Dolphin Drybox

(Sorry for the formatting. Old school HTML is more tedious than I want to mess with,)

A 3D printable drybox for your filament spools. Print right from the drybox. (All STEP files included)

Print with PETG only! For plastic spools only! (No cardboard spools, too much friction)

Assembly Instruction Video: https://www.youtube.com/watch?v=JpSp6HOc_Ys&t=8s

Designed to be a simple, cheap, ergonomic, and aesthetic filament storage solution:

-Print in 3 pcs, parts fully snap/glue together–no screw-type hardware required. (500g PETG filament for 1 Lid/Base Combo including supports + 40g for hanger bracket)

-Costs about $7/box including purchased parts (sealant strip, polycarbonate lens, M6 PTFE tube fitting)

-Hinges open from the front for easy access. Don’t need to keep sides clear, allowing for less footprint.

-Made to hang above the printer. (Though it can also rest on a shelf)

-It’s prettier than a tupperware cereal box!

How it works:

The idea is to keep the spool with its own dedicated drybox instead of swapping the spools out between storage totes and a drybox that you print from.

These dryboxes are designed to hang from a separately printed dovetail-style bracket using the connector on their backside.

I have a row of the included hanger brackets underneath my printing table for out of the way drybox storage and another row above my printer itself for the dryboxes that I’m actively using.

The current hanger brackets have a couple countersunk 1/4" or 6mm holes through them for mounting with equally sized “flat head cap screws.” But the STEP file for those brackets is also attached so you can edit how they mount or integrate them into whatever. As a side note, even if you don’t know CAD, you can create primitive solids and do simple boolean (solid part addition/subtraction) operations right from a normal slicer to create and merge parts if you want to attach the bracket to a model that way.

Tolerance between the male and female dovetail ends is 0.65 mm—no reason not to have the fit a bit loose.

Assembly (Dolphin Drybox Instruction Video: https://www.youtube.com/watch?v=JpSp6HOc_Ys&t=8s):

1. The lid prints in 2 pieces. Superglue them together, making sure the alignment slots are seated. I put a heavy book on it to hold it tight while the glue’s drying.

2. Press fit a 4.5mm diameter round silicone-rubber foam strip into the groove around the rim of the base. Those strips come in many sizes and materials. It’s very important to use exactly 4.5mm silicone rubber or it will not seal properly. (Amazon link in Bill of Materials)

3. The lid has a hole cutout to fit a 2” X 4.25” X 0.04” welding helmet lens. (Amazon link in Bill of Materials) It snaps into place. You can glue it to fully seal it, but if you do, glue it after it’s snapped into place. A water-like viscosity superglue works really well for this.

4. Snap the hinge together to attach the lid and base. Use firm steady pressure. It’s a tight fit. May need to trim the edges with flush cutters a little to fit between the hinge slots.

5. Screw a PC4-M6 PTFE tube fitting into the hole at the top. It’s self tapping. You will also need to ream out the through hole with a 2mm (or thereabouts) drill bit since small holes rarely print well.

Materials Required (Be sure to use exactly these sizes and material or parts will not fit properly--don't sub regular rubber for the silicone rubber)

-- 4.5mm Diameter Silicone Rubber Foam Strip. 60cm required, approx. $1/Drybox. USE EXACTLY THIS MATERIAL AND SIZE OR BOX WILL NOT CLOSE PROPERLY. https://www.amazon.com/dp/B0CW9RMD86?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

-- Welding Helmet Lens. 108mm X 51mm X 1mm. Low tolerance tight fit, needs to be this size exactly. $0.40/Drybox https://www.amazon.com/dp/B0C9HQ4SY7?ref=ppx_yo2ov_dt_b_fed_asin_title

-- M6 PTFE tube fitting. $0.45/Drybox. (Be sure to use 2.5mm ID PTFE tubing with it if you have a high speed printer like a P1S. The 2mm ID tubing is a lower tolerance, higher resistance tubing for Bowden style extruders such as an Ender 3.)

These were all printed on a QIDI X Max 3.

I included my OrcaSlicer file which was made for my X Max 3 using a 0.6mm nozzle, which is the maximum nozzle size that I’d recommend and also the actual nozzle size that I’d recommend—it shaves off so much time.

Slicer Settings Key Points (Mostly stock generic PETG settings):

-Uses 500g of PETG filament to print 1 Lid/Base combo + 40g of filament for hanger (any rigid filament would work)

-Use 0.6 mm or below nozzle. Mine was set to a 0.3 mm layer height.

