Foam D20, Easy Foam Project for Beginners



Introduction: Foam D20, Easy Foam Project for Beginners

About: Just sharing what I enjoy making.

This project is inspired by Random_Canadian’s "Plywood Icosahedron" project. Check him out, all his projects are interesting. I wanted to make a D20 that was big and able to be used as a dice but also soft enough to throw at people.

Step 1: Equipment and Materials


  • Ruller
  • Stanley knife
  • Pattern


  • Foam, from a camping/yoga mat
  • Glue contact cement
  • PVC Paint
  • Permanent marker

Step 2: Make Pattern

Make your pattern out of strong cardboard, so it keeps its shape. Then use your ruler to draw a line that is an even number. Mine was 8cm total, mark halfway ie 4cm, draw a line from the marked point at a 90-degree angle. Then start from one point of your first line and draw a line up to meet the second line, this line needs to be the same length e.g. 8cm as your first line. Repeat the same on the other side, to make an equilateral triangle. You can check the triangle with a protractor, the angle in the corners should all be 60-degrees.

Step 3: Cut and Glue

Pin your pattern down to the foam and cut out the triangle. Repeat 20 times, be careful not to cut the pattern. Try to make the cuts clean, the smoother the cuts the better the glue will hold. Glue the edges of 5 triangles together to make a point, work slowly to get them even. Continue glueing the triangles to your first point making more points till you have an icosahedron. Leave the glue to dry, give it an extra 10 to 20 minutes to let the bonds be strong before you move on to the next step.

Step 4: Paint

I did not have a primer but the paint seemed to have worked well without it. You could use spray paint, it is faster, I used PVC paint which gave it a nice plastic feel.

Paint one triangle at a time and try to give each an even coat, use a jar or cup to hold the D20 as you paint. Then let it dry before giving it another coat, I recommend a minimum of 3 coats.

Step 5: The Numbers

The easiest way to do the numbers is with a permanent marker, this gives you the ability to develop fonts and match colours. Take a D20 and follow the number pattern the basic rule of thumb is every corresponding side adds up to 21. Above are two different examples of two dice I did with two colours schemes and fonts (the Blue one was made by melting the seems together hence why it looks so rough).

Step 6: Enjoy

You can use your dice just as a display piece or you can throw it around. It is also durable enough to kick it.

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