**What we need:**

Pen and paper, a calculator, a pencil, some rulers, a compass, a cutter knife, masking tape, glue, single or double wall corrugated cardboard, a work table and "patience".

**Introduction.**

Let say you wanna make a dummy of a dome that's 40 feet (40') in diameter and it's comprised of pentagons and hexagons, sort of like the same general layout in a typical soccer ball. Have a look at the 1st. picture. Although in this case, our soccer ball is cut in half (so to speak). That's why it's called a dome. Isn't it? We don't have 12 pentagons and 20 hexagons like in a soccer ball, but only 6 pentagons, 10 hexagons and 5 half hexagons.

**Signing Up**

## Step 1:

## Step 2: Some technical data and measurements,

The scale of our model is 1:48, which means, it's 48 times smaller than the real building would be. That's the same as saying that 1 foot (1') is equivalent to 1/4 of an inch (1/4"). This time we're gonna use centimeters (cm.) and millimeters (mm.). Since 1" equals 2.54 cm., a 1/4" equals 0.635 cm. So to make a long story short, in this project 1' is the same as 0.635 cm.

If we think of our dome as a structure, each edge (the line where the sides of two triangles meet) is equivalent to or represents a strut. We have in our dome three basic types of struts, A, B and C. Once we do the calculations and know the length of each strut, we'll be ready to rock & roll!

## Step 3:

These are the 3 strut factors: A = 0.34862; B = 0.40355; C = 0.41241. Any strut is equal to the dome radius, times the corresponding strut factor. So to calculate A, we multiply 20' times 0.34862. So we have 20' x 0.34862 = 6.98'. Then we multiply 6.98' times 0.635 cm. which gives us 4.43 cm.

**So A is 4.43 cm. in length**. Follow the same procedure for B and C. Although theoretically and according to strut factors, that’s how you come up with the length for A, B and C. From my experience in drafting these polygons and with the little trigonometry and geometry I know, I realized the real length for B is not 5.12, but

**5.02 cm.**Which means,

**“just a hair over 5 cm.”**So far you got A and B.

**Now you only have to calculate C and you’ll be ready to go.**

## Step 4: How to make the dome,

We want the cardboard that's inside the perimeter outlined with black ink. See drawing No. 3. Cut out the rest. Red lines indicate partial cuts. We just need the cardboard on those edges to bend and flex so we can finish off making our pentagon. You can see flaps or tabs (in green) at the base of each triangle. You need those to assemble your dome when you are done making polygons. To produce those, don't cut all the way through. Leave the thin layer of cardboard on the bottom. When you're finished making the first pentagon, it will look more or less like the one in the 2nd picture.

Note: I used "double wall corrugated cardboard" because that's what I had. 'Single wall' works as well.

## Step 5:

With what you've learned so far, you can figure out how to make the hexagons and half hexagons. Make all your polygons before you start putting the dome together. On top of the dome we have a pentagon. Use your imagination and the 1st picture as a reference, to figure out the layout of all the pieces in the model.

## Step 6: Suggestions and recycling,

If you make mistakes, good. If you make more mistakes, even better. If you can't seem to stop making mistakes, congratulations! "Success is 99% failure". Preferably, don't go to the paper shop and buy new cardboard or new boxes. Go talk to the guys at the supermarket or go to a hardware store and ask them when their next re-stock order is due. Tell them to keep some boxes for you. Have a good time and good luck!

## Step 7: About this instructable,

http://www.naturalspacesdomes.com/

http://www.domerama.com/domerama-geodesic-domes/