Intro: Creating a Paper Weight

In this instructable, you will learn how to make a paper weight out of plaster by creating a mold and a core out of high impact polystyrene.

STEP 1: Step 1: Preparing the Materials

Gather a sheet of high-impact polystyrene and a piece of A4 paper to begin with. Glue the A4 paper onto the high-impact polystyrene, making sure to put glue on the whole piece of paper to avoid it falling off. Glue the paper into a corner of the HIP to waste as little as possible.

STEP 2: Step 2: Drawing Shapes of the Mould

Use a 45 degree set square and pencil to draw squares and triangles onto the paper that is glued onto the HIP (high impact polystyrene). Draw a 6 cm square with the set square starting in the corner of the A4 paper to waste as little paper as possible. Using as little space as possible, draw 4 more 6 cm squares on the paper.
Next, if you have more space on the paper, draw a 6 cm line and mark the half point of the line (3 cm)
Draw a 10 cm straight line up from the 3 cm mark.
Measure 6 cm from one end of the line to the line in the middle, and repeat this for the other end of the 6cm line. The triangle should look like the one as shown above. Repeat this process to make 8 triangles in total.
If you run out of space on the A4 paper, glue another piece onto the sheet of HIP.

STEP 3: Step 3: Cutting Out the Shapes of the Mould

Cut out all of the squares and triangles using a pair of scissors
Make sure to follow the lines exactly to avoid gaps in the final mould
Once all of the triangles and squares are cut, check that there are 8 triangles and 5 squares in total.

STEP 4: Step 4: Putting Your Shapes of the Mould Together

Create the shape with the squares and triangles that you cut into the shape that can be seen above.
Tape all of the sides together that are touching after you have created the shape above.
Fold the pieces where they have been taped and make the shape into how it looks above (final mould).
There should be a square at the bottom of the mould.
If there are parts that are not secured to anything or that would cause wet plaster to leak, tape them tight.
Ensure that there are no gapes between squares or triangles. Your mould should like like the one above.

STEP 5: Step 5: Measuring and Drawing Shapes for the Core

With a new sheet of HIP and an A4 piece of paper, repeat step 1
Repeat the process used to create a triangle from step 2 except make the triangle base 5 cm as well as the height.
Measurements can be seen above
Repeat the triangle process above 3 more times
There should be 4 triangles in total

STEP 6: Step 6: Cutting the Shapes for the Core

Cut out the 4 triangles with scissors
Be sure to follow the lines accurately
Check that there are 4 triangles in total

STEP 7: Step 7: Taping and Securing Edges of the Core

Line all of the edges of the triangles together
Tape the edges that are touching together
Fold the pieces so that it forms a pyramid shape.
Tape any loose corners or gaps that will allow plaster to leak through.

STEP 8: Step 8: Mixing Plaster

Use two parts water and 3 parts plaster to create the plaster mix.
In a bucket, pour two cups of water and then add 3 cups of plaster.
Mix the solution until the dry plaster cannot be seen and so that the consistency isn't thick, nor too runny/thin.

STEP 9: Step 9: Casting Plaster

Pour the plaster into the mould until it is 3/4 full.
Lift the mould and tap it on a table or a surface to make sure there are no air bubbles in the plaster
Pour more of the plaster mixture into the mould until it is almost full
Being a swift as possible, place the core with the pointy part of the triangle downwards into the wet plaster
Tape the top of the core to the sides of the mould so that it doesn't float up.
Place the mould in a cool dry place and leave it to dry for 2 to 3 days

STEP 10: Step 10: Removing the Product Out of the Mould

Once you have let your plaster fully dry, use an exacto knife to cut the taped edges of the mould.
Peel the HIP off the plaster which should now reveal the final product.
Now to remove the core, use the exacto knife to cut the edges of the top of the pyramid (triangle).
Use the loose face to pull the core out of the plaster.
Be as gentle as possible to avoid crushing the final product.

Take pictures of it and enjoy your final paper weight!