- Activated carbon granules suitable for air scrubbing
- Wood to make a frame, e.g. 35x75mm pine
- Piece of MDF or plywood
- Fly screen mesh
- Fence mesh
- U-shaped nails
My design for a flat-panel carbon filter
is a flat panel carbon air filter that I made for about $30 (not
including carbon). Itís not as compact as a round filter but itís easy
to make and works perfectly.
This is just a frame to hold a bed
of carbon granules on flyscreen mesh, with the other side of the frame
sealed by MDF. My first idea was just to use fly screen on a wooden
frame, but the granules are heavier than youíd think (about 0.6kg/L).
So I used some rigid fencing mesh to support the fly screen.1)
Construct frame of required length and width from wood2)
Glue a piece of fly screen to one side of the frame3)
Nail a piece of fencing mesh over the top of the fly screen (U-shaped nails are good for this)4)
The other side is covered by a piece of MDF or plywood, which is screwed on so that it can be removed later5)
The fan or a duct starter can be mounted onto the MDF side. I covered
the hole with another piece of fly screen to keep the granules in, in
case I forget that it is open or I drop it.6)
Fill the frame with a layer of carbon and seal it up
fencing mesh prevents the fly screen from drooping. This would cause
all the granules to collect in the middle and leave a gap around the
edges. The fly screen is also glued to the frame at the edges to
prevent granules leaking out.
The fencing mesh is expensive at
about $80 for a huge sheet (1.2x2.4m), but you can substitute that for
something else. I found some in my backyard (no it wasnít a piece of my
what Iíve read most commercial filters use a 20-25mm thick bed of
carbon. The ideal bed thickness will depend on your fan, frame size and
required air flow. I just used 25mm bed thickness and that seemed to
work first go, leaving no smell but still giving good airflow even with
a 150mm axial fan.
Where do you get activated carbon and how much does it cost?
are many grades depending on what you are trying to filter. I bought
carbon specifically for odor filtering (specification Ď4x8 mesh, 208Cí
whatever that means) from an industrial chemical supplier for $8/kg but
I had to buy a 25kg bag. There are people on ebay selling granules for
$10/kg but Iím not sure if it is the right type for filtering air.
first attempt at a filter is still going strong after a year, but if
the carbon starts to let smell through, people who use carbon to filter
distilled alcohol claim that it can be rejuvenated by heating it up red
hot in the microwave (this boils off the molecules it has captured
Tutorial written by een for cannanation.com/ozstoners.com