Low Profile Silica Holder - Lid Mount

I live in an area where humidity will always be my nemesis. Even before having to consider keeping filament dry, a dehumidifier is always churning away in my office and attempting to keep the electronics happy.

After getting involved in 3D printing, I tried several silica bead holders to keep with my spools and dry boxes.  I have become a big fan of the “Ultimate Filament Dry Box” by Krieger but found that none of the silica boxes that I could find worked well for that. I will have to dry silica far more often that I will have to remove empty filament spools. Every silica box that I found would require me removing the 4 spools to recharge the silica, and that was a pain.  After searching in vain for the exact thing that I wanted, I decided that I would design my own. I hope that someone else will find this useful!

The design concept was this:

1. Be narrow enough to mount on the lid of my dry box without hampering the movement of the spools beneath it.
2. Be large enough to compensate for the humidity where I am.
3. Be removeable without having to touch the spools beneath it.
4. Be easy to open for refill/recharge.
5. Be versatile in the event that I change my mind later.

The outcome? This low profile silica holder.

The summary: This silica box comes in at just over 20mm tall (measured 20.25mm), and will use about 79g of filament if you print all the parts. It is 150mm in diameter, and will hold at least 150g of silica. (It will hold more if you print the alternate “bottom-no-mount” thereby removing the mounting hole that prevented me from putting in more than 150g with spillage). When both sides are screwed together, the risers in the middle make contact and should prevent any silica spillage through the mounting holes. It is designed to be mounted using a standard ¼" hex head bolt, because that is what I had the most of on hand. 

The obligatory note:  I found that the threaded top and bottom were hard to connect until I wiped just a little bit of silicon spray around the threads; that overcame the friction coefficient enough that it worked like a charm!

The top: “top-with-mounting-hole.stl” - I started with the idea that I would connect just the top of the silica box to the lid of the dry box. A ¼" hex head bolt will fit into the underside, and the 5mm spacer is designed to go between the top of the silica box and the lid of the dry box. This should allow airflow around the entire silica box; I have no idea if that is necessary or not, but it made sense to me to plan for it.

The first bottom: “bottom-no-mount.stl” - I started with this design. After I designed it (and before I printed it), I decided that I probably wanted to mount the entire box as a complete unit. I then designed…

The “better” bottom: “bottom-with-mounting-hole.stl” - This design also allows for a ¼" hex head bolt for mounting; in this configuration, the bolt goes through both pieces and mounts the entire silica holder as a single unit.

The accessory part(s): “spacer-5mm.stl” - This is designed to go between the top of the silica holder and the lid of the dry box. The size of the bolt that you need will vary depending on your particular dry box.

The accessory part(s): “plug.stl” - This plug is designed to fill the hole of the hex head mounting bosses. My theory was that I might want to be able to plug the mounting hole in the event that I wanted to use the silica holder dismounted. I have found this part to be fickle, depending on the filament. Several of them fit perfectly, and several wound up being too small after they were printed. I have not yet printed it in TPU, that may be advisable. You may also need to scale this up slightly depending on your printer/filament.

The completely useless accessory part: “cap-nut.stl” - My idea for this is to be a cap nut for the exposed hex screw. It has proven less than reliable, and I have always used a ¼" hex bolt.

The verdict? Well, that's for you the downloaders to decide. I hope that someone will find that this fits a need that they have and that it will be useful for them. I hope that you will post your makes, so that I can see how others are using. I hope that you will remix it if you find that it isn't to your liking. “I hope…” (subtle nod to a great movie, “The Shawshank Redemption”)