How to Create a Cuboctahedron Mould and Triangular Prism Core Plant Pot Cast!

This is an Instructables on how to make a cuboctahedron mould and triangular prism core plant pot cast.

Step 1: High Impact Polystyrene Sheet

Get a sheet of High Impact Polystyrene (HIPS).

Step 2: Sticking Paper

Glue 2 sheets of A4 paper to the HIPS sheet using a glue stick.

Step 3: Drawing Squares

Get a pencil and a 45 degrees set square and draw 5 squares 6cm by 6cm (length & width) starting from the bottom left hand corner of the HIPS sheet.

Step 4: Drawing Triangles - Part 1

Next, get a compass and set up the compass 6cm wide like this.

Step 5: Drawing Triangles - Part 2

Now, place the metal tip of the compass on one corner of the paper or a square and draw a line and then do the same on the other side 6cm apart like this. Do this 8 times to create 8 intersecting points to draw the triangle shape.

Step 6: Drawing Triangles - Part 3

Then draw 2 lines from one point to the other to create the triangle shape like this.

Step 7: Drawing Small Triangles - Part 1

Now, set up the compass that is 4cm wide like this.

Step 8: Drawing Small Triangles - Part 2

Now, place the metal tip of the compass on one corner of the paper and draw a line and then do the same on the other side 4cm apart. Do this 2 times to create 2 intersecting points to draw the triangle shape.

Step 9: Drawing Small Triangles - Part 3

Then draw 2 lines from one point to the other to create the triangle shape.

Step 10: Drawing Rectangles

Now, draw 3 rectangles that have a length of 12cm and a width of 4cm using the set square.

Step 11: Cutting Out Individual Pieces

Once all of the shapes are drawn, cut out the shapes using a pair of scissors.

Step 12: Forming the Triangular Prism Core - Part 1

Now get the 3 rectangle pieces and the 2 small triangle pieces and tape them together using cellular tape to form the net-shape like this.

Step 13: Forming the Triangular Prism - Part 2

Then, fold the pieces to form the triangular prism shape by taping them together. Make sure all of the sides are tightly sealed with cellular tape.

Step 14: Forming the Cuboctahedron Mould - Part 1

Get the 5 squares and the 8 bigger size triangles (6cm) and tape them together to form this net-shape.

Step 15: Forming the Cuboctahedron Mould - Part 2

Then, fold the pieces one by one and tape them together using cellular tape to form the shape of a cuboctahedron like this.

Step 16: Preparing the Plaster to Cast

Once the cuboctahedron mould and triangular prism core are made and all of the sides and corners are sealed, get a bucket, spatula, and casting plaster.

Step 17: Preparing the Plaster to Cast

Add 2 cups of water and 3 cups of plaster to the bucket and mix using the plastic spatula until the water and plaster are mixed well.

Step 18: Pouring the Plaster Into the Mould

Then, pour all of the plaster into the mould and gently hit the sides of the mould so that the plaster smooths out and removes any bubbles. Then place the core in the middle of mould and push downwards so that the core almost reaches the bottom of the mould, leaving about 2cm of space between the core and bottom of the mould.

Step 19: Wait for the Cast to Harden

If more plaster is needed repeat the previous 2 steps. Then, leave the plaster to dry overnight for a few days.

Step 20: Removing the High Impact Polystyrene Structure

Once the cast has dryed after a day or so, remove the high impact polystyrene structure from the cast by carefully cutting the tape using a cutter knife and remove the core by pulling it out using your hands.