Humidity and moisture is an ongoing battle here in the tropics. Not only is it an issue when storing 3D printer filament, but everything has a tendency to rust or go mouldy very quickly. For a while I had been keeping those ‘do not eat’ packets that you find in some dried foods, and throwing them in my toolboxes or in with the printer filament.

But I wanted something better, something with more moisture absorbing power. I found these neato metal silica gel canisters. Designed for Pelican cases, you throw them in the oven for a couple of hours to cook off the moisture and ‘reactivate’ them. These looked the business, but were dear as poison. Hrmm, I have a stack of Altoids tins here that I have been collecting to bodge into something…

Photo of DIY molecular sieve altoids dessicant canister

Introducing the ‘Molecular Sieve Altoids canister’… Whoah. I know those words individually, but I have never seen them altogether like that before.

Molecular sieve is a desiccant, and like silica gel it absorbs moisture. The difference is that molecular sieve absorbs moisture faster and reduces water vapour to lower levels than silica gel. Apparently molecular sieve can even be used to dry silica gel and is often found in industrial applications like ‘drying cracked gas’. I have no idea what is entailed in drying cracked gas, but it sounds like molecular sieve is suitably overpowered for keeping my printer filament dry and tools rust free.

Supplies and Equipment

Photo of supplies and steps to build a DIY Altoids desiccant canister.

Build Instructions

  1. Use Dremel to cut a window into the Altoids lid. I used the white logo area as a template.
  2. Switch to a grinding attachment and tidy up the edges and remove any burrs.
  3. Cut a piece for flywire to fit inside the Altoids lid.
  4. Run a small bead of hot glue around the inside of the window and push the flywire down.
  5. Fill with molecular sieve 4a and start drying cracked gas. I mean, throw it in your toolbox.


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