I haven't had good storage for any of my filament for over a year. Fortunately, it doesn't seem to have taken on much water, but I decided it was time to make a proper storage container.
This whole project cost me $8 for one container, including enough DampRid to last years. One 2.5 pound bag of DampRid is enough for at least a dozen containers.
Step 1: Materials
All you need is:
- A 5-gallon bucket
- Bucket lid with seal
- A refill bag of unscented DampRid (or a desiccant of your choice)
- A plastic container strong enough to support your filament reels
- A hygrometer (optional)
You could get a container of DampRid that comes in its own little bucket, but these are much more expensive.
For the container, I used one half of a plastic clamshell package from an electronics kit.
For the bucket, I used a 5 gallon "Homer Bucket" from my local Home Depot. You could also use pretty much any other clean bucket and a lid with a seal. If you find the orange color to be unsightly, another color of bucket would work just as well.
Step 2: Assembly
Pour a thin layer of DampRid into the container and place it at the bottom of the bucket. Stack your filament reels on top of the container, put the lid on (you may have to press hard on the edges), and you're done!
Step 3: Notes and Possible Additions
As for drying performance, the air in my bucket was down to 12% humidity (from 50-60% ambient) after a few hours. After a few days, the humidity was down to 7%. After about two weeks, the humidity was 4%.
This bucket will not dry out filament that's absorbed water, but it works great for keeping filament dry.
Initially, I planned to add a small heater and fan controlled by a microcontroller to allow drying wet filament. However, this didn't work out, and I realized my filament wasn't very wet anyways. If you want to add a heater, I would suggest using a small computer fan (I tried a 92mm one) and enough power resistors to dissipate about 30-40 watts. I would recommend using resistors that are rated for at least 50% more than the power they'll be dissipating. You might need to insulate the bucket, too.
I've considered adding something that would allow the filament to remain in the container during printing. This could be achieved with a grommet and a PTFE tube leading to your printer's extruder. You'll probably need to find a way to allow the reels to spin freely, because a reel at the bottom of a full container would have a lot of trouble spinning.
It might be worth using a different means of holding the filament above the desiccant. You could try using an empty filament reel with the desiccant poured around it.