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filament vault

Posted: Sat Jan 06, 2018 10:18 pm
by jferguson
After discovering that opened filament stored in the garage absorbed moisture and produced crummy (term of art) prints, I diced around with how to keep it dry. As always most of the solution was readily available at home depot. I had read that a container with a 25 watt incandescent light bulb would do the trick, but that was too simple for me. I wanted to know what the humidity was in the 'vault'.

I bought a 'homer' bucket, a screw in lid, a standard light bulb socket and a 25 watt appliance light bulb.
I bought a "Hurrah" Feather micro controller (has wifi built in), a temp-humidity sensor, a Feather relay (for turning lightbulb on and off), and a Feather OLED display from the good lady at

I modified the Arduino code which Ms Ada publishes on her website so that I could read the temp and humidity and turn the light on and off from anywhere with internet access. And, Voila, it works. It can handle 3 spools at once and maybe if I replaced the desiccant tin with the little bags, I could get a fourth spool in there. It was able to restore a spool of ESun PLA to it's original condition (or close enough) which had been producing really ugly blistery prints.
The humidity sensor has a +/-3 percent accuracy, so i cannot know the specific humidity in the container. The light-bulb is sufficient to get the temperature in the bucket up to 115F. At 115F the relative humidity will get down to less than 5% which means something like 10% at normal room temperature. Cost was something like $70 for everything. it is controllable via web site where I constructed a 'dashboard' for viewing the humidity-temperature data stream and have a switch for turning the light-bulb on and off.

I'm probably going to add some automation to the code so that the bulb will come on for 24 hours anytimg the humidity in the container rises above 15%

Re: filament vault

Posted: Sun Jan 07, 2018 4:51 pm
by Phil
Another thing you can add is three/four John Guest fittings in the lid. You can have tubing run from the fitting directly to your printer, and when not using a strand of filament, you can cap off the tube to prevent outside air from reaching the container. ... -fittings/ ... TVMU&psc=0

Re: filament vault

Posted: Sun Jan 07, 2018 5:52 pm
by jferguson
Sounds like a pretty good idea. I was completely blown away by how well this thing restored what had been a reel of "PLA gone bad" to as good as it was when I took it out of its original wrapping. It appears to take less than 24 hours to get this result. The relatively low cost of design mistakes using 3d printing has probably increased the number of iterations on my projects, but because of the complexity of the designs, I may go a couple of weeks between printing sessions so it makes sense to return the reel to the vault during the offline interval.

I suppose I'll grow out of this, but right now it's so neat to be able to dial up the Adafruit dashboard, and see what the temperature and humidity is in the vault and then turn on the light bulb if I think it needs to be jogged a bit. I don't have any idea how the desiccant canister is going to hold up. So far there is no evidence that it is loading up. I could do this from anywhere in the world -- almost.