need to vent the lights any way and this sucking air out should provide with enough cooling. I'm waiting for the glue to dry on the seal and I'm done with the filter but still need to finish hooking up the fan and tubes.

Here are the finished pics. Tomorrow after the glue is good and dry I will be hanging it and setting up the fan.

I finished and hung up the filter. It works pretty good. You can only smell it every once in awhile. I need a stronger fan to make it work properly. I thought 280 cfm would do more. Oh well, it will probably turn into my intake. I have 1 hose sucking in the grow area, and plugged off the other side. Here are some pics.

You don't want active intake, you want suitable exhaust and passive intake.. This will help prevent odour leaks because of the negative pressure created in the space..

Thanks agian. I will remember that. I guess that is why I was think a stronger fan, to get the negative pressure.

And sometimes you do need active intake, but not in many cases.. Only when the pressure gets too low and air exchange rates need to be higher.. But you will still want that negative pressure otherwise you'll get smelly air sneaking out via other routes without being filtered.. Even if the box is otherwise air-tight, odour can sneak back out the intake when positively pressurized..

Since you seem to have readily available metal working "stuff," why not make custom filters that you can fill/refill with activated carbon?

Perhaps two layers of steel mesh (small enough grid to hold the carbon) with either a metal or wood frame.

Know what I mean?

Anyway... carbon will scrub out smells much better than those filters you have.

diggitydank420 said:

Since you seem to have readily available metal working "stuff," why not make custom filters that you can fill/refill with activated carbon?

Perhaps two layers of steel mesh (small enough grid to hold the carbon) with either a metal or wood frame.

Know what I mean?

Anyway... carbon will scrub out smells much better than those filters you have.

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Thanks for the suggestion. I did look at different ideas as I put this together. For the 2 filters I paid $20. I couldn't find active carbon cheap enough for my liking. The filters do have active carbon in them, and there is no smell coming out the exhaust.

EBay for bulk carbon.. Gotta agree fully with the design critique though..

How much carbon do you think I would need? It's not that bad on ebay, I don't know why I don't look for more stuff on there.

Just grab a good deal.. It will likely be alot, but that shit is good for alot of things from moonshine cleanup, to poisoning control..

I'm sure this would be plenty for your application. 3.5L for 18.99

http://www.petsmart.com/product/index.jsp?productId=2754012&utm_source=googleproduct&utm_campaign=2754012&utm_medium=cse&mr:trackingCode=3AD4D151-4519-DE11-B0EA-001422107090&mr:referralID=NA#prodTab1

diggitydank420 said:

I'm sure this would be plenty for your application. 3.5L for 18.99

http://www.petsmart.com/product/index.jsp?productId=2754012&utm_source=googleproduct&utm_campaign=2754012&utm_medium=cse&mr:trackingCode=3AD4D151-4519-DE11-B0EA-001422107090&mr:referralID=NA#prodTab1

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Nice! Do you think pet stores would have that in stock? I'm going to check my local ones to find out.

Yah.. you can find that at pet stores. Look in the aquarium section.

I got some activated carbon. The local pet store had it for $24.95. Now I will be getting some screen and building a frame to hold it with.

born2kill you mentioned something about keeping the air from the light seperate from the air in the filter. Please excuse me if I sound stupid here but, how would I keep the smell from going thru the light vent? Can you please explain a little more?

Why not go with a proven design?? Screen kills alot more airflow than nylon stocking wrapped rat-wire, and in the case of nylon screen wrapping alone you'll end up with gaping channels to leak air unfiltered due to lack of rigidity pretty much however you try to stabilize it..
There is a reason proven designs are so much different than yours, and I'm guessing you NEED this to work.. Without proper engineering know-how you shouldn't try to design brakes for your car, and this is another safety critical situation..

Understood. I have no reason not to go with a traditional design. With what I thought I knew from reading around here, I didn't see why it wouldn't work. I was trying to stay cheap. I already have more $ in to the carbon than the rest of it, So i want to do it right. I tried looking for a DIY with what you are discribing and couldn't find a good one. I'll keep looking. Thanks for your help.

This is a decent one..
http://www.marijuanagrowing.eu/another-carbon-scrubber-design-can-filter-style-t8114.html

And Wolfman Zen's is a good similar design, but try to find baskets with as large of holes as possible.. Sending the air through the sides slows it down due 'through the carbon' meaning more cleansing contact.. Slower air is cleaner air but reduced airflow due to non carbon obstruction is counterproductive..