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July Newsletter: Rainbow Icosahedron

Four Icosahedra and a Pentagon Bowl sitting on a white plastic board. One Icosahedron is totally clear. Two Icosahedron are heavily colored with transparent primary or secondary colors. The last Icosahedron is thinly colored with a washy effect. A clear pentagon bowl sits adjacent.

It’s Summer!  Watercolor Wildflowers Monthly Newsletter here featuring a rainbow Icosahedron.  What’s that?  Read on.

Resinart nightlights and lighthouses on display in a darkened room. Colors range from red to yellow to aqua to green and blue.
Glowing nightlights and lighthouses on display in a darkened room. Colors range from red to yellow to aqua to green and blue.

This month’s winner of a Planetary Nightlight is Robert at RobertLovesPi.net, a very cool blog about polyhedra and tessellations. Subscribe to my newsletter for a chance to win!   

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Customer Newsletter      July 2025

Rainbow Icosahedron in Resin

Exploring the intersection of art and science, the Icosahedron embodies principles of symmetry and balance. Its structure has fascinated mathematicians and artists alike, inspiring countless creative projects. At my studio I’ve kept going with the Icosahedra idea (plural of Icosahedron). Its like a geodesic dome but all the way ’round. The trick is finding best way to assemble these beveled equilateral triangles.  Mathematically, it will fit. The best outcome requires  precisely made 60° resin triangle chips of equal thickness. Beveled edges of 15° are sanded on my vertical belt sander.

Alcohol Pigment

I’ve found alcohol pigment is a good way to color the hard resin after the sanding and clean-up. Primary and secondary 3″ colored triangles are distributed evenly.  Each Icosahedron has 20 triangles. So I make 3 red, 3 blue, 3 yellow, 3 violet, 3 orange, 3 green (rainbow) and then 2 clear triangles.  The coloring may be simple but its the best way to avoid muddy (tertiary) color accidents.

Alcohol pigment effectively colors the cured resin post-sanding and cleanup. Each Icosahedron comprises 20 evenly distributed colored triangles. The distribution includes 3 red, 3 blue, 3 yellow, 3 violet, 3 orange, 3 green (rainbow), and 2 clear triangles. This simple coloring method helps me prevent undesirable muddy colors. Muddy colors are the mixing of less bright, less clear, tertiary colors by accident. I want these Rainbow Icosahedron to be mesmerizing and fun to look at.

colorful display of Icosahedron equilateral triangles in rainbow colors laid out on a white board
Equilateral triangles to be used to make a three-dimensional Icosahedron

How to Assemble an Icosahedron in 20 Pieces

I found the best way to assemble the Icosahedron from studying the unfolding diagram. Unfolding diagrams show what elements make up a three-dimensional object (flattened pieces). Turns out you start with the middle.

colorful pentagon with triangular elements in primary and secondary colors forming a star and another pentagon
This is the inside of two-thirds of an Icosahedron. The bottom triangle edges of the crown are visible first, then the inside of the alternating crown triangles, then the pentagon top.

The middle band of 10 triangles up then down should be taped edge-to-edge on a smooth flat surface with 1/2″ masking tape. Carefully raise the chain of triangles onto its side and curl it into a circle. Tape that last triangle to the start of the circle. I carefully add more masking tape, tightening and holding the triangles more firmly together. This makes a crown where curiously one triangle tips inward 5° and the next triangle tips outward by about 5°.

I form the top pentagon as five triangles pointing into the middle and pulled up at the center. Starting these shapes with masking tape saves a lot of frustration. Add the top to the crown. Match, fit and tape edges tightly together in all directions.

The bottom pentagon goes on the same. If made with near-exact equilateral triangles, then a tight fit can be achieved. The taped pieces are glued together carefully with tiny resin welds between tape. 

Two heavily colored Icosahedra resting on a white plastic board in the sunshine. The image cast from light through the Icosahedra appears on the white plastic board.
Two heavily colored Icosahedra resting on a white plastic board in the sunshine. The image cast from light through the Rainbow Icosahedra appears on the white plastic board.
Colorful pentagon shaped Icosahedron sitting on a sunny window sill. The equilateral triangles are colored in a washy technique and they are colored red, blue, yellow, purple, green, or orange.
Colorful pentagon shaped Rainbow Icosahedron sitting on a sunny window sill. The equilateral triangles are colored in a washy technique and they are colored red, blue, yellow, purple, green, or orange.
Four Icosahedra and a Pentagon Bowl sitting on a white plastic board. One Icosahedron is totally clear. Two Icosahedron are heavily colored with transparent primary or secondary colors. The last Icosahedron is thinly colored with a washy effect. A clear pentagon bowl sits adjacent.
Four Icosahedra and a Pentagon Bowl sitting on a white plastic board. One Icosahedron is totally clear. Two Icosahedron are heavily colored with transparent primary or secondary colors. The last Icosahedron is thinly colored with a washy effect. A clear pentagon bowl sits adjacent.

Finishing the Rainbow Icosahedron

All of these get a clear resin finish.  I’m trying different pigments and transparency ideas.  And I’ve got some one-way mirror film that will create an infinity effect.  You’ll see forever next month as well as some food-safe stylish Pentagon Bowls!

CALL OR VISIT MY STUDIO 5069 Leavenworth Street Omaha, NE 68106 (402) 943-7516

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