Introduction: Casting Plaster-plant Pot

instructables for Casting plaster unit

also , technically you could use this as a plant pot OR as a pencil holder


~pencil (any but recommend HB so you could erase it easier if made a mistake)

~ 3 piece of A4 paper (might need 4 or five, depends on how you draw it, i used 3)


~set square isometric/the 45 one


~3 piece of A4 sized high impact polystyrene (or more)







Step 1: Choose One

you could draw shapes right on the high impact polystyrene OR

you could draw it on a paper first, cut it , paste on the polystyrene by using glue stick THEN cut out the polystyrene.

recommend the second choice, but if you're lazy, why not do the first?

Step 2: Starts Drawing-mould

shapes needed for the mould

~5 equilateral triangles (6 CM)

~5 diamonds

~5 weird shape (i have no idea what you call this)

~2 pentagon, one 3.6cm, one 6cm draw the equilateral triangle you place the set square at the side and draw a line of 6 cm the protractor on one end of the line (see picture 1)

3.draw a tiny line at the end of the 60 degrees(use the 60 degrees that's going inwards)

4.repeat with the other end of line. set square(see picture 2)

6.draw line 6 cm (both side)

7.draw another 4

for diamonds, you draw the triangles together like this (see picture 3)

repeat another 4 times

for the weird shape,

1.draw another 5 triangles, all the triangles must be like this (see picture 4 ) , the side face upwards so you could the quadrilateral

2. place the set square on the top line ,measure 3 cm and draw a tiny line it upside down (90 degrees) the line that's already drawn must be placed at 1.8 , then draw a line of 3.6 (photo 5)

4.repeat 4 times

for the pentagon

1.draw a line, 6 cm, measure 108 angle draw a tiny line set square, connect , draw line 6 cm

3.repeat with the other sides,

4. do another pentagon with 3.6 cm

Step 3: Cut the Shapes-mould

if you're doing this on paper, i recommend to not cut on the lines, but cut outside the lines so when you cut it on the polystyrene it will make your lines more accurate

cut the shapes for the diamond and the weird shape, do not cut the lines that connects the shapes together, but if you made a mistake, it's fine just glue them on in the same way, if your using high impact polystyrene, then too bad

if you did it on paper, use glue stick and paste them on the polystyrene

then cut them

Step 4: Make Mould

at this point you should have 5 diamonds, 5 triangles, five weird shape and two pentagon that's different sized.

1.use tape to connect them, (see photo)

2.take the side with the tape

3.fold it a bit to loosen up

4.connect the sides that's next to each other, use tape

if it looks like it's not gonna connect, it's FINE , just forcefully connect them bc that's what i did :D

5.cut out the pentagon that's bigger, so now it should look like that (picture) but without the top pentagon

6. MAKE SURE IT DOES NOT LEAK, use lots of tape , to check if it leaks or not, put water in , if it's a few drops, it's still fine

Step 5: Core

do the same steps as the mould but change the measurement , the equilateral triangles is 5 cm per side, the two pentagon is 5 cm and 3 cm and for the weird shape it's 5 cm on one side , and 3 cm on the other with 3 cm as their height

Step 6: Mixing Plaster

1.first place the mould on a table with the core next to it

2.grab the bucket and the spatula

3. put in 2 cups of water, the cup can be found at the design lab , it's the meiji/dutch milk (can't remember) yogurt cups

4. put in 3 cup of plaster

5.slowly mix it, (wear mask, put on apron and tie your hair if it's long)

6. when it's a solution then pour it in the mould

7.gently push the core in, same position, be very careful to make sure it's the same direction

8. the top of the core must be the same level as the top of the mould

9. press the core for like a while, you can stop when the core don't float up

Step 7: Last Step

1.wait at least 14 hours, the longer the better

2.when done, gently peel off the mould first, cut the tapes out with the cutter to separate the shapes

3.cut the core out, this one needs to be more careful because the walls of this pot/vase might be too thin

when you're done it should look something like that , but the top part should be even , i used the cutter to cut mine's to shape the side into curves

if you succeed, CONGRATS! you done it !! whoop 🥳🥳🥳

if you don't....... it's fine, it probably is my fault, i'm sorry