Ceramics 101
This class covers some basic handbuilding techniques to work with clay.
Equipment & Materials Needed
Equipment
Rolling Pin
Wire Cutter
Pin Tool
Loop / Ribbon Tools
Wooden Modeling Tools
Acrylic Templates
Bucket for water
Pieces of canvas (to roll clay between)
Paintbrush
Materials (per student)
Clay (.5 kg)
Underglaze
Wax Resist
Clear Glaze
Safety Considerations
Recommended:
Remove dangling jewelry
Tie back long hair
General Rules
Welcome to the ceramics lab! We have a few rules to keep this space tidy, and minimize breakage of people’s projects.
No outside clay. Clay must be purchased from MakerLabs. This will ensure that we know what is going in the kiln. Different clays can fire at different temperatures, and if the settings are used for the wrong type of clay, work can cause damage to the kiln, or explode and damage other’s projects.
Always clean up after yourself. All tools should be cleaned and put away, and tables should be wiped down after each use.
Do not use the utility sink that is hooked up to plumbing. We want to prevent clay from going down the drain and clogging up our pipes. Use the sink that is located in the ceramics lab when needed. Make sure there is a bucket under it to drain into.
No sanding. Sanding creates silica dust that is very bad for your lungs. We do not want it floating through the space, so no sanding is allowed in the ceramics lab. If it’s absolutely necessary that you sand your work, you must do so in the sanding booth in the WoodLab, with proper dust collection.
Those using the studio outside of class times, must store their work and any items they wish to store in the studio in their designated storage shelf.
MakerLabs is not responsible for any projects or materials that are left in the Ceramics Lab or any damage that occurs upon firing work. It is your responsibility to make sure that your clay is properly covered when needed, and pieces are made properly to prevent damage to your own and other student’s work when firing.
Initial and date your work. Once projects are fired, they will be returned to members’ storage shelves. Those participating in classes will be notified once their projects are ready for pick-up. We aim to have projects ready within a month of taking the class. Students must pick-up their projects within two weeks of notification. Failure to do so may result in disposal of your project.
Fees
Bag of Clay: $50/10kg bag. This includes the use of underglazes, glaze, and firing. There is no limit to how much clay you can purchase in a month.
Ceramics Lab Drop-In Rate: $30/day
Different Stages of Clay
Wet Clay
This is the form that clay comes in when first purchased. Wet clay must be wrapped in plastic to keep it in a usable state, and prevent it from drying out. It typically comes in 10kg bags, and can be cut in pieces as needed to produce many different pieces. Both handbuilt and thrown pieces start out using wet clay. Clay contains about 20% moisture, and will shrink one dry / fired.
Slip
Slip is clay that has had water added to it to make it into a liquid or paste. Slip is most commonly used when joining two pieces of clay together (ie. a handle to a mug body). It can also be made extra runny and used for “slip casting” where slip is poured into a mould, which is then fired, to cast pieces of pottery.
Leather Hard
When wet clay has dried slightly, but is not fully dry, it is called “leather-hard”. At this stage, you can trim and carve decorative elements into your work. Leather hard is also the state where you would use underglaze.
Dry (aka Greenware)
When clay is fully dry it is also known as Greenware. It is most fragile at this state, and needs to be handled carefully to prevent breakage. Once clay has reached this state, it is ready to be bisque fired.
Bisque
Bisque is clay that has been fired once. This changes the chemical and physical properties of the clay. Clay is still hard, but porous enough that it will absorb glaze. At this stage, glaze is applied for the final firing. Projects can be dipped in glaze, or have work poured in / over it. Water is absorbed into the clay, making the glaze stick to the surface of the pot.
Glaze Ware
After a second firing at a higher temperature, the clay and glaze have fused together to make a finished product that has a non-pourous surface. At this point, your project is ready to use.
Different Types of Clay
Earthenware Clay
Earthenware clays are low fire clays. The temperatures at which low fire clay is fired at ranges from between 1479 and 2109F (804-1154C). A lot of earthenware clay is red or orange, because it has a high content of iron oxide.
Stoneware Clay
Stoneware clay fires at higher temperatures than earthenware clay, and it is tougher than earthenware clay once fired.Compared to earthenware clay it is denser, more resistant to breaks and chips, and less porous. Stoneware clay comes in different colors, but it’s often grey when it is moist. The depth of color will vary from a pale grey to quite a deep grey color. It is often used to make dinnerware.
Porcelain Clay
Porcelain is a high fire type of clay, which means that it usually fires at temperatures from 2232F (1222C) upwards. Once fired, porcelain is normally white and can have a translucent appearance. It can be shaped into thin, delicate forms, and is very dense and hard.