-Use arachne wall settings at 60% minimum wall width (there are some small but critical features)

-Scarf those seams. Doesn’t hurt.

-15% infill and 5 wall loops and 5 top/bottom shell layers. Though for the most part, this model is thin enough where most of it will be 100% infill anyway save for a few spots on the base.

This will require supports. I recommend Organic Tree supports due to how cleanly they snap—which is especially important in the window area due to tight tolerance—set to a 35 degree branch angle which gives them a little extra reach to help eliminate superfluous tree columns.

I used Jayo, Kingroon, and Sunlu PETG filaments. They all worked very well and were right at $10/roll from AliExpress. Please use PETG. I do not know how the thin walls or compliant latch will work if you use a different plastic.

Potential Design Issues:

The layer lines aren’t going to be airtight. You can spray it with a sealant, but for what it is, I think that’s overkill. Just sprinkle some desiccant in the bottom and change it out when the color changes.

The viewport window is not sealed by snapping it in alone. What works for me is to snap it in place, then take some thin superglue and shoot it in the cracks. It’ll fill in the gaps underneath on it’s own with less risk of staining the viewport.

No hole for a hygrometer. For my needs, I didn’t want one. I wanted these to be simple and cheap filament storage so I could print a bunch of them. From what I tested, as long as the desiccant hasn’t changed color, it’s going to be dry as a bone in there.

The PTFE tube is an open hole leading in. Tape it or plug it. Might make a printable plug for it at some point.

No desiccant tray. I had one designed to snap in that dovetail hole in back, but it ended up being way more complicated that I assumed it was worth. Could make one to rest in the bottom, but it’s pretty easy just to sprinkle some loose desiccant in and pour it out when it needs to be dried. The KISS method.

No rollers. Originally, the base was a 2 piece print, but again, that overcomplicated things so I switched to making it print all in one at the cost of spinning roller bushings. It would need bearings to integrate them now, but tbh, plastic on plastic has almost no friction, so it would only be required for cardboard spools.

The spool rests might wear after extended use. This will happen. I don’t know if it’ll happen quickly enough to be an issue, but if it is, I can add a wear strip that’ll clip on there instead. For now, is what it is.

Design Notes:

If you remix this, you can shave off about 3 of the 10 hours that it takes to print to base by removing the graphics from the side. However if you leave the sides smooth, you will have ghosting effects from the interior ribs. So I do recommend replacing it with some kind of texturing.

The hole for the viewport in the lid measures 109mm X 52mm X 1.5mm (assuming perfectly square interior corners, which they’re not, so it’s a little less in reality)

The (polycarbonate?) welding helmet lens that I designed the viewport around measures exactly 108mm X 51mm X 1mm, and there’s not much tolerance to allow for a tight fit.

The sealing strip is a 4.5mm diameter “silicone rubber” foam cord. These types of seals come in many different materials and sizes; however, silicone rubber has the most compression which directly affects how well the lid closes and seals. Using another material would increase the gap between the top and bottom and best case, would make the lid harder to close. Worst case, wouldn’t seal or close. That’s a critical component.

The dovetail holder is tapered. I did that so as it seats down, it’ll fit tighter, and conversely, if it does fit tight, you’re not fighting it the whole way up. Best of both worlds: sloppy enough fit at the beginning to fit together easily and a tighter fit at the end for less wobble. However only two of the radii are tapered, not the whole dovetail itself.

The PTFE fitting was originally an M10, which is the size that allows a PTFE tube to fit completely through it. However, it ended up being difficult to thread the filament through that kind of set up, so the current one uses an M6, which is the size that stops a PTFE tube from passing through, and instead has a kind of funnel printed into the interior of the drybox to help feed filament. I notice it does wear a bit from the filament rubbing on it. Might be something to address in the future with a wear strip or a different design.

I put the PTFE fitting in top for enclosed printer related reasons (the filament runout sensor and the slot in the back that PTFE tube runs through) With the way my X Max 3 is, trying other orientations kinked the PTFE tube into a tighter radius than I was comfortable with, so a top feed ended up being the best for that. Also it allows the drybox to work while sitting flat on a shelf. Though, with enough height, a fitting in the bottom front would work really well for a tube that fed directly into the extruder.

Did not include a hole for a hygrometer. Seemed superfluous and just another added expense/drybox. From my tests, as long as the desiccant hasn’t changed color, it’s dry as a bone in there.

If you like this, please buy me a coffee to support these kinds of projects: https://buymeacoffee.com/pandatricks

Doesn't look like much, but an embarrassing amount of CAD hours and tweaking goes into it.