Reddit reviews Best Value Vacs 3 Gallon Aluminum Vacuum Degassing Chamber- Purge, Degas, Silicone, Resin, Epoxy

Just a vacuum. My chamber is aluminum and is a bit more expensive setup than a food dehydrator, but I bet a small chamber could be printed, which would bring the cost down. Another substantial cost is the pump itself. It MIGHT be possible to do this with a hand operated vacuum pump if most of the void space could be elliminated within the chamber, maybe with rice or a desiccant. Basically you want most of the air out when you start so you don't have to pump much.

In summary, with a printed vacuum chamber (would need to be well engineered to prevent implosion which would not be fun) and a hand pump this could actually be quite a bit cheaper than alternative methods. It's definitely safer for your spool and oven, lol!

Oh, and an interesting thing about the desiccant: It gets quite warm when it's adsorbing moisture, but not nearly warm enough to melt any 3d printer filament that I'm aware of. This warmth should make the filament dry out even faster. It also will keep the pressure in the chamber lower since it will adsorb water vapor surprisingly quickly.

Now if I can get an analytical balance we'll be in business!