So much for sealing the basement safe door:
The desiccant definitely lasts longer during the winter, even though the dehumidifier fights the basement air to a standstill around 55%RH during the summer.
Each desiccant bag contains 500 g of silica gel and the most recent one adsorbed 73 g of water.
The Smell of Molten Projects in the Morning 
I’ve wanted to get a fire-resistant strongbox for important papers for a while now, and recently almost settled on one. I went to the Sentry web site to look up more details to understand the differences between models, and came across a small note on one that it wouldn’t be suitable for stamps or moisture-sensitive jewelry. It turns out that one way the manufacturers protect against the heat of a fire is to line these things with, essentially, wet insulation. If I recall correctly, the moisture in the insulation boils off to absorb the heat and keep it away from the contents of the safe for as long as possible.
Are you sure you’re fighting moisture from the outside and not from the safe’s insulation itself? I want to store some old photos and a family document from the late 1700s, so I’m looking to keep the contents as dry as possible as well.
The interior is a molded plastic shell with only four bolt holes, putting the insulation outside where it can’t do much damage until an inferno melts the shell. That insulation has long since equilibrated with the 50% RH basement air, so I’m pretty sure it’s all leakage around the door gasket and up past the anchor bolts.
The “media safe” in the garage came with a bunch of warnings to open the door at least once a month to let the insulation breathe, which I’ve been not doing for decades. If all those Windows CDs turned to mush, it wouldn’t be much of a loss; they may have already gone bad, for all I know.
If you’ve scanned them, those bits should outlast everything else, assuming the programs required to process them also survive. I’d put my money on the paper, though, as it’s got an excellent track record. [sigh]
Make sure the safe can’t get flooded: in this day and age, water may be more likely than fire!