Print 2 plates of the stl.

Cut up some sort of filter medium. (I used a very very cheap no name furnace filter)

Hot glue the filter into the bottom plate

Hot glue the filter into the top plate.

If you want to be really cool-pro you could use some form of silicon gasket material in place of the hot glue.

To amuse said friend this is the Warranty I offered
(shamefully edited and stolen from Saturday Night Live)

Warning: Pregnant women, the elderly, and children under 10 should avoid prolonged exposure to the AF-100-4x3x4.
Caution: the AF-100-4x3x4 may suddenly accelerate to dangerous speeds.
the AF-100-4x3x4 contains a liquid core, which, if exposed due to rupture, should not be touched, inhaled, or looked at.
Do not use the AF-100-4x3x4 on concrete.
Discontinue use of the AF-100-4x3x4 if any of the following occurs:
itching
vertigo
dizziness
tingling in extremities
loss of balance or coordination
slurred speech
temporary blindness
profuse sweating
heart palpitations
If the AF-100-4x3x4 begins to smoke, get away immediately. Seek shelter and cover head.
the AF-100-4x3x4 may stick to certain types of skin.
When not in use, the AF-100-4x3x4 should be returned to its special container and kept under refrigeration. Failure to do so relieves the makers of the AF-100-4x3x4, and its parent company, T.P.G., of any and all liability.
Ingredients of the AF-100-4x3x4 include an unknown glowing substance which fell to Earth, presumably from outer space.
the AF-100-4x3x4 has been shipped to our troops in Saudi Arabia and is also being dropped by our warplanes on Iraq.
Do not taunt the AF-100-4x3x4.
the AF-100-4x3x4 comes with a lifetime guarantee.