Upcycling for kids: Make Captain America’s Shield using MATH

All those who choose to oppose his shield must yield!

All those who choose to oppose his shield must yield!

J is seriously into superheroes right now, and I mean seriously, mummy I’m really serious about superheroes. Earlier this year he attended a party and was given a bright blue domino mask to bring home, which he immediately dubbed his ‘Captain America’ helmet.

Which is why we decided to make him a shield to go along with it, out of some cardboard boxes that I have been hoarding in the storeroom for such a purpose.

Instead of making a flat shield using a single piece of cardboard, we decided to give it more shape and depth by stacking the circles of cardboard on top each other to approximate the concave-convex appearance of Captain America’s circular shield. As a guide, we decided to use the shield design from this old copy of the Avengers comic.


  1. Large Cardboard Box
  2. String
  3. Pushpin
  4. Pencil
  5. Stanley knife or box cutter
  6. Glue (we used PVC glue for this)
  7. Red and blue paint (we used tempera paints for this project)


The red, white and blue'll come through

The red, white and blue’ll come through

1. Draw five circles of diminishing circumference sizes on the large cardboard box: To get the round circles, I had J draw the circles using a length of string with one end pinned to the cardboard and the other end tied to a pencil. Then we shortened the string by an inch and repeated the process five times. This is a great way to physically demonstrate the concept of a circle’s radius, diameter and circumference, as well as the relationships between them.

2. Use a sharp Stanley knife to carefully cut out each circle.

3. Use blue paint to cover the entire surface of the smallest circle. We used tempera paints as they are kid-friendly and washable, but you can get a much nicer, brighter colour using spray paint or acrylic paint, or by adding a layer of varnish or ModPodge to get a nice glossy finish.

4. Use red paint to cover the entire surface of the biggest circle and the middle-sized circle.

5. For the 2nd largest and 2nd smallest circle, we decided not to paint them white. This is because white tempera paint tends to disappear into the brown cardboard and you need many layers of tempera paint to get a good white finish, which will soak into the cardboard and weaken it’s structure. Instead, we peeled off the top layer of cardboard to expose the corrugated centre, in order to give it a contrasting texture.

You are my star

You are my star

6. Next, we drew a five pointed star onto the small blue circle. This is a great way to demonstrate the relationship between a convex polygon (in this case, a pentagon) and a regular star polygon! Using a stanley knife, J carefully traced the outline of the star, then peeled off the cardboard to expose the cardboard centre.

7. Using PVC glue, we glued the circles one on top of the other, making sure to line up the exposed pleats of the corrugated board so that the pleats are all in the same direction.

Double strap time

Double strap time

8. For straps, we cut out two long strips of cardboard around 5cm or 3inches wide and glued them to the reverse surface of the shield, making sure there is plenty of room to comfortably pass one’s arm through the straps. (If you want to be super fancy, you could use thick cotton or felt strips and space them further apart so that the shield can be worn like a backpack!)

9. Prepare the men to do battle!

3 thoughts on “Upcycling for kids: Make Captain America’s Shield using MATH

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