Cardboard stock sorting shelf – design and build

I was in the mood to build something with my hands, and I have been working on getting my garage organized into a functional space to do all sorts of maker-y things. I have a strong tendency to “collect” various materials that I think will be useful eventually. In order to keep my hoarder tendencies in check, I work very hard to cull my collections and make sure the material I keep is in usable condition and easy to grab and use.

Cardboard is incredibly useful. I built a paint booth recently, and I end up using cardboard for prototyping and boxes for shipping and also just holding stuff. But my collection of Good Cardboard™️ was not easy to reach and hard to take stock of.

Photo of garage with horizontal cardboard pile on top of shelving unit

I did some very rough sketching in Evernote to help visualize some ways to store and sort my collection, and ultimately settled on a simple design that I thought I’d be able to make. Most of the pieces could fit in a 40-inch wide rack, and the range of heights that were needed to stand the cardboard upright fit pretty well between 12 and 24 inches. Serendipitously, I had a scrap piece of 42-inch wide, 1/2-inch thick Baltic birch (probably) plywood that was a former closet shelf.

Sketch of shelf concept

With the sketch in mind, I jumped into Shapr3D and modeled the shelf with dimensions and got a good spatial understanding of how I’d build the shelf.

3D model of the shelf

Schematics of the slats, sides, and bottom shelf

I figured I could cut 2-inch by 42-inch strips out of the plywood sheet, and trim the pieces to fit the geometry. I broke the design down into a “cut list:”

Additionally, I figured I’d use a scrap piece of MDF board for the bottom shelf:

I put my circular saw to use on my saw track and mitre box to make all the cuts, which came out remarkably well. Due to a lack of options for fasteners, I used 1 1/4” #10 wood screws, which meant I needed another layer of material on the bottom shelf support joints. It ended up working out well because I used scraps from the cuts to add a little more surface to the bottom shelf support.

I pre-drilled all the screw holes (because the plywood will split otherwise) and did some creative pencil work with my square. Sadly, I was far too “in the moment” to take pictures of this part.

Photo of completed empty shelf sitting on top of my workbench

Photo of completed shelf filled with cardboard on the ground

I realized my design lacked a front stop to keep the cardboard from sliding off the front of the shelf, so I nailed my last strip of 42”x2” plywood to the front. Also, I ended up using the full depth of my scrap MDF shelf, so there’s an extra 5 or 6 inches of shelf that sticks out from the front. I don’t hate it, and it might be more useful if I end up hanging this from the wall.