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06/11/2019 PROJECT DATE 04/12/2019 PROJECT DATE 04/12/2019 PROJECT DATE 06/11/2019 PROJECT DATE 04/12/2019 PROJECT DATE

1. MATERIAL BASICS

NAMES
CERAMICS ESSENTIALS

LOCATION
ONLINE AND IN THE CASTING LAB

DATE
TBC

DURATION ONLINE
20 min

DURATION PRACTICAL
60 min

MANDATORY REQUIREMENTS
BE REGISTERED ON OUR WEBSITE

LEARNING OUTCOMES
AN UNDERSTANDING OF MOULD MAKING

MIXING AND CASTING CONRETE

CHALLENGE
MAKE AND CAST A TILE

 

HAZARDS
CORROSIVE MATERIALS

REMEMBER
ALWAYS WEAR THE CORRECT PPE

Ceramics Essentials will teach you the fundamentals of using the Casting Lab. The Essentials is divided into two parts, an online part and a practical.
The course starts below by taking you through some basic steps you need to learn to start using the Lab. It will also introduce you to the most common materials used: plaster and clay, their properties, the Hazards and Controls of each material, and how to use them. Once you have read all the information you will need to complete a short quiz. The following step will take you through what you need to know to complete the practical part. Then you will be ready to book your practical.

5 THINGS TO KNOW ABOUT THE CASTING LAB

1. PREPARE IN ADVANCE

Do your research, buy your materials, build your moulds. The better prepared you are the more successful you will be.

2. LEAVE YOUR STUDENT CARD AT THE LABSHOP AND BORROW YOUR EQUIPMENT

The Casting Lab is an unsupervised space and only 5 people can use it at one time. All the equipment you will need must be loaned from the shop. There are 4 kits to choose from depending on what you want to do.

  1. Plaster Casting Kit
  2. Modelling with Clay
  3. Concrete Casting Kit
  4. Material Extrusion Kit

You will only need Plaster and Clay for the Essentials.

3. ONLY MATERIALS THAT HAVE HAD A COSHH ASSESSMENT CAN BE USED.

COSHH (Containment of Substances Hazardous to Health) is an assessement of the risks involved in a material. This is a legal requirement. All materials need one, and the hazards involved are removed or reduced by our control measures. All materials bought in the shop have had a COSHH assessement. If you bring a material from outside please speak to a member of staff beforehand. 

4. USE A BENCH INSERT

Every bench has space for two bench inserts. If you are casting liquid materials (plaster or concrete) you will need a plastic tray. This will capture any spillage and leaks. If you are working with clay or similar materials you will just need a wooden board to create a flat surface to work on. For the Essentials you will need one of each.

5. CLEAN UP AFTERWARDS

Pour waste material into the bucket in the sink, if poured directly down the drain it will block the drain. Wash all equipment, and return it to the Lab Shop. Do not leave anything to dry on the side. Wipe down the benches with a sponge.

5 THINGS TO KNOW ABOUT PLASTER

1.PLASTER IS A MINERAL CALLED GYPSUM THAT WHEN HEATED BECOMES A FINE WHITE POWDER CALLED CALCIUM SULPHATE (PLASTER OF PARIS)

2. WHEN MIXED WITH WATER IT DESOLVES TO BECOMES A LIQUID. THERE IS AN EXACT PROPORTION OF PLASTER TO WATER.

Too much plaster powder will make the mixture too thick and unable to cast. Too little plaster will leave the plaster wet and soft forever.

3. PLASTER CURES IT DOES NOT DRY.

The water added to the plaster does not evoprate it is absorbed by the Calcium Sulphate Hemihydrate (the mineral name of plaster of Paris) forming a series of interlocked crystals that form to make a solid. 

4. PLASTER CAN STICK TO YOUR MOULD.

Like cake making, the mould for casting needs grease. This grease is called the release agent. In baking you might use butter, when using plaster we use petroleum jelly.

5. PLASTER CAN BE HAZARDOUS

As the plaster cures it creates heat as part of the reaction. The heat generated is safe under most conditions unless you have decided to cast your hands in a bucket of plaster. DO NOT DO THIS. Your hands will cook in the bucket and you will lose your fingers.

DO NOT CAST YOUR BODY PARTS IN PLASTER.

5 THINGS TO KNOW ABOUT CLAY

1. CLAY IS A FINE GRAINED SOIL DUG FROM THE GROUND.

2. CLAY CAN ONLY BE USED WHEN WET.

Clay has a putty like consistnacy, it can be rolled into 'slabs' and cut with a knife. It can be carved, pressed and sculpted with modelling tools. It can be rolled into long 'sausages' and 'coiled' to create forms. It can be 'thrown' on a potters wheel. However it must always be kept damp. To continue working on a project wrap it in plastic to stop it drying out.

3. CLAY IS CONVERTED INTO A CERAMIC WHEN HEATED.

Clay is left to dry on the shelf and is then fired in a kiln to 900C. This process is called bisque firing. When glazed it is re-fired to 1200C.

4. CLAY CAN CRACK OR EVEN EXPLODE IN THE KILN.

Large volumes of clay can explode due to thermal shock or the presence of trapped air bubbles. A brick, for example, is very hard thing to fire correctly.

5. CLAY CAN BE HAZARDOUS

The dust from dry clay can be hazardous to your lungs so only use clay when wet and tidy up benches by wiping with a damp sponge. Never sand or scrape dry clay.

 

5 THINGS TO KNOW ABOUT MAKING A MOULD

1. IT IS THE NEGATIVE OF WHAT YOU WANT TO CAST.

Think of it as the inverse, or the opposite of what you want. For example if you want a wall you mould a trench.

2. YOU MUST BE ABLE TO MANAGE THE SIZE OF THE MOULD

It is easy to under estimate how much plaster will be needed. Start by drawing it out and working out the volume. To give you a guide a 10cm cube (this is small) uses 1 litre of liquid plaster, this is about 800g of powdered plaster and 615g water (this is quite a lot). Anything larger than the plastic tray bench insert will need staff assistance.

3. IT MUST BE WATER TIGHT

You are pouring a liquid in, you do not want that liquid to leak out. All gaps and holes must be filled. Waste bits of clay are very good for doing this. 

4. USE AN APPROPRIATE MATERIAL FOR YOUR MOULD AND A RELEASE AGENT IF NEEDED

As a general rule the more porus and absorbant the material, the less suitable it is for making a mould. Card is both weak and absorbant so oftenn it is a poor choice. Some materials need sealing first such as MDF and Plywood (you can use thinned down PVA glue). Plastics are very good becuase they are water resistant, but they are rigid. Silicones and alginates make great moulds because nothing sticks to them and they are flixible. But they can be expensive. RESEARCH, DESIGN THOUGHTFULLY AND CHOOSE WISELY.

5. YOU WILL NEED TO GET YOUR CAST OBJECT OUT OF THE MOULD.

The liquid you pour in will convert into a solid. Any 'undercuts' will inhibit the demoulding of your casting.

 

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