I’m looking for some advice on my filament drying setup. I’ve been trying to optimize my printing quality, and I recently bought a dehumidifier, hoping it would lower the moisture in my room. Unfortunately, it hasn’t been effective enough, with humidity levels staying above 40%, sometimes even higher than outside.
After some research, I learned that reducing humidity alone might not be sufficient; I also need to introduce some heat. So, I decided to try something new - I placed the dehumidifier inside a large cooler and filled it with filament.
This method successfully reduced the humidity inside the cooler to under 15%, but the temperature gradually rose and reached 57°C (135°F) before I started venting the heat by opening the cooler’s middle section.
Now, I’m running this setup all day, maintaining humidity around 22% and a cooler temperature of 50°C (122°F). My plan is to switch it off at night and only run the dehumidifier during the day when I’m swapping out spools.
As for storing the spools long-term, I’m considering sturdy ziplock bags and rechargeable desiccant pouches to keep using my dowel rod storage shelf.
I’m working with PLA and PETG, no ABS.
Any advice or suggestions would be greatly appreciated!
I’m uncertain if you’ll receive an official response from either the dehumidifier manufacturer or Igloo. Let’s consider this logically. Igloo manufactures coolers designed to keep items cool. Some have effectively used them for winter camping by placing thermal heat bags inside to achieve the opposite effect without issue. Considering their durability, it’s plausible they can withstand car interior temperatures, which can reach 200°F (93°C). Personally, I’ve never encountered temperatures above 180°F in my car, and my many, many coolers over the years remained intact. Igloos have also resisted warping when near campfires, suggesting a high melting point. People have even placed boiling pots on them without melting, though it may leave marks.
Continuing this line of thought, we can assume the dehumidifier has thermal protection if it bears UL/CSA/TUV safety markings. If it complies with safety regulations, the concern shifts to whether it might catch fire if overheated. However, it’s more probable it would blow an internal fuse or go into thermal shutdown, as designed.
If you still have concerns, what you might employ is a dual probe thermometer or wall thermostat with a temp probe just for peace of mind.
I’ve employed this thermometer as an internal probe for gaming computer system builds. If you’re skilled, you can wire some 10K NTC thermistors and affix them to suspected hotspots using heat-resistant Kapton tape. Experimenting with both 10K and 100K Ohm thermistors may be necessary to determine the appropriate probe for your device. The ones commonly included with thermometers are 10K with a stainless steel cover, concealing a thermistor inside.
Here’s the dual probe Thermometer I used in one of my system builds because it had an upper limit of 250F. You can get these in USB and 12v versions and simply use a power brick you have lying around. https://www.amazon.com/gp/product/B07WS11X45/
Here’s the thermistor that I used to replace the probes. I simply cut the wires and repurposed the connectors with these devices soldered in.
Here is the Kapton tape, sometimes referred to as the generic name of polyimide tape or circuit board tape or high temp tape. They are all the same, just look for the gold coloring. The tape is used in electronics and the adhesive is design to be able to survive very high temps. I’ve taped these directly to components that have reach 200c like Power MOSFETs and the tape has held although the device I was monitoring failed. But that’s why I was monitoring it.
On the subject of whether it’s an effective method or efficient use of electricity.
I found you’re idea to be very intriguing and a good example of ingenuity in repurposing an otherwise unused device in another way. If you’re you’re using it as a drybox, then I would think that it would be just fine. But few things come to mind.
Dehumidification without heat won’t effectively desiccate a spool. Water molecules need to be heated before they’re released into the air. Otherwise, desiccant bags would suffice.
Even with trapped heat, this device is unlikely to reach temperatures above 55°C, required for drying filaments like PETG, PC, ASA, and ABS, which are the ones you’d typically want to dry.
The enclosure’s nature will trap humidity, requiring occasional opening or providing egress for trapped moisture, which will also release heat.
While it may work, this device is likely inefficient compared to purpose-built filament dryers. Plugging it into a Kill-A-Watt style power meter to confirm electricity usage might be a good. Such humidifiers typically consume 250-300 Watts, compared to a purpose-built Sunlu S4, which holds multiple spools at 85 Watts. Power meters also have a cost calculator built in which can be pretty handy.
This is big. I recently put a humidity sensor inside my PrintDry while it was drying a filament, and to my dismay the dew point was much higher than outside the box. So, even with all the small holes in it, it still wasn’t exchanging air at an adequate rate. For such an overpriced filament dryer, I expected better.
I like how this guy did a DIY box that regularly pulses out the internal air:
