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Filament storage

Posted by nof 
Filament storage
December 10, 2014 10:28AM
Most manufacturers specify the environment parameters for their products to give a problem free operation.
The manufacturers of filament don't mention it at all. They say they dry it and seal the spools in plastic bags with or without silica-gel. I can understand the precautions because during the transport the environment could be very different from time to time.
Have anyone seen any figures on safe environment for the filament? It is quite easy to get a hygrometer to check the humidity at the storage place for the filament.

Edited 1 time(s). Last edit at 12/10/2014 10:29AM by nof.
Re: Filament storage
December 10, 2014 02:54PM
I just keep my filament spools in the house without any special precautions. I am in the UK. My house is generally at around 30% relative humidity inside. I have not noticed the effect of humidity but there are so many other variables going on.

Other parts of the world where there is high humidity, it may be a problem.

There is no detrimental effect to keeping filament bone dry, so maybe err on the side of caution and keep them in a plastic bag with silica gel.
Re: Filament storage
January 17, 2015 04:39PM
I would not go so far, as to say that there is an absolute need for "safe environment figures" regarding the use of 3D printing filament, as unproper storage does not render the filament per se "un-safe". But the manufacturer's recommendations to store filament in a dry environment are actually justified. Sealing the bags and adding silica-gel is not only for the sake of transport, but is necessary to keep the filament in a good "working order". You should actually continue to keep your filament in closed bags, together with some silica-gel, for as long as you are not using it.

The problem is that PLA, ABS, Nylon, Polycarbonate and especially PVA are hygroscopic, i.e. they are attracting water molecules from the ambient air. Some of the materials are less prone to attract water and some, like Nylon or PC are very hygroscopic, or PVA which is extremely hygroscopic. Once your filament is saturated with water, it can become more brittle, it can add in diameter (potential problems with Bowden-tube printers) and, generally speaking, it can cause your prints to fail. Saturated nylon can start making bubbles, not to talk about steam coming from the hot-end's nozzle (actually, this is only water vapor and is not nocive). Saturated PVA will actually start falling into pieces or break and render it completely useless for printing.

Just as dave3d, in the beginning, I did keep my filaments simply lying around in my house, where it is not too humid (or so I thought). But the humidity from the air was still enough to affect the filament and after a few problematic or failed prints, I decided to do something against it. After researching the Net, I did not find any storage solution which really appealed to me, so I devised one myself. I have actually written up about it on my blog here.

I use a vacuum bag, together with a special type of silica gel, with moisture saturation indicator. The vacuum takes care to evacute the ambient air, and the silica absorbs any remaining moisture from the filament. The color indicator tells me easily when to replace the silica. Simply dry the moist silica in the oven (it can be re-used indefinetely) and put it back into the vacuum bag once dry.
So far, I have been very happy with this solution as it works really well. Even if you dont want to take your vacuum cleaner out all the time, add the silica, let out as much air from the bag as possible and properly close it. For as long as it is in this closed environment, your filament will not saturate in water and won't pose problems while printing with it.
Hope that helps.

Re: Filament storage
January 18, 2015 01:42PM
so keep my filament in a bag and add rice so it can suck up and moister got it thanks
Re: Filament storage
January 18, 2015 05:23PM
I keep mine in 5 gallon buckets with screw on lids (available at most hardware stores) and a few desiccant packs. PLA is more susceptible to moisture problems than ABS.
Re: Filament storage
January 19, 2015 04:26AM
Aparkin, I understand why you would like to use rice, as it is a cheap and readily available alternative, but I actually advise against it.

Although rice presents hygroscopic tendencies, it is far not as effective as an industrially produced desiccant like silica-gel. Rice in comparison to silica-gel could be considered as a "weak/mild" desiccant.

Re: Filament storage
January 19, 2015 08:53AM
I concur with what "bluemax" says.
Rice isn't enough to keep filaments like PLA dry.
You also run the risk of introducing fine dust particles to the filament, which in turn can lead to clogging.

I use lots of silica-gel packs with my PLA, then seal it in a strong zip lock bag.
Water absorption tends to vary between manufacturers too. I find that Colorfabb's PLA stays 'fresh' for about 2 weeks before it's quality starts to degrade (unless I bag it up), compared to Formfutura's PLA which stays 'fresh' for about 3 or 4 weeks.

