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This episode is about the storing of filament, and what you should do if your filament get's damp

A common problem known to the 3D printing community is damp filament, which causes a wide selection of problems whilst printing. These issues revolve mostly around the quality and strength of your prints, but in more severe cases prevent you from printing entirely.

Image courtesy of CNC Kitchen

All filaments we as a community are capable of printing, are currently made from a class of material known as polymers. Polymers are grouped as they share several properties in common, one of the more negative traits happens to be the natural absorption of moisture from the air around them. Depending on the polymer in question, this absorption occurs at different rates.

Some polymers have such a high rate of absorption that these filaments will stop functioning properly within no time at all, we refer to these as ‘problem polymers’. The ones you need to be aware of are:

PVA

PVB

Nylon

PETG

PLA

For a more in-depth look into the science behind what is going on here feel free to check out this CNC Kitchen video which we helped with, gathering data about the impact humid conditions make on a wide selection of materials’ printability.

Keeping it Dry

Individuals who possess this knowledge habitually store any ‘problem polymer’ type filaments they pick up in dry conditions to keep them functioning as intended; much in the same way you would store your milk in the fridge.

 

 

 

Keeping your filament dry can be done in a multitude of ways and is mostly just a matter of applying common sense. You’ve got the options to purchase professional grade dehumidifying chambers, DIY your own solutions, or simply store the filaments in places which don’t let in a lot of moisture, such as an airing cupboard. Regardless of your decision, your filament is going to be much better off than making no effort at all.

Is my filament screwed?

 

You may have stumbled across this post because you’ve learnt the hard way about the chemical properties of a filament, or maybe you had a filament that used to print beautifully but now prints with hissing and popping, or has noticeably increased stringing and surface bubbles. These are all common signs your filament is damp. Although under most circumstances, filaments can be revived and restored to their former printing glory.

We’ll tell you how, but you must promise us that you’ll take better care of your filaments in future, deal?

Bringing Your Damp Filament Back to Life

Drying out damp filament, much like keeping filament dry is relatively easy. The most popular method involves warming the filament in dry surroundings in order to evaporate the moisture within it. However, you need to remember to not heat it past the point where the filament begins to liquify, stick to itself and turn into one enormous and (not very tasty) cookie of useless plastic.

Different polymers begin to liquify at different temperatures - known scientifically as their ‘glass transition points’. It should be noted here that a polymer’s glass transition point is much lower than the temperature your HotEnd is heated to in order to print with it. Whilst being printed, filaments typically don’t spend enough time in the HotEnd to reach the same temperature as its surroundings. Ergo, although PLA prints at 190-210C, it actually reaches its glass transition around 65C.

What we recommend is that you find a method of heating your filament to around 50-60C and leaving it there for around 6-12 hours. Frustratingly, drying filaments out is a slow process and will take hours; so if for some reason your oven isn’t available for 12 hours straight, your printer’s heated bed is commonly overlooked as an alternative- (regretfully this will almost certainly prevent you from printing during this period of time ☹). If your printer doesn’t have an enclosure it’s advisable to create a mock up one to ensure even drying; this should be out of a non-flammable box or bag (blankets are also effective) that can safely cover both the bed and the filament.

 

 

If you do however have a budget, drying filaments can be less of an ordeal. There are options to use specific appliances- more commonly used in laboratories and factories than the household, which are specifically designed to evacuate the moisture from things. These are often rather pricey for what they are though, and the same effect can be achieved by using a kitchen food dehydrator for a fraction of the cost.

 

These appliances are more reliable than simply using an oven and are designed to be left on and circulating heat for long periods of time. They are also more efficient as they often have less space to fill when heating up. But, even with a dehydrator, you’ll still be waiting hours, so ideally the way of minimising your ordeal entirely is to just keep your filament dry in the first place. Before purchasing any new ‘problem polymers’, mentally consider where you’ll store them whilst in and out of use.

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