I ordered a roll app one year ago - it is still unopened and seems to be perfectly sealed. The plan was to use it for disolvable support.
I will start testing/use it, when the new CURA with dual filament size support is up (nallath mentioned something like this @ UMForum).
Does anybody have some hints if it is enough to store it in a lock&lock container with app. 500g silica gel, take it out for printing and then back in..??
PVA is very hygroscopic so once you opened that sealed bag it will start absorbing water.
I would recommend that you plan your printing to avoid leaving the PVA in the printer longer than necessary.
And be very careful not overheating it!
It appears that wet PVA can be recovered by drying it. (Haven't tried dissolving it after drying though).
By mistake, I dried the PVA for 50 hours at 80 C, instead of the planned 20 hours, and now it certainly feels very dry again
When it absorbs water it gets soft and sticky like boiled pasta, so you will for sure notice that something is wrong with it.
Whether an air tight box with silica is enough is difficult to tell, but I would expect it to stay good very long in that environment.
The next step would be storing it under vacuum, which guess is not an option for most of us.
(We have plenty of vacuum storages and pumps at work and working with those really makes me not
want one at home