A new V2 DIY filament dryer build revisits an earlier controller-enhanced design, upgrading it with a custom PCB and an open GitHub project. The core setup uses an SHT30 humidity/temperature sensor and a 100K NTC temperature sensor to control a 12V polyimide r
The moment you print with damp filament, you feel it in the results—brittle strands, stringing, and a frustrating session that starts with a simple material problem. For people who have lived through that, a filament dryer isn’t a luxury. It’s the line between a clean print and a waste bin.
In a recent video, [Saša Karanović] revisits the DIY filament dryer he first tried a couple of years ago. Back then, he reused an existing filament dryer, then added a custom controller to improve performance. That version—technically not fully DIY—earned some feedback. The V2 build is his answer: a more deliberate DIY approach. backed by a custom PCB and a GitHub project where the full details are laid out.
For readers who want to jump straight into the work, the available documentation covers assembly steps and the BOM. The build starts with a container-style setup—described at its core as a container such as a shown 5L food storage type. Inside, a humidity and temperature sensor from the SHT30 family and a 100K NTC temperature sensor do the sensing work. Those sensors feed into the controller board.
The controller board then switches the 12V polyimide resistive heater on and off. In other words, the dryer’s operation is built around a loop: measure conditions, heat as needed, stop when the system calls it done.
But there’s a snag that comes up again and again in filament dryers, DIY or otherwise. In this design, saturated warm air has nowhere to go. That matters because the dryer isn’t just about adding heat—it’s about moving moist air out and bringing drier air in so the filament can actually give up its moisture.
The build’s own explanation points to the common workaround: even commercial filament dryers. including the common Sunlu types. are recommended to be left slightly ajar. The small gap lets moist air be replaced with cooler air that can absorb moisture more readily. It’s a practical reminder that in filament drying, airflow can be just as important as the heater.
Now. with the V2—custom PCB. documented assembly. and a dedicated GitHub project—the DIY side of filament drying looks more structured than the earlier controller add-on. The remaining challenge is also familiar: without a way for that saturated warm air to escape. the system can only do so much. For anyone building one, the next improvement may not be another sensor. It may be the venting plan.
DIY 3D printing filament dryer moisture SHT30 100K NTC polyimide heater custom PCB GitHub airflow
So basically you just need… a heater and a humidity sensor? Seems overcomplicated, my buddy just leaves filament in a box forever.
I don’t get why people need dryers at all like it’s not food. If it’s damp just print slower? Or is that not how plastic works??
The part about “leave it slightly ajar” is the key right? But also if you open it then doesn’t humidity get in from the room…? My brain hurts. I built one of these and it just made everything smell like warm electronics lol.
They’re using a 12V polyimide resistive heater, which sounds like it’s gonna work great until you remember polyimide is like… not even the same thing as filament? Also the SHT30 sensor, is that the one that reads temperature wrong? I swear my cheap sensors always drift and then you end up baking it and it turns brittle anyway.