Hand Tools
Rolling Pin
Used for rolling out clay when handbuilding. Clay can be placed between two pieces of canvas, to avoid having it stick to the rolling pin, and to create an even surface.
Wire Cutter
Used for cutting off large pieces of clay from a block of clay. Is also used to remove work from a potter’s wheel.
Metal & Wooden ribs
Metal - to smooth and compress clay. Makes the clay easier to work with and less likely to crack
Wooden - used primarily for wheel work. Helps to shape objects that you’re throwing.
Pin Tool
This can be used to trim the edges of pieces (especially when using a wheel), or for scoring clay with attaching pieces (ie. handles, coils, etc.). When attaching clay, we would always score the surface, add slip, and then attach the piece to make sure it doesn’t fall off when it dries.
Loop / Ribbon Tools
Use for trimming / carving into work, and are especially good for hollowing out thick areas. Also used in wheel work to trim feet on the bottom of pieces.
Wooden Modeling Tools
For smoothing and shaping clay. Can work as extensions of our fingers to do what our hands can’t. Can be used to add texture or sculptural techniques to the clay.
Sponge & Shammy
Used for smoothing out the clay, or absorbing any excess moisture.
Banding wheel
Used to rotate work while glazing or building.
Cookie Cutters
Can be used to cut consistent shapes.
Building a Mug
There are three main hand building techniques.
Pinch
Pinching clay between thumb and finger to make objects.
Coil
Rolling long strips of clay with your hands, coiling the objects around themselves to start building upwards.
Slab
Using a rolling pin and rolling out flat pieces of clay and constructing objects with them. You can make a variety of different boxes and shapes that use flat pieces. You can also use a slab roller, which is a tool that will roll the clay into slabs of a desired thickness.
In this class, we’re going to focus on slab hand building.
Preparing the Clay
When starting with clay, we need to work it before we can begin building with it.
With your piece of clay, throw it down on the table a few times, to get it into an even / square shape.
Next we start “wedging” the clay. Wedging clay is like kneading dough, where we try and remove any air bubbles in it. If air bubbles are left in the clay, it could cause our piece to crack, or to explode when being fired in the kiln.
There are two ways to wedge clay, the spiral method, and the “ram’s head” method.
Spiral Method
Move the clay in quarter turns, so it will be harder on one edge, and curved on one edge, almost shaped like a flower.
Ram’s Head Method
Gripping on either side of the top of the clay, use the heel of our palms to push on the base of the clay repeatedly, to eventually form a shape that will be similar to a ram’s head.
Once the clay is wedged, it’s ready to be worked into shapes.
Handbuilding with clay
Place your clay on top of one piece of canvas, and roll out the clay using a rolling pin, trying to get it as even as possible. Roll the clay until it reaches about ¼” in thickness.
Using the templates, place them on top of the clay, and use the pin tool to cut out the shapes.
Cut a 45 degree angle to one edge of the clay, and an opposite 45 degree angle to the opposite edge of the clay.
We’re going to wrap the sides of the mug, around the base of the mug, and attach them together. When we attach two pieces of clay together, we need to do something called welding. If we try to attach two pieces of clay together without welding, as the clay shrinks it pulls away from itself, the pieces will fall apart. In order to avoid this, we need to score, slip, and smear the clay to make sure the pieces attach properly and stay together.
Using the pin tool, score both pieces of clay with hatch marks in the areas where you will be attaching them together to make it rough. This can be where the sides of the mug overlap with each other.
Add slip on top of the score marks, making sure that the slip doesn’t make the clay too smooth. If it gets too smooth, rough it up again with the pin too. The slip will act like a glue, and will help hold the pieces of clay together.
Stick the pieces of clay together at the points where the hatch marks are
Smear the pieces of clay together along their seams.
With your mug body, place it on top of your remaining clay, and use it as a guide to cut out the base of the mug.
Score, slip, and smear the base of the mug to the body.
If it’s difficult to smear the seams together, make a thin coil of clay, place it in the seam, and use it to smear the seams together.
A modeling tool can also be used to smear the seams together, by using the tool to pull the clay downwards or upwards.
Follow the same process to attach a handle to the mug, scoring both ends of the handle, and scoring the area where the handle will attach to the side of the mug, adding slip, and smearing the clay.
If you choose to make any decorative elements out of clay and add them to your piece, attach them using the same method of scoring, adding slip, and smearing the clay.
Once you’re happy with your mug and have it complete, write your initials and the class date on the bottom of the mug using the pin tool.
