MacGyver carbon filter? (DIY)

I got this activated carbon:
http://www.walmart.com/ip/AquaTech-Carbon-Fish-Aquatic-Pets/10313138

..and I'm trying to figure out how to best make a filter with it. I have seen using cups like this:
http://www.walmart.com/ip/Rolodex-Nestable-Jumbo-Wire-Mesh-Pencil-Cup-Black/14916659

..and putting two together and the carbon in between, but of course finding the exact fit for your duct size is almost impossible. My duct is 6 inches wide, and I know a lot of you have made DIY carbon filters before so what are some good ideas? Anything and everything is good remember this is a MacGyver thread!

Use an new vacuum cleaner bag, make a pillow slam to duct, change 2x times per year .....done!

vostok said:

Use an new vacuum cleaner bag, make a pillow slam to duct, change 2x times per year .....done!

Click to expand...

I don't quite get what you're saying. where does the carbon fit in? What do you mean by "make a pillow slam to duct"? Are you saying put the carbon in the vacuum bag and seal it on the end of the duct? That's a pretty good idea, but how to seal the bag on the duct? And it seem like that kind of bag would block a lot of air.

not worth your time and money to make your own filter, the thing you cant do is pack the carbon as tight as RHINO AND CAN do.

well good carbon filters cost 50+ USD am I right? I'm looking at less than 20. That's not really the issue per say, I just don't need a big ass rhino on the end of my duct. Maybe I should get a refillable Can filter and stick it in my duct, but I really don't think that's necessary. All I really need is something that will hold the activated carbon and attach to the duct and allow air flow.

Come on, I know a lot of people have used improvised carbon filters before, what's up!?

Im sure someone out there is making homemade fans out of a tin can and a hairdryer motor and another blowing hps bulbs from old coke bottles but seriously lets get a life and focus on growing pot.