How necessary is airtight (or nearly airtight) storage for PLA? I was going to make a storage system based off of http://www.thingiverse.com/thing:814597 but I was wondering if it’s worth it. The tubing alone will cost around $45
Honesty, I’ve never had a problem. I’m still using a roll of PLA that has been out for over a year now.
Though I did notice a few months back that prints started becoming stringy, but dropping the hotend temp by 10 degrees seemed to fix it.
I wouldn’t expect a perfectly airtight system would show an appreciable advantage. I think you’d be ok if it was reasonably sealed as in the example or with some weather stripping in plastic tote. I would concentrate more on an easily maintainable desicant system. I use a mason jar with damp roof in it. It works, but it’s on my list of improvements.
I should have said this when I posted. If sharing personal experiance please tell me the filament brand.
@Tom_Nardi what temp did you drop it from/to?
I used to print at 200, now I’m at 190.
I’ve been using PLA from Zen Toolworks, been very happy with it.
I think the correct answer is: It depends.
If what I’ve read is correct, that PLA absorbs water from the air and becomes difficult, if not impossible, to print with, then you first need to determine:
a) how humid is your environment and
b) how long are started spools of filament going to sit around before being consumed.
Assuming you have a humidity problem, then yes - the more air tight the storage the better. $45 doesn’t replace very many spools of damaged PLA…
@Josh_Kieler I was planning to buy http://www.amazon.com/gp/product/B00DYKTS9C?psc=1&redirect=true&ref_=ox_sc_act_title_4&smid=A17QCEXR2SHYMI to line the bottom of the bin.
@Alex_Wiebe I live in north NJ so it comes and goes in extrmes. I just looked up average humidity for NJ and it’s 71%
@Adam_Steinmark Using those silica packs, yes you will need airtight and you will likely need to replace them whenever open the container. I would use a tub of this http://www.amazon.com/DampRid-FG50T-Hi-Capacity-Moisture-Absorber/dp/B0029EGUNG/ref=sr_1_2?s=home-garden&ie=UTF8&qid=1436812952&sr=1-2
Far more robust, and you know when it’s spent. Desiccant packs are great for vacuum sealed stuff but not so much for persistently humid environments.
Ideally you would suspend the salt above a collection vessel, for the water to run into. Damprid actually sells a container that does this, but it may not fit in your chamber.
It’s not a huge issue for PLA. You want it to arrive vacuum-sealed with silica, because who knows what environments it’s been subjected to otherwise. Some other materials, notably nylon, polycarbonate, and especially PVA, need protection from moisture much more.
@Josh_Kieler Do you think it would be fine to use the system I’m planning (nearly airtight) and coat the bottom with the DampRid? Then just replace the crystals as needed? The filament would be on a spool holder so it wouldnt be touching the base of the container.
No damp rid turns into gel (goop) as it absorbs water… It needs to be inside a container… But you can buy it at the store that way, which comes with a collander of sorts to suspend over the goop collecting in bottom. big bucket is for refills
@Josh_Kieler @Thomas_O_Connell So DampRid needs somewhere to drain. I can’t really get a big enough container for drainage room. And it will be difficult to create an effective system to drain without compromising the integrity of the entire system.
Won’t the silica packets work fine? I know it’s not airtight but the silica should be able to absorb most of the humidity and I could open a pack and put it in a small dish in the middle to see when the packs need to be replaced.
@Adam_Steinmark
Silica gel is used to maintain humidity (which is why it’s often used in sealed museum cases)… We generally buy it very dry, so that it absorbs moisture from the air. Once it reaches equilibrium, however, it will release moisture, maintaining a steady relative humidity.
Damp-Rid (Calcium chloride) will remove much more water from the air, but requires a way to keep that water from re-evaporating. (I use the hanging version with a Mylar reservoir at the bottom.)
@Adam_Steinmark Silica doesn’t have near the capacity that Damprid/Calcium chloride has. You could empirically determine how many silica packs you will need for your size container, but they will not likely keep up, if poorly sealed.
Another possibility, if you can’t provide somewhere to drain is Drierite/Calcium Sulphate. https://secure.drierite.com/catalog3/default_home.cfm
A typical laboratory desiccant chamber uses this, and it remains in salt form. It is more expensive and if you do not use the name product you will need a way to determine when its spent. The product proper turns from blue to purple.
I highly encourage you to use Damp-rid in this setting. However, if that does not suit your needs. Flushing out an alternate method can be rewarding as well.
If you do go a different route, I would be interested in the results. I find it interesting to see how different people solve different problems.
Just for the record… I have a huge box plastic container, with a damp rid thing in it. Yes, everytime I open the lid I let humid air in but I don’t sweat it. I leave whatever pla i am using out for week at a time. ABS i make an effort to put back if its going to be overnight before i need it again. So far so good… One thing that I hasnt fixed is taulman bridge nylon… That stuff came wet and even after 3 weeks its still hissing when printing. I may try pulling off 10m or so away from the spool and see if that dries out OK vs needing to bake it.
I might just do what I was going to do and bake the silica every time I open it. Or maybe just the container and silica.
K, think you may be over concerned about it IMHO but its a hobby so to each his own 
good luck
@Thomas_O_Connell So you think I don’t need any storage system?