Proper care of filament.

I've been hearing that filament can be ruined by too much humidity.

What is the proper way to store it?
What does bad filament act like when extruded? Can you tell by the way it looks or acts?



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Ruined is a harsh term I think. Filament like almost anything else in the world can absorb moisture. Sure you could keep all your spools in an air tight container Macgyver up some contraption to allow it to only be exposed to air as it is extruded but that would all be a bit over kill. With ABS and PLA your biggest thing will be the diameter of the filament, it will swell as it absorbs excess moisture. It is good practice to always measure your filament in 3 different spots and average them together before any print to get the most accurate measurement so that the software can extrude the correct amount of filament. If we are talking nylon which extrudes at a much higher temp you will hear popping and see steam come off the extruder as the water boils out of the filament.

This will result in a poorer print quality in general. Nylon pretty much should always be dried before use (measure out how much you need, pop it into an oven at around 90 degrees C for as long as you can (a few hours is good) and then print. For ABS and PLA try to keep the spools in a bag with some desiccant if you are in a humid area. If you have a room dedicated to your printer and filament storage using a de-humidifier would help too.

 

Moisture with PLA is definitely an issue. At least, it has been for me. I print only with PLA currently. I had some PLA that was printing fine at first but I'd left it out for about a month, and... I live in Holland. It rains ALL THE TIME here, and when it's not raining, it's misting. I started printing again and the damn thing just did not want to print well - globbing, stringing, not smooth at all, even though it was the same settings I had used before.

So I stuck it in the oven on a low setting (about 50c, well under the temp that any filament globbed on the end of the extruder starts to soften, as I'm not sure how accurate my oven is) for a few hours, and it was -much- improved. Not like how it was when it was "fresh" but a lot better... Usable for parts that don't have to be perfect. I'm not sure how much moisture it removed as it weighed the same before and after, but my scale only goes to the nearest gram.

I'm going to be building an airtight container for my unsealed filament with dessicant, and keeping any new filament in the bags (it does come with dessicant and the bags are vacuum sealed, at least from Plastic2Print, which is based in Amsterdam) until I'm ready to use them. Also planning on building a second, smaller airtight box for the actual filament I'm using at the time, with a spool holder in it, moar dessicant, and a hole in the side of the box just big enough to feed the filament and well sealed with a little rubber/foam tube, so if I just let it sit for a while without being used, the filament in the box won't be exposed to moisture in the air. Overkill, maybe, but I want to eliminate as many variables as I can which might interfere with getting a perfect print every time.

 

I have been confronted to the same problem of humid filament. I have tried out a few ways to keep it dry, but the one I found the easiest was to use vacuum bags. If I have spools I don't need immediately, I put 4 together in a vacuum bag, add some silica gel with moisture indicator, vacuum all the air out (that makes a nice compact package) and store the bag(s) in a carton box. They are also easily stackable, if necessary.

The advantage is that the transparent bag will allow you to see the state of the silica gel (yellow = dry, gree = needs replacement), but you can also easily read the labels, if you are looking for a specific spool. If you use a box, you need to put labels on the outside.

I have written up a short article about this project. If you are interested, I invite you to read up about it here: http://3dprintingforbeginners.com/how-to-store-3d-printing-filament/
I would love to hear what you guys think about this solution.