Cover your project up with a plastic bag and put on the shelf for next week. This will make sure the clay doesn’t dry out too fast, which would cause it to crack. It should be at leather hard stage by the following week.
Any left over clay can be recycled into other projects.
Leather Hard
Once the pieces have dried a bit, they will be at the leather hard stage. At this stage, the bases of the mugs can be trimmed, and any additional decorations can be carved into them. This can be done with the various hand tools. Once happy with them, it’s time to add glaze.
Using Wax Resist
To make sure the clay doesn’t stick to the kiln, all pieces must have wax applied to their bases. The wax will burn off in the kiln once fired.
The wax will be applied with a brush. To help preserve the bristles, dip the brush into cold, soapy water before using the wax resist.
Apply the wax to the entire bottom of the mug, and ¼” up the sides. Make sure your brush isn’t loaded with wax, as any excess can drip down the mug, and is difficult to clean off. Be careful not to get the wax anywhere you don’t want on your mug, as the glaze will not stick.
You can use wax to also make decorative designs. Wax can be applied to the entire mug, carved into, and glaze applied to the negative space. Any excess glaze can be cleaned off with a sponge.
After applying wax, wait 5 at least minutes for it to dry, before applying the underglaze.
All wax brushes should be kept separate from glaze brushes. To clean the wax brushes, use a small container, pour boiling water on the brushes, and mix them around in the container to clean off the wax. Remove the brushes once they’re clean. Wait for the water to cool, the wax will solidify once cooled, and can be disposed of. Do not pour wax down the drain.
Working with Underglaze
Underglaze is applied to work that is leather hard, using a brush. Make sure to stir the underglaze before applying it. At least two coats should be used when applying underglaze. There are a few different techniques that can be used when applying Underglaze.
Scraffito
After applying underglaze, wait until the glaze is dry enough so it is firm to the touch. Using the pin tool, or modeling tools, carve into the clay, to reveal the natural colour below. Make sure to remove any excess clay from your tool when carving.
Layered Scraffito
This technique is done by using multiple colours of underglaze, painted on top of each other. When applying each layer of underglaze, wait a few minutes for the underglaze to dry before applying the next colour. Once it’s dry, use a carving tool to carve away the clay and reveal the layered colours.
Inlay
Carve into your clay, making sure there aren’t any raised edges. Using a brush, fill the carving with underglaze. Once it’s dry, gently wipe away any excess glaze.
Painting
Using the underglaze, you can paint the mugs the same way you would use regular paint. Make sure not to contaminate the glaze containers with other colours. The glaze can be applied using a paintbrush. If you choose to mix your own colours, use a palette. Just note that because glazes are made using different minerals, traditional colour theory may not apply, and mixing colours together might not give you the desired result. (ie. Red and yellow together might not make orange)
After applying the underglaze, the mug will need to finish drying. Once it is dry, it will be ready to bisque fire.
Cleaning Up Underglaze
After glazing, brushes can be cleaned with soap and water. Place soap in your hand, and swish the brush around in your hand. You will need to repeat this process a couple of times until the brush is clean. It will be clean once the brush doesn’t change the colour of the soap. Make sure to rinse any soap off of the brush.
Applying Clear Glaze
After bisque firing has been completed, a clear glaze will need to be applied to the mug, prior to the final firing. Wax the bottom, and using a brush, apply the clear glaze.
Once the glaze is dry, the mug will go through it’s final firing, and students will be notified once the mug is ready to pick-up. We aim to have all work ready for pick-up within a month.
Clean Up
All tools must be cleaned and surfaces wiped down every time you’re finished working in the Ceramics lab.
Tools must be cleaned in the Ceramics Lab sink, making sure there is a bucket of water set-up under the sink to drain into.
Work tables should be scrubbed with a wet towel, making sure any bits of clay are removed. Any clay that dries and hardens can get into other people’s work and could cause it to crack / explode when fired
Reusing clay
Extra leftover bits of clay can be recycled and used for future projects. However, clay doesn’t like to go back together easily if it’s at different levels of dryness. If you have leftover clay, try and form it into a big blog, and slam it into a solid shape. Poke some holes in it, spray with water, cover in plastic, and let it sit overnight, making sure the plastic is sealed. After it has sat overnight, wedge the clay to prepare it for use.
Resources:
Decorative Glazing:
https://www.youtube.com/watch?v=03I49swV6EA
https://www.youtube.com/watch?v=ctYc1nJ5pr4&t=409s
History of Ceramics:
https://deneenpottery.com/pottery/
https://moa.ubc.ca/koerner-european-ceramic-gallery/
How cars are designed using clay models:
https://www.youtube.com/watch?v=H7dRVWX8ywM