Cardboard Chair (Yes, It's All Cardboard)

Making a chair can be difficult, but making one out of cardboard is even more challenging. Cardboard is very easy to find, so making this chair is a nice thought, but actually creating it takes a lot of time and effort. When laying flat, cardboard will bend, which is useless for a chair, but when standing vertically, it is very strong and sturdy. And when cardboard is bent into a triangle, it can also be strong. These simple shapes and designs all come together to form the basis of this chair!

To make my chair, I decided to have a combination of vertical sheets of cardboard and triangles. The triangles are mainly used to support the weight of a body, and the vertical sheets are used to keep the whole structure sound underneath the triangle supports. I encourage you to create your own design of a chair, so I will try to avoid publishing my entire, complete design (also some schools have this as a project, so I won't post the exact information on my chair so students can't copy this).

Supplies

You will only need a few basic tools:

Lots of big sheets of cardboard
Hot glue (a lot too)
Something to cut the cardboard (like a box cutter)
A straight edge (like a piece of wood)
Something to measure with (like a tape measure)
Something to write with (like a pencil)

Step 1: Planning the Dimensions of the Chair

Before making your chair, you got to plan out how large you want your chair to be, like the distance from the ground to the seat, the depth of the seat, the length of the backrest, etc. So for me, I just measured parts of my body to create the perfect ergonomic chair.

Here are some crucial measurements needed for this chair:

The height from the ground to the seat --> the length from your foot to your knee
The seat depth --> the length from your knee to your behind
The seat width --> the width of your behind/hips
The height of the backrest --> the length from your behind to your shoulders
The height from the seat to the armrests --> the length from your behind to your elbow
The width of the armrests --> the width of your forearms

Obviously, you don't want your chair to be exactly the same size as your body. You would want it a little bigger in every direction so you can sit comfortably in your chair. When resizing your measurements, keep in mind to make the numbers nice and whole so manufacturing this chair will be a smooth process.

Step 2: Planning the Design of the Chair

Now that you have your measurements, you should now start thinking of how you will create your chair design. For my chair, I made triangle supports that sat on top of vertical panels of cardboard, which was held in place by cardboard distance spacers (which is all covered up by a curtain of cardboard). Generally, the vertical panels were like the parallel lines of a grid, all held together by the triangles.

Instead of what I did, you can simply just create a grid pattern, or you can stick a seat on top of some triangle pillars, or something else. But you should draw all of your ideas out.

Once you have your idea, you need to plan out each individual cardboard sheet shape. For example, each side panel of my chair is basically the outline of a chair with triangle cutouts. That's one sheet done. Each triangle is basically a piece of cardboard folded into four equal sections (the last two faces are glued together to make the structure strong). There's another sheet done. And you just have to keep doing that. Don't forget to consider the thickness of your cardboard into your planning. You don't necessarily need thick cardboard. My cardboard was 3/16" thick. Just make sure you keep that in mind when creating your design.

What also helped me was creating a CAD model of my chair. I created all of the flat parts and then combined them into an assembly to make sure that what I was creating worked out and made sense. I'm not publishing any of my CAD models or drawings, but you can imagine that it's just a bunch of basic, flat drawings of each panel of cardboard pieces.

If it helps, you can also create a smaller scaled model of your chair. I did this, but it was time consuming. If you don't have time, skip this, but I highly recommend this step. Not only did I test out my design, but I also practiced the manufacturing techniques I was going to use, such as: cutting a straight line in cardboard, the best locations to put hot glue, and the order of assembly.

Step 3: Manufacturing Your Chair

So this is the hardest part of making a cardboard chair. If you're this far, your chair looks good on paper. But when you start cutting into the cardboard, everything changes. Cutting cardboard perfectly is really difficult, so these imperfections will make the manufacturing process stressful, so be prepared. I won't tell you exactly how I made my chair, but here are some useful tips.

Use a template. Your chair will probably have some pieces that are all the same (for example, my design has 6 really long triangles). With these pieces, I created a really good first piece to use a template for all of the following pieces, which saves you a lot of time measuring and stuff like that.
Glue last. Cut all of your pieces out first and put them together dry to make sure that everything works out and is perfect. Once you had your little test run, then you can start gluing your pieces together.
Don't rush. If you get tired, take a break and come back to it. If you start to get impatient, then your cuts will get sloppy and everything will be slanted and your chair will collapse from under you. Take your time so your chair will actually be usable.
Check your cardboard. Some sheets of cardboard aren't completely flat, so if you are planning on using vertical supports, don't use the bad cardboard for these. You don't have to throw away these warped sheets of cardboard. Just use them for pieces that aren't crucial. Use them as cover pieces to finish off your chair.
Have fun! If you don't, this whole process will be torturous.