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How to Make a DIY Magnetic Building Set with Cardboard

How to Make Your Own Magnetic Building Set

Updated January 2021

*A big thank you to Sylvan Learning for sponsoring this post; as always, all opinions expressed are my own.

We have a new magnetic building set in the house and I am ridiculously excited about it.

It’s awesome. Seriously.

Want to hear all the reasons why?

  • The shapes are fun to play with and very creative.
  • You can build modern abstract sculptures in all kinds of fun configurations.
  • You can explore magnetic properties and build in ways that are not possible with regular building blocks. In fact, because of the lightweight cardboard, you can build in ways that are not possible even with other magnetic building sets.
  • All we used were cardboard, some glue, and a coil of magnetic tape. Even the paint is optional as the magnetic shapes look awesome with or without it.
  • This activity does a great job of exposing your kids to STEM. Sylvan Learning believes it’s important for kids to be exposed to STEM education because they are at the prime age for exposure, retention, and application. Incorporating STEM into fun activities like this magnetic building kit is a great way to start introducing your kids to STEM!

I know you’re going to want to make a set for yourselves, so I’ll show you how, with step-by-step instructions.

Make Your Own Cardboard Building Set

Make Your Own Magnetic Building Set with Cardboard

Children can explore magnetic properties and engineering with hands on learning and open-ended exploration. Building cool contraptions in an open-ended way helps kids become creative thinkers and problem solvers, which is vital to their future success and even the future of our world. If you are looking for fun ways your kids can learn engineering from the experts, Sylvan Learning offers a STEM focused program, the Sylvan EDGE. EDGE provide hands-on learning opportunities in classes focused on Robotics, Engineering, Coding, and Math Edge. These programs give students the confidence and skills to be successful in the future global workforce.

This post contains affiliate links.


*Save those boxes! Or stop by a store that’ll let you cart away their boxes. I went to an ABC Store for mine and found that the inserts to the liquor boxes work especially well for making these cardboard shapes as they are plain (no markings), not too thick, and somewhat pre-scored.

Making Shapes out of Cardboard for the Magnetic Building Set


  1. Cut your 3D cardboard shapes

    Use a utility knife to cut cardboard strips against the grain. (You want the corrugation lines to run across the width of the cardboard strip.) I cut my cardboard pieces about 2 inches by 10-12 inches.

    Fold your cardboard strip into your desired shape, such as a triangle, square, rectangle, or trapezoid.

  2. Glue your shapes together

    Now that you have your fold marks, run a line of hot glue along one edge of the cardboard strip, then fold the cardboard back into shape, holding the two ends together for 30 seconds or so until the glue hardens.

    Repeat with more cardboard strips and shapes. Make as many as you like! You can experiment with different shapes and sizes, too.

    Making Shapes out of Cardboard for the Magnetic Building Set

  3. Add your magnetic tape

    Apply your magnetic tape to the cardboard shapes. To do so, cut a section of the magnetic tape (perhaps 1-2 inches long depending on the size of the cardboard piece you’re applying it to). Bend the magnetic tape against its natural curvature to flatten it out, then remove the paper backing, and press the adhesive side to one side of the cardboard shape. You can add the magnet strips to one or all sides of the cardboard shapes as desired.

    Note :: If you know you want your magnetic building set to be colored, I suggest painting the cardboard shapes first, before applying the tape. We were figuring things out as we went and did this a little backwards.

    Adding Magnets to the Magnetic Building Set and Testing Them

  4. Try them out!

    Now, try out your new magnetic building blocks!

    Playing with the Magnetic Building Blocks

    We especially liked how we could build at an angle instead of just vertically. Because of the lightweight nature of the cardboard and the 3D shapes, we could build quite differently with this magnetic building set than with our magnetic tiles.

    Exploring Magnetic Properties with a DIY Magnetic Building Set

    Don’t you just love how sculptural this looks?! I actually really like the plain cardboard look of these, but we voted to paint our shapes. The painted ones look even better!

  5. Paint your cardboard building blocks
    We used tempera paint, but acrylics or BioColors would work too.

    Paint Cardboard Shapes for Building Set

    We had to be careful to paint around the magnets, which is why I recommend you paint your shapes first and then apply the magnets.

    Painting the Magnetic Building Blocks

  6. Build!

    Once the paint on your magnetic building blocks dries, build with them!

    Painted Cardboard Shapes for Magnetic Building Set

See what you can do with these lightweight, 3D, magnetic building blocks? So much!

Make Your Own Cardboard Building Set Square

Are you ready to build your own ridiculously cool magnetic building set now? I highly recommend you give this a try!

How to Make Your Own Magnetic Building Set

Thanks again to Sylvan Learning for sponsoring this post. As always, all opinions expressed are my own.

More Cardboard Building Ideas for Kids:

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How to Make a DIY Magnetic Building Set with Cardboard


  • Reply
    January 6, 2017 at 7:47 am

    We really enjoyed making these. Such an amazing idea and so simple. What kind of magnets did you use? Ours keeps peeling off even when they are hot glided.

    • Reply
      Jean Van't Hul
      January 6, 2017 at 10:46 am

      Hi Jessie. I’m glad you enjoyed making these! Did you bend the magnet strips back first to remove the curvature? That’s a key step with the rolls of magnetic tape. Even so, a couple of ours have since peeled up at the corners and need a dab from the glue gun.

      I’m wondering if a flat magnetic sheet would work? Or if you can get magnet strips that are not curved? Definitely something worth looking into…

  • Reply
    June 6, 2017 at 5:32 am

    I love it! Thank you so much I’ve been meaning to buy some magnetic tiles for my 3yr old daughter but they can be a bit pricey! This is a great opportunity for us to build and learn together, Thanks again!

  • Reply
    Susie @ Suddenlyonline
    October 31, 2017 at 10:23 am

    I absolutely love this idea and hope to have ago getting it organised for my girls! Both of my girls are extremely creative and I love the fact that this explores colour, texture, imagination and structure! Just great! Thank you for your inspiration!

  • Reply
    Ashley Covert Glaza
    January 19, 2018 at 12:21 am

    We started this project but didn’t have the magnetic tape so my almost 4 yr old got to learn how to use the hot glue gun today. He even incorporated a catapult into his structure! It was great fun! Thanks for the fun idea!

  • Reply
    April 1, 2018 at 5:07 pm

    I loved idea ….made a sample but the magnetic tape wasn’t strong enough to build upward. ????????

    • Reply
      Jean Van't Hul
      April 8, 2018 at 5:15 am

      I wonder if magnetic tape comes in different strengths? I know it comes in different widths, so probably the thinner widths would be less strong. Perhaps try again with a thicker magnetic tape?

  • Reply
    May 28, 2019 at 8:00 am

    Would you recommend cutting and gluing the shapes for the kids beforehand? Or what age would you recommend that could do this project right from the first step?

    • Reply
      Jean Van't Hul
      June 2, 2019 at 4:25 am

      You could do that, especially for younger kids. I’d say this would be a good project for about 5 and up.

  • Reply
    February 18, 2021 at 10:11 pm

    My almost 6 year old and I did this project today—one of my very favorite projects we have ever done! What a fantastic idea! I was a little sloppy with cutting and we painted them with kwik stix so they definitely aren’t as attractive as these, but the ratio of effort to immediate results was high, and we spent a long time making complex houses for small plastic animals. And our 2.5 year old loves playing with them too.

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