Vacuum bags render silica gel beads ineffective?
Hi.
In order to reduce moisture content from filament spool storage, you can put them in a vacuum bag and pump out the air. Alternatively, you can add silica gel beads to the bag to absorb the moisture.
My question is, would pulling a vacuum to a bag render silica gel beads ineffective? If there's minimal air in the bag, will the moisture still travel from the spool to the silica gel beads? Additionally, when pulling a vacuum you might pull the external plastic bag so tight that it would block off an air pathway between the filament and the silica gel beads, e.g. if you keep your silica gel beads in the opening in the middle of the spool (essentially creating two different air-tight compartments).
Cheers.
RE: Vacuum bags render silica gel beads ineffective?
Wow.
Are you a rocket scientist or not.
Suggest you try both methods and let us know.
I live in a Spanish mountainous area, very low winter and summer high temps, with extreme changes in humidity, but with the use of a vacuum sealing bags
I have managed to get away with it, plus silica gel tucked into the bag.
I use humidity stickers ex Geeetech I think to tell me the situation inside the the bags holding the filament.
Strongly advise you purchase filament only for an intended project, I buy 250 gram if my 3D printing requires it.
Prusa slicer will tell you the required filament needed when you load the project onto the table.
I only buy 1 Kg spools for multiple prints, PLEASE remember in life LESS IS MORE.
RE: Vacuum bags render silica gel beads ineffective?
Haha, I actually do work at a technical university but not with rocket science.
Perhaps I'll get around to trying it sometime. If I do, I'll post my findings in this thread.
(As a side note, I actually do the opposite of you when it comes to filament. I buy several hundred euros worth of filament at a time to minimize delivery time/cost/environmental impact. I'm often printing something and filament stays good for many years if stored correctly, so what's best for my use is to bulk up!)
RE:
Regarding the original question...
Silica gel does not remove moisture from filament it removes it from the air, once enough moisture has been removed so the partial pressure in the air is less than the vapour pressure in the filament then moisture will go into the air and from there into the silica gel if it has sufficient capacity left. Bearing in mind silica gel does not have a huge capacity the first thing you need to consider is how humid the air is, if it is very humid you are going to need a lot of silica gel, but removing a lot of air it will help. In reality those little packets you get in new reels are not going to do much, you would be better off buying some reusable silica in bulk then put it in a pot in the middle of the reel.
Regarding creating separate air cells, your chances of doing this are quite small. Most reels have cardboard cores which are going to be porous and even without this having a perfect seal is unlikely, you can probably reduce movement which could reduce the diffusion of the water vapour towards the silica.
So what does this mean in practice? Reducing the air in the bag is definitely worth it unless the air starts out extremely dry. Dry silica will help but only if there is enough of it and it is dry enough, reusing little packets is probably a waste of time.
Hope this helps