The PolyDry Filament Storage System

By on January 20th, 2020 in Hardware

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 The PolyDry storage system for 3D printer filament spools [Source:] The PolyDry storage system for 3D printer filament spools [Source:]


I’m looking at a new offering from Filaments. ca, the PolyDry storage system.

This unit is not a 3D printer itself, but really should be a part of any serious 3D printer operation. It is a standalone unit providing a controlled environment for filament storage that helps ensure the quality of the materials over long periods of time.

It’s not surprising that this device has been developed by, who are a leading Canadian-based supplier of 3D printer materials. They know a great deal about 3D printing materials, and have recognized an ongoing problem in the industry that needs solving.

That problem is humidity.

It turns out that many 3D printer filament materials are hygroscopic; that is, they readily absorb water from the air. Some material types absorb water more rapidly than others, and some are particularly voracious when it comes to humidity.

When water is absorbed by a filament there is often no visible change. Instead, you notice the problem when you use the filament in a 3D printer. As the water-logged filament enters the hot end, the temperature rises and the water essentially boils in tiny amounts.

This cause the formation of bubbles in the thermoplastic flow. Sometimes the corruption is so bad you can actually see and hear the bubbles as they exit the hot nozzle. If you continue to 3D print with this material, you will obtain weak 3D prints with poor surface quality. If you’re 3D printing and that happens, it’s best to stop the print and get some new material.

Filament is inevitably shipped from the manufacturer in a sealed bag for this reason. The bag will also include a sachet of desiccant to absorb any stray humidity before it is absorbed by the filament.

However, once opened, the filament is now exposed to the ambient atmosphere, which is typically much higher humidity than recommended for filament storage. While a fresh spool is likely good for a while, after days or weeks, depending on the type of material, the thermoplastic will be infested with water molecules and thus not usable.

Some materials are extraordinarily affected by humidity. Nylon and PVA, for example, are ruined if exposed to humid air for only a few days.

The solution is to keep filaments dry.

How is this done? There are two approaches being done these days. One is to incorporate a filament-drying chamber into the 3D printer itself. Usually these are conveniently located and can be used to store spools while they are deploying filament for 3D printing.

However, there is a problem with that approach: capacity. Usually such systems only allow for the storage and use of one or two spools at a time. What do you do if you have more than one spool on hand?

You will have more than one spool on hand, because almost everyone has multiple types and colors of materials handy. These are usually in a collection of partly-used spools. Most of the time these are hopefully stored in sealed bags with desiccant, but sometimes not.

Some 3D printer operators have attempted to create “dry boxes” by using a sealed container and tossing in a lot of desiccant. Others have modified food dryers to dry a spool or two, but these are neither reliable nor of large capacity.

Enter’s PolyDry solution.

It’s a cabinet-style device that holds a rather large amount of filament and is guaranteed to keep it dry.

The PolyDry unit includes monitoring circuits to ensure its contents are kept at a consistent humidity level that you set. The digital control panel can set the humidity to as high as 50%, but as low as a bone-dry 3%.

The door to the PolyDry chamber is magnetically sealed and includes an alarm should it be inadvertently left open. There are also alarms if the unit is unable to maintain the set humidity level for any reason.

What’s really attractive about the PolyDry is that it is totally sealed to air and dust. This means there is no need whatsoever for bags or desiccant. Just toss the spools on the PolyDry’s shelves and you’re good to go.

 The PolyDry storage system has three shelves for 3D printer filament spools [Source:] The PolyDry storage system has three shelves for 3D printer filament spools [Source:]

And about those shelves: the PolyDry is enormous. It’s reconfigurable shelves are within a massive 680l air-tight chamber that is able to handle spools of up to 10kg of weight each. says the PolyDry can accommodate up to 150 standard 1kg spools! That’s an enormous number of spools that should be suitable for almost any organization.

Let’s put it this way: if you store the factory-sealed filament spools outside the PolyDry unit, how many partial spools do you have on hand? Likely something less than 150, so the PolyDry is probably a solution for almost everyone.

 Each shelf of the PolyDry storage system can accommodate many 3D printer filament spools [Source:] Each shelf of the PolyDry storage system can accommodate many 3D printer filament spools [Source:]

With the introduction of high temperature 3D printers, this issue has come forward more strongly, as many of the high temperature materials are particularly sensitive to humidity, such as PEEK.

Many early high temperature 3D printers configurations somehow did not realize this and thus they were unable to properly 3D print PEEK. It’s only recently that we’re starting to see integrated environmentally-controlled filament chambers. If you happen to have a high temperature 3D printer without on-board spool storage, you will need an external unit like the PolyDry.

Even if a 3D printer includes an on-board environmentally-controlled spool chamber, your best bet is to always store the filament spools in controlled environments after being taken out of the 3D printer. This means you could need a specialized storage unit like the PolyDry in addition to the storage of the 3D printer itself.

One very interesting feature of the PolyDry is that it is a maintenance-free unit. The drying unit is “self rejuvenating” and does not require any attention.

Finally, the PolyDry storage system is set on casters so it can be readily moved about in a workshop, and can also be locked to prevent unauthorized access to expensive materials.

The PolyDry 3D680 is available for purchase for only CA$3,495 (US$2,670). For 150 1kg spools, that’s only US$18 each for maintaining high filament quality.


By Kerry Stevenson

Kerry Stevenson, aka "General Fabb" has written over 8,000 stories on 3D printing at Fabbaloo since he launched the venture in 2007, with an intention to promote and grow the incredible technology of 3D printing across the world. So far, it seems to be working!