Ceramic Workshop: Plaster Mould Making (part I)

I was in the ceramics workshop today learning the technique of making plaster moulds. My plan was to use this technique to make small samples to lay the foundations for a possible future foray into bioplastic moulds.

Plaster moulds are an ideal tool for experimenting with new design ideas as they are not only inexpensive, but also allow for precise replication of detail, which is crucial to my design practice.

Material
- Plaster powder 100g
- Water 70ml

Production steps
1. Mould fixing: Use clay to fix the mould, using the parting line of the product as the dividing area. This step ensures the stability of the mould during the production process.

2. Leakage prevention measures: Fix the position of the mould with a wooden board and subsequently fill the gaps with clay. This is a critical step to prevent the plaster solution from spilling out from the edges.

3. Plaster solution preparation: Mix 100g of plaster powder with 70ml of water in proportion. It is important to pour into the bucket in batches and mix by hand in the same direction to ensure an even mix.

4. De-bubbling: Shake by hand in the solution to help the bubbles at the bottom to rise and squeeze out. Subsequently skim off the surface bubble floats by hand.

5. Stirring and checking: Continue stirring for about 2 minutes and check that the plaster solution has been homogenised by making a cross on the surface. The appearance of a scratch indicates that the plaster solution is ready.

6. Pouring into moulds: Pour the solution into the moulds quickly, this step requires quick action to avoid the plaster starting to solidify.

7. Shake the mould: after pouring, shake the mould to ensure that any air bubbles inside are completely squeezed out, this helps to ensure that there are no voids inside the moulded plaster.

Reflection and Questions
1,How can I improve the quality of my gypsum solution?
There is a risk of air bubbles and uneven mixing when mixing gypsum powder and water. I need to explore more effective mixing and degassing techniques to optimise this process.

2,Control of accuracy:
Accuracy and promptness are crucial in the process of pouring gypsum solution into the mould. What should I do to improve the accuracy of the operation to ensure optimum results with every pour?

3,Mould integrity:
While filling gaps with clay is effective, is there a more efficient or professional way to ensure that plaster does not spill over the edges of the mould?

Plaster mould making in a ceramics studio is a detailed and highly technical process. Each step requires precision and a deep understanding of material behaviour. Through this production, I not only learned specific techniques about plaster mould making, but also improved my skills and patience in handling delicate work. These experiences will provide me with valuable technical support in my future ceramic making and other precision processes.