One last thing. I just ran across a post by a guy who prints nylon, and holy cow!, he may very well have the best system ever devised for keeping keeping his filament dry and ready to print at the drop of a hat. If I were a moderator, I’d nominate him for some kind of award.
Yes, I have been using those moisture indicator cards for decades. When I was manufacturing systems for industrial automation destined for tropical locations, part of our warranty process was that the customer had to perform regular maintenance and ensure that the interior desiccant was replaced periodically. The only way we were able to enforce this was by hiding moisture cards inside the case with a tamper-evident seal.
I have never stored a spool in a vacuum bag without a moisture indicator card. What I like about the moisture indicator cards is that they not only are reversible during the filament drying cycle—just include them along with the desiccant bag when you dry the filament—but unlike hygrometers, which only measure moisture at that instant, moisture cards register moisture accumulation over time. This is a fantastic way of ensuring that one can see if the filament truly needs to be dried. You could make the mistake I made early on by placing a desiccant bag inside a vacuum bag and thinking the job was done because the hygrometer registered low humidity. However, a moisture card tells a more accurate story if dried and stored along with the spool.
Warning: Lots of Counterfeit Moisture Indicator Cards on Amazon
But be warned, though. You have to test these cards each time you buy them. There are a lot of counterfeit cards on Amazon that are simply printed ink and don’t have any functioning indicator.
The best example, in my experience, was the cards that came with the Amolen vacuum bags. I complained to Amolen, and they sent me an entire new kit with a pump and all, but the cards were also defective, indicating that they are just a packager of this product and do zero quality control.
Here is Amolen kit that includes counterfeit cards from a brand called “Excellent Technologies”. Try Googling that term and see what you come up with. Typical Chinese ripoff that selects a fake name too common to find.
https://www.amazon.com/dp/B09G649KS7/
Here are legitimate cards I actually tested and verified. But don’t take it for granted. Test them each time. I simply use a measuring cup with water and steam it in the microwave.
https://www.amazon.com/dp/B09JBQM1DF/
Example of the Amolen cards when left inside a steam bath. Note that the indicator did not change at all. Amolen agreed and that’s why they sent me a replacement of the entire kit. I didn’t bother hitting them up a second time when those too turned out to be counterfeit, I just simply switched vendors.
Aside from doing a steam test, below is how you can tell if the cards are likely counterfeit before even attempting a steam bath.
Note the consistent appearance of the blue across the 10% - 60 % circles.
Counterfeit Indicator Cards
Now contrast with real moisture cards from Wise HC these came right out of the moisture sealed Mylar zip lock bags. Notice that the print black circles are very similar to the counterfeit cards but what you’ll also notice is that the color of the blue is very different in the real cards. I’ve since learned that you can’t get pure blue using indicator ink at the 10% mark. If it’s too consistent across the swatches, it’s likely fake like the “excellent technologies” cards in the Amolen kit.
Real Indicator Cards
The second unscientific test is to look at the back of the card for indicator bleed-through. The counterfeit cards don’t have this, the real cards show a gradual increase in chemical indicator.
Unfortunately, it’s hard to capture the difference in a digital photo but hopefully it will be visible enough in this image.
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Reporting back: Just a quick follow-up note here to close the loop on the cheap aliexpress TH sensors used in at least one of the storage solutions described earlier in this thread. If there’s enough interest, I can start a separate thread to elaborate. Otherwise, this will be my final post on this topic.
In short, I found a different Tuya app (free) that’s not overly invasive and which interfaces to the Tuya multi-protocol hub just fine. Therefore, it has no trouble collecting both the bluetooth and the zigbee sensor data. It does that continuously and graphs it, so that you have a nice picture of what is going on. Setup was easy. Of course, none of this would be worth mentioning at all except for the fact that the sensors are so insanely cheap on aliexpress that it’s almost unbelievable: bluetooth TH with LCD display can be had for $2-3, and Zigbee for $4-5. That price includes shipment to your door.
Is this a need-to-have? No. I’m guessing that the 30 cent humidity strips (above) would be sufficient for most people. Is it a nice-to-have? I would say l yes, because you can set tripwire humidity thresholds in the app and then just forget about it. i.e. Instead of you yourself being hyper-vigilent about your filament humidity, you can let the app be hyper-vigilent for you.
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I use the cheap filament bags that use a small suction pump, i got them from amazon and the seem to work great.
