July 11, 2016

***Update*** Our kilo spools now include a vacuum resealable bag just to make preserving a little easier. 

We like to ensure all filament arrives as fresh as the day it was extruded by providing a well packaged box. However how does one keep filament fresh once opened? Since many different environments fluctuate, first we need to understand the main causes before we can take some preventative measures. We will also include some simple ways to restore filament.

Common issue #1 Brittle Filament

A common misconception is that water causes filament to become brittle. The truth is filament including PLA is actually extruded into water to hydrate during the drying process. Without this important process filament wouldn't be flexible enough to spool.

Brittle filament is often caused by the plastic becoming dehydrated due to humidity in the air. Think of filament like dried spaghetti. When you put spaghetti into a boiling pot, it begins to re-hydrate which restores its flexibility (and its tastiness).

Another major culprit of filament become brittle is our favourite star! The sun. The reason? UV light degrades the molecule bonds which holds filament together. 

In short. Humid weather and UV light are the main causes of brittle filament.

Common issue #2 Sizzling or Bubbling Filament

Sizzling is actually water boiling within the filament. It happens pretty much the moment it hits the extruding chamber due to its high heat, low volume environment. Sizzling is a little more rare, and its commonly caused by a long period of water exposure of which the filament absorbs the water like a sponge. 

Dehydrating filament will fix this issue. We recommend using an oven at 80C for 3 hours to essentially remove excess water from the filament.

Prevention methods

Method 1 Put the spool back in the box when you aren't using it. This will literally keep it away from UV and most moist environments. We have been doing this for years living in sydney which has worked flawlessly. We recommend keeping the decant crystal bag in the center core hole.

Method 2 Find a suitable Tupperware container and place it in a cupboard away from UV light and moisture.

Restoring brittle filament - Re-hydrating
  1. Cut at least 2 meters of brittle filament off the role.
  2. Boil some water in a large pot. 
  3. Place the 2 meters of brittle filament into the boiling water with tongs for 6 seconds.
  4. Allow the re-hydrated filament to dry completely (we recommend at least 24 hours). Do not dry the filament in direct sunlight.
  5. Test the re-hydrated filament with your 3D printer. If filament sizzles when printing, we recommend repeating the process 1-5 again, but only re-hydrate the filament for 2-3 seconds. If the filament is still too brittle, repeat process 1-5 again but re-hydrate for 10-12 seconds. If the 2 meters of filament prints fine, proceed to step 6.
  6. Submerge the entire spool in boiling water for the same amount of time which worked above. 
  7. Allow the spool to dry for at least 24 hours.
  8. Your filament roll is now hydrated and ready to use again.

Things to note: You should only perform the above if the filament becoming brittle is a major issue (bowdens extruder setup). Please be careful not to burn yourself on boiling water. 

Restoring sizzling filament - Dehydrating
  1. Preheat an oven to 85C
  2. Cut 2 meters of filament from the roll
  3. Put the filament into the oven for 2-3 hours.
  4. Test the filament. If bubbling still occurs, complete steps 3 again using for a longer period of time. If it prints fine, proceed to step 5.
  5. Put the entire roll into the oven for the time which worked in step 3.
  6. Your spool should now have dehydrated any excess water from the filament. 

These are methods which have worked for us in the past. Obviously when it comes to 3D printing, somethings work better than others and it comes down to your personal preference.

If you have any other methods which have worked, we'd love to hear them! Please comment below! Also if you have any suggestions or edits to this article please let us know!

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Product Information
Kilogram Spools


50 / 100 gram coils