Humidity Control For Filament Storage - How Tight Does a Container Have to Be?  

Humidity Control For Filament Storage - How Tight Does a Container Have to Be?

I live in an extremely humid area. During the winter I don't have too much of an issue with filament getting to saturated, but in the summer it can be a serious pain. I want to build a cabinet for filament storage, so I can use a dehumidifier in the cabinet and keep my filament dry.

I'm also working with a similar solution for my printers. I have an MMU on my printer, so I'm designing it so I can keep the extra needed spools for the MMU in the print area. Also, I will have a vent hole in the print section so when I start to use smelly filaments like ASA, I can set up an automation script to wait until a print is done, then, maybe 5-10 minutes later, after it's cooled enough, the vent fan will go on and vent the smell.

I know I don't need an air tight seal for humidity issues, but just how tight a seal do I need? I was going to build the frame for all this out of lumber. In the past, for some similar work, I put down magnetic tape on the wood (or, in some cases, 1" square aluminum rods), and then used neodymium magnets to hold plastic against the tape. Doing this is far less, these days, than using plexiglass and, especially with my CNC, or my printers, when smoke or particles end up coating the plastic, I can remove it and replace it easily.

My concerns are using wood for the frame and the small gaps between the plastic and the frame. Is wood too porous for creating a dry box in a humid region? And if I use the magnets holding plastic against tape, that leaves stretches where the plastic is not being held against the tape. It's still pretty close (as long as I pull things and tighten them when I do the setup). How strict do I have to be in terms of seals and use of materials like wood to make an effective dry box for filament storage?