Reporting back: The Dry & Dry humidity indicator cards appear to work perfectly fine. All the circles went pink when exposed to 60% humidity, and they went back to blue when I put it into a sealed cereal container (above) with fresh desiccant.
Ironically, I’m not sure that I’ll end up having any real need for them though: they’re more granular than even the +/- 5-6% Tuya humidity sensors, and the digital sensors are just faster, not to mention showing trend data from the graphs.
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If you are not familiar with Sparkfun, you might want to check them out. They have an incredible amount of DIY components and also a huge source of related information.
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I recently bought 12 of these from AliExpress. I have them integrated (well started to) into Home Assistant running on a Raspberry Pi.
I threw one in my AMS to monitor conditions in there too.
I am also designing a stand to hold these up so I can read the LCD through the filament box.
Which type were the twelve that you bought?
By the way, thanks to both you and Olias I picked up one of the 25 quart gasket boxes from home depot today to try it out.
I see that there’s a cool dashboard hub out now called linknlink that works with homeassistant and gives you phone app access to all your home assistant sensors. Allegedly, it even manages to gain access to all tuya sensors of all types, not just the small subset that previoiusly could get co-opted by homeassistant.
Tuya sensors aren’t best-of-breed, but they sure do seem to be insanely cheap! And for this type of application, which calls for a lot of TH sensors, they set up very quickly and seem to be good enough.
Is there any update??
@NeverDie
Any update in regards to what exactly? We’ve covered a lot of ground in this thread.
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checked, thanks @NeverDie
Where do you get a container that size? I like that idea vs. putting everything in bags!
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Anyone here either found, created, or using any printed parts to make the most of this kind of cereal dry box? Maybe something simple along the lines of:
Or, alternately, something that pulls all the way out of it. Haven’t yet found a good example of anything simple for what that might look like:
There’s not a huge amount of wiggle room with this particular cereal box, so maybe I should have picked something a bit larger. On the other hand, the container is both unique and generic enough that the exact same model is sold not just by Praki, but also Skroam and others–the upside being that there’s more or less constant downward price pressure.
Even something as simple as:
except I don’t believe that particular one will fit a Praki. Since it doesn’t beneprate the plastic of the container, something like that would be ideal for keeping out moisture.
I’m not a huge fan of the bunker box, but it would be better than nothing:
https://www.printables.com/model/576531-supporto-porta-box-da-4l-filament-bunker
For what it’s worth, I used to use the vacuum bags but found the vacuuming part annoying, that was before the cardboard spindles which means the suction deforming the spindle.
These days I use 2-gallon food zip lock bags, with the original desiccant, wrap the bag over (it’s nice and big) then put the bagged spindle back into the original box.
I ordered straight from Amazon.
If that works for you, then great. However, I receive filament that’s vacuum sealed with a desicannt, and even fresh out of the box I often have to dry it before using it. So, for that reason, I’ve grown skeptical that replicating that will work for more than just the short-term. Easiest way to know for sure though would maybe be to put a wireless humidity sensor in there and track it over time. You can get bluetooth ones for as little as $1.50 that run off 2xAAA batteries. Those might be a good fit for you, since you’re putting them back in the original box where you can’t see a display anyway. Alternatively, you could simply weigh it and track the weight changes over time. That’s probably an even better way to measure it, especially if you have a descent scale that comes with calibration weights, like the one I’m using.
Anyway, reporting back. The best I’ve found so far is this one:
https://www.printables.com/model/396228-universal-single-spool-filament-dry-container
It’s bespoke for the Praki cereal container.
A few designs out there, like his one, for establishing a filament port that can be sealed when not in use:
https://www.printables.com/model/631707-universal-spool-container-port-20-pc4-m10
I may just be lucky then as I have only had to dry out one filament spool despite going through 100’s.
Are you in a dry climate? Where I am, at this very moment, the ambient humidity in my garage is 83%, 91% outdoors, and 64% indoors. Even running a filament dryer under these conditions is less than ideal. I may need to figure out some kind of two-stage dryer for situations like this. The first stage might condition the air intake enough for the second stage to then move ahead with a proper a normal dry cycle. Or maybe I just do drying when the ambient conditions are favorable and store it away for those times when it isn’t.
England, I just looked it up and is says annual average between 70% and 90%.
The stereotype of it always raining here is pretty true.
Well, that explodes my theory then.
I can’t fathom why it would be any worse here than there, but I can only deal with what’s directly in front of me.