Outer Spool Desiccant Container - For use with Vacuum Sealed Bags

I had been storing my filament in plain old zip-lok bags with a small desiccant container in the centre of the spool for good measure. I recently decided to upgrade to vacuum bags, and using hygrometers to actually measure what the moisture levels are. This is when I ran into my first problem. When you apply a vacuum to a bag with a spool in it, and vacuum effectively seals off the centre of the spool from the outside of the spool, where the filament is. So you can put all the desiccant in the world in the centre of the spool, but it will do very little to keep your filament dry. You can measure this for yourself easily enough. Use 2 small desiccant containers and 2 hygrometers. Put one of each in the centre of the spool, and the other on the outside of the spool, and watch the readings over the next day.

So, I designed this desiccant holder specifically to load into the side of the spool, with a built in hygrometer so that I could better monitor all of the opened filament I have stored. I had the bright idea of printing these in "transparent" PETG so that I could see the state of the desiccant at a glance, but this is a very opaque type of "transparent".......

This desiccant container is different from many that you will see online in that it uses horizontal slots, rather than vertical. This makes the print time much faster, and your printer should have no trouble at all in printing the short bridges in this model. All of the prints you see in the photos were printed on a bone stock Ender 3 V2, so you should be able to print these on any printer with no problems.

I have provided several variants. One that uses a rectangular hygrometer, one that uses a round hygrometer, and one that has no hygrometer. These are just the cheap, ubiquitous hygrometers that you will find on amazon/ebay/aliexpress. The round hygrometer can be mounted in either horizontal or vertical orientation, but the rectangular hygrometer can only be mounted horizontally. All variants have small indented areas to suit a label, roughly 48mm x 14mm. I have also included an appropriately-shaped funnel to make is easier to fill.

If I put a dried spool of filament into a bag, then within 8-12 hours the humidity level will have dropped to around 10%, and that's where it usually stays. However, if the spool was not completely dry, then over time, the humidity level will rise slowly, over the course of weeks or months. Once it reaches 20%, I re-dry the filament in the drier for 6+ hours, and then re-bag it with fresh desiccant.

The lid simply snaps into place, and there are 2 small slots that allow you to easily remove the lid when needed

These were all printed using bog standard slicer parameters:
- 0.2mm layer height
- 2 perimeters
- 10% gyroid infill
- 3 bottom an 4 top layers