Update:

Wow - its been close to a year since I posted this! The build has taken longer than I had hoped, due other responsibilities but its coming along nicely. I have attached some photos showing its current state, as well as photos of the hinges in use. The door is offset from the cabinet to allow room for a 3/8" weather seal, as well as allowing the outer edge of the door to swing “in”, so it will not need additional room on the side of the cabinet with a normal, outside hinge such as your refrigerator door.

You'll notice I have a second set of rods in the back of the left side to support the filament - this was due to a manufacturing flaw - I was so focused on accounting for the largest spool I had, I forgot to account for the tray I wanted to go under each set of rods. As a result the smaller set of spools would sit just low enough to cause an issue. I printed some adapters to add to the top of the existing ones, and added a rod there. This in effected reduced the distance, raising the spools the 1/2'" needed for clearance.

Introduction

This is actually my second attempt at a filament storage solution. The first one involved hangars and rod system, attached directly to the wall, where I could slide filament back and forth as needed and load it into my Ender system. It would have also worked well with a variety of MMU solutions as all the filament was supported by ball bearings.

Unfortunately, the system could only hold 40 rolls of filament and I had outgrown it before I had even completed the project - so on to attempt #2!

A free-standing cabinet that could not be more than 4 ft. wide, had to fit through my doorways (so less than 6 ft. 6 in. height), and preferably no more than 1 ft. deep if possible, so as to limit how far it reached into my available office space. All this plus had to be stable, on wheels, with doors and the ability to seal it against humidity.

I had never worked with Melamine, but I knew some of its properties would solve a lot of issues for me right out of the gate, such as its surface being sealed against humidity. Sure I popped a whole bunch of wholes into it right away, but that's a problem easily solved with more plastic and silicone sealant.

As stated in summary, please note this is a work in progress and some materials and designs are subject to change as I progress through the build.

The complete instruction guide on how to assemble, including drill spacing and sizes, will be written up once the unit is complete.

Printed Parts

Cabinet Rod & Tray Supports

28x: Outer Rod Support - Main (PETG)
14x: Inner Rod Support - Main (PETG)
21x: Inner Rod Support 1 (PETG)
21x: Inner Rod Support 2 (PETG)

Mating of Rod Supports

All 28 of the “Outer Rod Support - Main” are mated to 14 of the Inner Rod Support 1 and 14 of the Inner Rod Support 2

All 14 of the "Inner Rod Support - Main" are mated to 7 of the Inner Rod Support 1 and 7 of the Inner Rod Support 2

Desiccant Tray (per row/col, 6 rows x 2 columns: 12 total trays)

Note: You don't need a desiccant tray for every area. I am still testing but am anticipating a tray every other row in a vertical sense would be fine.

Also, the Plug I found worked best printed in TPU at 97% its size for a snug but easy to grip piece.

1x: Desiccant Tray 1 (left side) (PLA)
1x: Desiccant Tray 2 (middle) (PLA)
1x: Desiccant Tray 3 (Right side w/fill hole) (PLA)
1x: Desiccant Tray Plug (TPU) - Print at 97%
1x: Desiccant Tray Cover 1 (left)
1x: Desiccant Tray Cover 2 (middle)
1x: Desiccant Tray Cover 3 (right)

Rod Support Instructions

The rod supports are meant to slide into a 1-¼" hole, and one side will nest inside the other, making a nice close fit for a 1" OD rod or tube). I would recommend using a fostner bit as a hole saw tends to wobble too much and generate an irregularly shaped hole, or one that at allows for much too much play.

The parts are designed for a “snug” fit. They do include a hole for passing a bolt through to tight down if needed, but I found that due to their typical usage a simple silicone sealant is good enough to provide the friction so they wont move once installed.

Complete Cabinet BOM

Cabinet BOM

The cabinet build consists of:

3x: 1 ft. x 6 ft. x ¾" Melamine Shelf (sides, and middle brace)
2x: 1 ft. x 4ft. x ¾" Melamine Shelf (top and bottom)
1x: 4 ft. x 6ft. x ½" Melamine Panel (backer board)
2x: 2 in. x 4in. x 4ft. stud
2x: 2 in. x 4in. x 1ft. stud

1 Tube Silicone Sealant

50x: 7 mm x 50 mm Highpoint Confirmat Screws, Pozi-Flat Head, Zinc Finish
3x: 170 Degree Concealed Hinge Frameless Cabinet Hinge Hydraulic Adjustable Installation Soft Closing, Full Cover

(yes the hinge was overkill, but there is a method to the madness)

4x: 2" locking caster wheels, 150lb capacity (total of 450lb)

Silica Desiccant Tray BOM (per tray)

PLA and/or PETG. I used both. PLA for the base, and PETG for the cover (for higher transparency value). Eventually I will be adding a heater to the system, but until then PLA is what I have on-hand for the base and I can always reprint later

40x: Steel Thread Rolling Screw for Plastic, Black Oxide Finish, 82 Degree Flat Head, Star Drive, #4-20 Thread Size, 1/2" Length

1 lb. of reusable silica desiccant beads (per tray, really up to you how full you want the trays)

2x: 6061 Aluminum Round Rod 11.9" Long 1/4" rods to give the tray support since its printed in multiple pieces
(I used the following):
Amazon.com: 6061 Aluminum Round Rod 11.9" Long 1/4" Diameter Solid T6511 New Lathe Bar Stock for DIY Craft making-10 Pieces : Industrial & Scientific