Ceramics - Final Exam

Why has the glaze crawled?

• application too thick/dust on pot before glazing

• should always dust off pot with damp sponge before glazing

Can I use many glazes on one pot?

no—glaze will run to the bottom and the pot will stick to kiln shelf

How long should I hold my pot in a bucket of glaze so I know it is good coverage?

• 3 seconds

• coloring oxides and water

• impart only color to a surface under a glaze or over (to give a more controlled area of color)

• may be used on greenware or bisque-ware

• highly concentrated so use sparingly

oxide wash

What are some glazing decorative techniques?

• wax resist

• coloring oxides

• brush work

• underglaze colors

• sponging

What causes a piece to come out dry and rough to the touch?

the glaze was applied too thinly, barely covers the surface

Should you wait for glaze to dry completely to apply another coat?

no, do when slightly damp

Why is glaze cracking off piece?

too thick/too many layers of glaze

Why is wax resist on the bottom of pots important?

prevents glaze from running onto the kiln

Why isn’t glaze drying on pot after washing off unwanted application?

too much water, wait a few days to reglaze

What is the most unique and workable quality of clay?

plasticity

What are 3 types of clay bodies?

porcelain, terracotta, stoneware

What is fine china primarily made up of finely-ground cow bone?

bone china

Why do we wedge?

to get rid of air pockets

A clay object, not yet fired

greenware

Why do we put “fillers” in clay?

strength, “tooth”

3 properties that make clay different from sand or dirt

1. plasticity (most important)

2. porosity

3. vitrification

process of joining two pieces of clay together (while leather hard)

score and slip

What is the chemical formula for clay?

(Al2O3)•(2SiO2)•(2H2O)

• quartz

• important for closs

• mixed with alumina to stop the “flow” so it doesn’t puddle

• causes vitrification

silica

Why can’t bone dry and wet clay be attached?

it will crack

all products made from clay

ceramics

what are 3 techniques used to decorate clay?

scraffito, brushwork, carving, stamping

A receptical used to hold clay pieces and fire them

Kiln

used to coat kiln shelves to prevent glaze and clay from sticking during firing

kiln wash

What is the first firing called?

bisque

What is the difference between hand building clay and wheel throwing clay?

hand building clay has looser platelets, a lot more water in between; wheel throwing has tighter platelets

Why is it important to glaze inside of piece?

Expand and contraction 

• defects in pottery

• can result from improper mixing, application, or firing processes.

glaze faults

What are examples of glaze faults?

crawling, pinholing, blistering, crazing, and shivering

kiln firing technique where the amount of oxygen is reduced

reduction firing

kiln atmosphere is oxygen-rich

oxidation firing

cone placed in the kiln to monitor the firing process and help determine when the desired temperature has been reached

guide cone

to gauge the temperature reached inside the kiln, once this one bends the correct temp has been reached

target cone

• placed alongside the target cones during a kiln firing.

• serve as an additional indicator of the firing process

• provides a backup measure for monitoring the temperature inside the kiln

guard cone

What are cones made up of?

ceramic/glaze material

How to prevent s-cracks?

compressing the bottom

What color does a cobalt oxide create?

blue

What is the most important part of wheelthrowing?

Centering