Deodourizer Pucks

After accidentally spilling the baking soda one too many times, I came up with this deodourizer puck system which uses a solidified block of baking soda mixed with activated carbon to produce a non-spillable deodorizer puck which can be used a bit more flexibly than a capsule of baking soda.

The printed parts consist of the reusable outer ring which contains the deodourizer blend, and the hopper and tamper used to compact the soda/carbon mix into the puck. One outer ring is required for each puck you wish to use at once, but a single hopper and tamper can be reused effectively indefinitely. The outer rings can be re-used when the pucks eventually run out by knocking the puck out into the bin (or composter, the mix ends up fairly nice for your home compost)

Why it works

Baking soda (Sodium bicarbonate) reacts with acidic compounds in bad-smelling gases and vapours, neutralising them to get rid of the smell. This reaction depends on the baking soda having free surface area available, which is why you normally keep it powdered for maximum reaction space.  Powdered baking soda is annoying to deal with though, which is why I've made it into pucks. Unfortunately, making it a solid puck also means limiting the surface area for reaction to the exposed outer surfaces.

That's where our good friend activated carbon comes in. The carbon acts as an adsorbent to physically trap odours, and also helps create microscopic pores within the soda puck to increase the available surface area of the soda. The combination of the two in my (so far very unscientific) testing works better than one alone to clear up bad smells. 

Creating the Pucks

Print settings

These designs work best with a 0.4mm or smaller nozzle. Otherwise, there's not much need for fancy print settings, other than possibly turning on thin walls so your slicer doesn't ignore the retaining lip in the hopper. All parts can be printed without support.

Materials

• 1x Tamper.stl

• 1x Hopper.stl

• 1x Outer_Ring.stl

• Activated charcoal powder (I got mine by some ripping open some supplement capsules, but it's easy enough to buy as a powder)

• Sodium bicarbonate (baking soda)

• A little bit of water

Instructions

1. Print all of the parts.

2. Slot the inner lip of the hopper into the outer ring.

3. In a bowl, mix 1 part activated charcoal powder to 3 parts baking soda. Add water a few drops at a time until the mix resembles damp sand

4. Fill the hopper and outer ring loosely with the powder mix - it doesn't need to be compacted down until you're pressing it

5. Use the tamper to press the powder into the outer ring. It should end up a little below the edge of the outer ring.

6. Remove the tamper and hopper, and let the puck dry out for 48 hours before use