If you're not using a particular filament for a week or so. Store it in an air tight bag with silica-gel packs.
However, if you suspect that your filament has absorbed too much water, then dry it with the method as mentioned above. Drying may take a few weeks.
Or, oven bake at 50-60C for 30mins (for PLA).
Re: Filament storage
January 19, 2015 11:34AM
Thanks Scruffydoo, I agree.

However, if your oven allows it, do not put the temp higher than 50°C. PLA has a glass transition temperature of 60-65°C. This means that around 60°C, its changes from solid state to soft and may start becoming sticky or worse, fuse together.
So putting your oven at 60°C is putting it rather close. winking smiley Although, 30 minutes is a quite small time frame and you should be OK.

As for your other filaments, always make sure to check the glass transition temp in the manufacturer's spec sheet before "oven curing" it.
And please do use a convection oven (i.e. a fan-assisted oven which evens out the airflow) otherwise there may be too much heat in one place and your filament will become a huge mess...

Re: Filament storage
January 19, 2015 03:15PM
I haven't used PLA yet. I live at South Spain coast and there are about 65-70 % relative humidity here.

I have no care about Filament storage, I have had the same 6 ABS spools over the last year and I don't have any problem with it (I bought on differents providers: reprap3d.com and thingibox.com). I still use those ABS spools today.

When I started to see air bubbles on pieces (and small explosions when printing) , it was due excesive retraction on Slic3r software once I updated to 1.0 version. Slic3r retraction was 2mm and it is too much for a reprap without Bowden system. You can set up from 0.6-1 mm retraction and air bubbles dissapears.

...and Yes, if you look on ABS specification/properties , you can clearly see that it absorve too much humidity from air. But, As I said, had no problem with it.

Do you think you can take care of humidity with a lot of spools ?? [www.thingiverse.com] [www.thingiverse.com] (I couldn't find a photo that had 40-50 Filament spools in the same room, sorry).

Edited 3 time(s). Last edit at 01/19/2015 03:20PM by Lepes.
Re: Filament storage
January 19, 2015 04:17PM
I agree. I dont do anything special with my 6 rolls of ABS in FL humidity and I dont have any issues.
All the filament runs though a sponge cleaner and thats about it.
Re: Filament storage
January 19, 2015 04:39PM
@ Lepes: ABS is only mildly hygroscopic. If you have not printed with Nylon yet, then I understand why you did not experience any problems yet.
Actually, both ABS and PET are the least affected by ambient humidity. PLA does react a bit more to it, as it is more prone to absorb water molecules from the air.

But once you get into Nylon or even PVA, you will start caring about filament storage. Especially PVA will degrade if you do not store it accordingly, i.e. if you just have it lying around.

And I did not understand you last question: do you want to fill up your room with spools to take care of humidity??? confused smiley

@Floyd: Florida has quite a hot climate, the same goes for our Spanish friend Lepes. I live further up north, where it rains a lot and where it is quite humid.
And you are also only talking about ABS. Try out those other filament types and you might see that a certain kind of filament storage might be appropriate.

Re: Filament storage
January 19, 2015 11:10PM
I normally only print "working" things so im only using ABS.
Re: Filament storage
January 20, 2015 02:08AM
I found all flexible materials i tried, FPE, Ninjaflex, Plastink Rubber to be very hygroscopic. I have to store and handle them just like Nylon.

Re: Filament storage
January 21, 2015 02:14PM
So do any of the long term printers here do any actual oven drying of spools before printing? I've seen reports that doing so gives the best results (even if storage precautions have been taken).
Re: Filament storage
January 21, 2015 03:48PM
I print in ABS only. I store my opened filament in a cookie tin with silica packets. Each tin holds 2 rolls.

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Re: Filament storage
January 21, 2015 04:58PM
So do any of the long term printers here do any actual oven drying of spools before printing? I've seen reports that doing so gives the best results (even if storage precautions have been taken).

I have done this a few times when an older spool of filament acts up and does not want to print right. And it did fix the filament.
Re: Filament storage
January 22, 2015 08:04AM
I dry all my Nylon based and flexible filaments in the oven for a couple of hours before printing.

Re: Filament storage
January 22, 2015 02:55PM
I wonder if one of those cheap food de-hydrators could be used for this purpose?
Re: Filament storage
January 22, 2015 08:37PM
I use a convection toaster oven that I modified with a PID controller years ago for a different purpose.

A dehydrator might work since that's what it does to foods.
Re: Filament storage
January 23, 2015 05:47AM
I print ABS only and I don't need to store it in a particular way grinning smiley

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