Desiccants and Storage

[HO RacePro]

I've made my own desiccant sachets -- much larger than those typically supplied with reels of filament. I've purchased desiccant by the quart/pound and loaded it into cotton drawstring bags. The desiccant I bought on eBay. The bags came from McMaster-Carr (www.mcmaster.com). Each bag holds about 130 grams of desiccant.





I store all of my filament in snap-top plastic bins made by Rubbermaid, their part number 1776473. I store each reel of filament along with two sachets of desiccant.



I own a PrintDry brand filament drier -- the original model which was converted from a food drier. I have designed and printed two desiccant racks that fit inside the drier along with a reel of filament. While printing I set the drier at 140 to 145 degrees Celsius and load two bags of desiccant inside. This is maybe not the ideal way to make sure the filament is dry, or to dry out the desiccant, but it seems to work well enough. I have not been having any issues with wet filament.



FYI, the desiccant racks were printed in PLA and are two-part assemblies with glued pin-and-socket joints. On one of them the joints failed, but I was able to fix it. If I was to make new ones I'd use PETG, which is my current go-to filament for anything that needs to be rigid. For flexible parts I use TPU.

[Kevan]

From what I can gather silica gel is only good to keep the air dry, it won't draw moisture that's absorbed into the filament, to do that you need heat to get it into vapour...i.e. food dehydrator.

[HO RacePro]

If you dry the air enough moisture will desorb from filament. Definitely not as quickly as it will at higher temperatures, and maybe not as thoroughly.

But the whole point is to keep the filament dry in the first place. If it comes sealed vacuum-packed in a heavy gauge bag along with some desiccant you can expect it to be dry. If you want to be certain you can dry a fresh reel before use and then store it in an air-tight container with a couple bags of dry desiccant.

[Kevan]

Vacuum packed is all good but air pressure is the wrong way round if you want to keep moisture out.

[4424ever]

I store mine in large zip lock bags with desiccant

[HO RacePro]

Zip-Lock bags are still permeable to moisture. Which is why they sell freezer storage bags -- heavier gauge to reduce their permeability and forestall freezer burn. Probably worth the extra bux.

[MrFlippant]

Dessicant absolutely can dehydrate material. It just takes longer than a dehydrator.
If you don't believe my personal experience, hopefully Stefan can convince you.

Also, it's worth noting that the "health reasons" he refers to with respect to color change dessicant is about the blue stuff, which uses cobalt. But, as long as there is no direct contact with your skin or the filament, you should be fine. Besides, most people consider 3d prints of any kind to not be food safe because they can't be properly cleaned due to layer lines.