Cardboard Longboard Uses Quarter-Isogrid Structure

Skateboards are most typically crafted by hand, carved out of wood layered by care. However, many makers have sought to explore alternative techniques. [Technovation] decided to combine alternative materials and digital fabrication techniques to produce this attractive cardboard longboard.

The structure of the board was designed in Fusion 360, featuring a quarter isogrid design. The structure consists of stringers connected by ribs, all made of cardboard, with interlocking slots to hold everything together. 1/4″ plywood is then used to reinforce the truck mounts, and a top and bottom baseplate of 4mm acrylic is installed to protect the cardboard from damage.

The parts for the board are all laser cut, making production and assembly a snap. No glue is used, either – the structure is able to hold itself together perfectly well with its slotted construction. The team note that having a rider on the board does create some significant flex, but it hasn’t caused a failure in practice.

Skateboards are a popular maker project, and we’ve seen all kinds over the years. Modern manufacturing techniques are often brought to bear, or designs are created to solve tricky travel problems. Video after the break.

19 thoughts on “Cardboard Longboard Uses Quarter-Isogrid Structure

      1. I don’t think theirs a definitive answer, people who ride dancers might not consider my carver a long board, but putting “long board” wheels on a deck that’s not much if any longer than a short board doesn’t make it a long board.

    1. “Skateboards are most typically crafted by hand, carved out of wood layered by care.”

      Yeah, that one struck me, too. Sure, it can be done that way, but “most typically” the layers are coated in glue by a machine, molded with a machine, drilled with a machine, cut with a template and band saw, flush trim with a router and template, chamfer with a router, and sanded with a drum sander.

      Not to say all that isn’t labor intensive, but I’ve seen “crafted by hand… [with] care” decks, and that’s not the way that’s most typical.

  1. Reminds me of helicopter blades some decades ago.

    > No glue is used, either
    Well, other than the binder already in the cardboard.
    A fillet along the seams and a surface spray/brush done right should add significant strength. Hide-glue, with corn starch or flour filler (or ground up egg cartons) for the fillets, if you want ‘green’ bragging rights.

    Needs an additive in the hide-glue so it won’t release in the heat (or, i.e., get quick dis-assembly in a car trunk in the sun, a la exploding cello…). But such could ruin the ability of the cardboard to be recycled at the boards end-of-life.

  2. You mean, plastic longboard with cardboard glued in for looks?

    Adding those plastic sheets increases the stiffness of the construction tremendously. I’m not convinced that their model of the carbdboard mesh is realistic.

    1. “Sandwich cross sections are composite. They usually consist of a low to moderate stiffness core which is connected with two stiff exterior face-sheets. The high stiffness of the face-sheet leads to a high bending stiffness to weight ratio for the composite.”

      https://en.wikipedia.org/wiki/Sandwich_theory

      Basically, all the hoohah about isorigid grids is just that – fancy handwaving. What they did was to construct a sandwich panel. The point of the structure is that the neutral axis of bending is inside the core. The middle of the board is basically dead space – it carries very little of the tension, so it can be filled with very weak materials – all it needs to do is separate the surface sheets which carry almost all of the load.

      The stiffness of the board increases by the square of the separation of the sheets. With the plastic sheets held together from both ends by the trucks, the sheets could technically be separated with so many toothpicks or pieces of drinking straws and it would still work and carry a surprisingly large load.

      1. Correction: the plastic sheets seem to be held together all around by screws that compress the cardboard grid between them. Still, same difference. The load carrying capacity of the board has nothing to do with the fancy grid pattern.

        1. Does look rather impressive though, a little more work and it could be a very solid board.

          Worth noting an ‘even’ core does work to distribute loads better and so adds to the overall strength. However it seems to me the aim and what the grid pattern here achieves somewhat is greater strength than the plastic sheets for less added weight than using more solidly packed cores.

          They would be far better off trying an all wooden/cardboard build though so adhesives can be effective between sheets and fill grid if lightness is the aim. If you want to show off the over thick super light board then go for the edges – solvent weld a strip around the edge of the same plastic material – probably with some form of registration to hold the top/bottom layers at the right distance. Then perhaps solvent weld braces between the side edges at the truck attachment point. so the bolts can’t be over tightened and damage the cardboard as easily, and you don’t need to use ply – so you can see through even more.

          With the solvent welded edge strips sealing the cardboard ribs in that should be a heck of alot stronger enough to (probably) be practical, enduring and interesting to look at.. As it stands first puddle and its going to flop.

          Bring on Version 2!

  3. I’ve talked about making an aluminum honeycomb or aramid honeycomb skateboard using the cheap carbon fiber “tape” (3″ wide CF rolls) on the F1technical.com forums, but no one seemed to care…

    1. I definitely care! I’ve got a ~10 metre long 0.5 metre wide roll of uni-direction carbon pre-preg that was left over from a military aircraft modification and has now expired. An aluminium honeycomb skateboard is one of the projects I was definitely thinking of using it for.

  4. The construction is cool but the materials don’t really match skateboards. Decks should be durable, stiff, and springy. Wood and carbon fiber are prime choices. I’ve heard of CF over foam core too (similar to surfboards).

    Do people still make foam molds for wood decks? I saw that in the early 2010s but never on HaD.

  5. Wow, no strength to that board at all. His feet are only over the trucks, yet you can see how much it warps downward. And, as others have mentioned, sandwich-structured composites are not a new thing, even for skateboards. My brother’s friend had one in the ’80s. Had he glued the cardboard and the face sheets, I bet it would actually be durable.

  6. even easier: take your cardboard, lay it flat in strips, soak it in resin, vacuum bag it, press it in a curved mold until it cures, trim and your “cardboard” deck is now a natural fiber composite. If there’s unwanted flex, more layers of cardboard and perhaps a different resin formulation :)

  7. So, I don’t want to be that guy… But will be anyway
    I have a lot of experience with cardboard and it looks like they have made the components with the flutes in the wrong direction.
    The structure would be many times stronger if they had the flutes running vertically.
    They also shouldn’t have cut the cardboard, but had the diamond points back to back.
    Rather than have a separate piece to lock the pieces together, they should have relieved the diamond pattern into the surface of the acrylic.

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