3DPrinting

I've used these in a drybox to keep filament dry, and they work really well for that, but to actually dry filament I use what amounts to a modified food dehydrator. You really need heat and airflow to get moisture out of already wet filament. If you don't have a food dehydrator you can use, you can also try an oven, but be careful of temperature fluctuations which could cause it to get too hot and melt your filament.

I use them in my safe, they work well for that but would probably do fine for filament. I like that you can just plug them in to dry them out, pretty convenient!

FYI AFAIK desiccants don’t actually dry out the filament, they just prevent it from getting any wetter. To truly dry it, you could get a filament dehydrator or use a modified food dehydrator (among other options).

With that said, you might be able to use those, personally I’d just recommend collecting those “do not eat” packets that come with things and throwing those into your drybox.

They’re usually just little cloth packages of desiccant beads.

Personally, I store my filament in ziplock bags with a couple of those packets and it seems to work well for the most part. I also have a dehydrator (modified food dehydrator) though, which I use on filaments that were left out.

On a related question, is "desiccant refresher" a thing, as in a reasonably small device that will heat a small quantity of those beads to something like 120ºC while keeping a slow air flow?

Yup, it’s fantastic.

Just a bucket full of silica gel will do👍

They work really great for keeping dry filament dry, and seem to help drying out wet filament to a degree. I use a food dehydrator to dry wet filament, then store my dry filament in a plastic tub with one of these. They recharge decently quick, and I don't need to recharge them very often. I put one in a bin with 4 spools of filament and recharge every few months or so.

I have one. Works fine. I've had to plug it in once so far.

Haven't bothered with one of those since getting just the beads is probably way cheaper.
I store my filament in an Ikea Samla box with added weather strips to decently seal it and just added 1kg of beads (orange to green color change) with a spacer grid to the bottom of the box. Constantly keeps the RH in the box around 20%, and I only have to dry the beads 1-2x per year (in the oven).

Personally I use a food dehydrator for drying my filament and use dehydrating beads for storage

The ones I got have instructions for baking to get them to be dehydrated again

Just be sure that if you go that route you don't get the indicating ones as they can be pretty gnarly health wise

I use a hygrometer in the storage container to check the humidity. Once it gets above 20% @ 75F I dehydrate them again