TPU Seal for Round Filament Case

Why I made this model

I love the round filament box that Torger created. I have printed almost 30 of them at this point. I found, however, that the seal against humidity wasn't enough for my needs. Even with as much desiccant as I could fit within the spool hub…frequently humidity would still be over 30%. I like to keep humidity under 20% (preferably closer to 10%).

So I created this TPU seal to do just that!

Who is this model for?

If you have printed the lid variation with the “slot” or grove where the author recommends to use a piece of TPU and that seals well enough - I suggest ignoring my model! If what you have already works, then my model may be redundant or unnecessary for you.

My model is for people who need more sealing than the out of the box model provides.

Printing Notes

This model requires TPU. I haven't tried the “TPU for AMS” yet, and don't know if that will work. I have heard it is rather hard for TPU so it may be too stiff. But if anyone tries it and can report back if it works well, that would be appreciated!

I printed my set (about 10 so far) using my go-to PEI Textured sheet. TPU sticks too well to this sheet IMO and trying to peel such a delicate model of the sheet, resulted in several torn prints :-(. So don't just go trying to grab it off the bed, or it could tear.

There is no denying this is a very delicate model. Most of it is only about 0.8 (two perimeters) wide.

Maybe another sheet type would work better. I ended up using some baby powder/talc and applying a thin coat on the bed using a paper towel. If using PEI textured sheet, give the talc/babypowder hack a try - it isn't perfect, but definitely helps.

If it is still to stuck to the build plate, then you may have to use the scraper that came with the printer (see photo) to carefully pry up an edge and then run the scraper around the perimeter to break it free. Of course, do this carefully so you don't scratch the PEI or bed surface.

Fitment Notes

So far it seems that the (nominal) 0.8mm thick version is working well. Time will tell if they hold the seal, but after a few days my spools are down from an average of 34% RH to around 18% which is a big improvement. I experimented with even thicker versions of the gasket but those were too hard to get onto the box. But if you want me to try to develop an even thicker version (that still can be fitted and removed easily enough) then let me know.