How to Make Black Coral Out of Expanding Spray Foam - Scenic Artists' Tips and Tricks

There are some sets, such as the one for Rainbow Fish Musical that require coral as set pieces. There are many types of coral and various ways to to make the different types of coral. This blog post is about making black coral with expanding spray foam.

A drawing of black coral

First, despite the name black coral, this coral comes is various colors. These colors include red, green, yellow, white, and brown. Sometimes black coral is black, but that is actually rare.

In order to make black color for the stage set, you are going to need the following:

1. Flat surfaces like scraps of cardboard or cardboard boxes. If you don't have any scrap cardboard, you can buy Corrugated Cardboard Sheets.
2. Wax paper such as Reynolds Cut-Rite Wax Paper.
3. Craft wire such as BENECREAT Aluminum Wire
4. Expanding spray foam insulation such as Great Stuff Gap Filler
5. Spray paint such as Moneysworth & Best Brillo Leather/Vinyl/Plastic Color Spray Dye/Paint 12 oz, Black

In order to make the black coral:

1. Prepare as many sheets of cardboard that you want as many pieces of coral. If you do not have enough cardboard for all of the coral that you want to make, you may need to make the coral in batches.
2. Line your pieces of cardboard with wax paper. It is probably best if it is wrapped around the cardboard so it can be taped to the back, but do what you can.
3. Lay the cardboard flat.
4. Use the craft wire to make a general outline of the way you would like your coral to point. You can make various paths with the wire. Use pictures of black coral to lay out wire patterns generally copying those patters. Make sure to leave at least a little bit of a stem made from wire at the bottom.
5. Spray the foam onto the wire, making sure to follow the patterns of the wires and not spray it in other directions. Stop spraying when moving the foam from one piece of wire to another piece. Do NOT spray any foam onto the stem you made with the wire.
6. Let the foam dry on the flat surfaces. DO NOT MOVE THE SURFACES WITH THE FOAM ON THEM.
7. While the foam is drying, you can choose the different colors of spray paint that you would like to paint each piece of coral.
8. Once the foam is dry, remove them from the wax paper.
9. Take the pieces of coral outside or to a well ventilated area and spray the spray paint on them until well covered on one side, making sure to get into all of the little cracks and crevices.
10. Let the paint dry.
11. Once the paint is dry, turn the coral decorations over.
12. Spray paint the backs of the coral with your colors of choice, making sure to get into any little cracks and crevices.
13. Let this paint dry.
14. Once dry, you should have coral that has a stem that can easily be stuck into cardboard or Styrofoam on the stage in order to add to the scenery.

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