Ceramic Workshop-Making a Plaster Mould

1) Firstly you need to put an apron on, and make sure your work space is clean. Then you need to find an object you can cast, I chose to cast a plastic duck. A plus to the plastic duck was it already had a mapped out circumference around the object.

2) You take a plaster board and place the rubber duck in the centre of the board, using clay you emerge the duck and surround it by building the clay around, making sure you square up the sides.


3) Once the clay is even and roughly in a cube shape, place boards around and secure them there by sealing the sides with clay to stop the plaster from leaking through.


4) Now to mix the plaster, when weighing out plaster make sure you wear your mask and put the dust extractor on. I need two pints which was 1.5kg of plaster powder. 1 pint would be 750g of plaster powder. You take a clean bucket and add the two pints of water first then sprinkle in your powder, leave to soak in a bit for 2 minutes.

5) After 2 minutes gently stir using your hand to remove lumps and gently agitate the mixture to get rid of any air bubbles, once the bubbles float to the top just scoop them out. Once you can feel the mixture thicken and you can draw a figure eight on the surface and be able to see it, the plaster is ready to pour in to your mould.

6) Once you have poured your plaster in your mould make sure there’s no leaking and leave to set for 20 minutes.


7) After the 20 minutes is up the plaster should have set. So remove the clay from the boards then remove the boards. You then remove the clay half of the mould but being careful to leave the plastic duck in the plaster mould intact.

8) You then need to clean up the plaster mould, using a damp sponge wipe any remaining clay off the surface and the duck. Then using a grater clean up sides and edges removing any rough uneven edges.

9) You now need to make notches to help lock the mould together. Take a penny and twist into the plaster gouging out a circular indent , do this on either side of the mould. Now take soft soap and a sponge and rub it on to the plaster, then wash out the sponge in clean water and wash it off do this three times. On the third wash do not remove the soft soap, make sure its coated but not fully layered.

10) Board up the sides again and add clay to stop leakage. Mix another 2 pints of plaster and repeat the plaster making process (step 4 and 5). Then pour the plaster over the plaster mould. leave set again for 20 minutes.


11) Remove the boards and gently pull apart your mould, clean the edges again and make sure you write your name and course on the mould then place it in the plaster drying cabinet for about 2-3 days. Then your mould is ready to use and slip cast. Bellow is my outcomes.




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