What is the difference between casting and carving in sculpture?
Carving is a subtractive process whereby material is systematically eliminated from the outside in. Casting: Sculptures that are cast are made from a material that is melted down—usually a metal—that is then poured into a mold. Casting is an additive process.
What technique is used to make cast sculptures?
Lost-wax casting
What material is used in sculpture?
The metal most used for sculpture is bronze, which is basically an alloy of copper and tin; but gold, silver, aluminum, copper, brass, lead, and iron have also been widely used.
What type of clay should I use?
Porcelain and kaolin clays are virtually identical and are considered the best clays available for making pottery. They are also the most expensive. They are a largely silicate clay and are resistant to high temperatures. If you want to make high-quality ware, then this type of clay is best for you.
What does grog do in clay?
Grog is used in pottery and sculpture to add a gritty, rustic texture called “tooth”; it reduces shrinkage and aids even drying. This prevents defects such as cracking, crows feet patterning, and lamination. The coarse particles open the green clay body to allow gases to escape.
How much grog do I add to clay?
A sculpture clay body, for example, typically has 15-25% grog (but can have much more). Since grog is typically prefired, its does not normally undergo a firing shrinkage (unless the body in which it is a part is fired to a temperature higher than the grog was initially fired at).
Can you fire leather hard clay?
As water will leave the clay during the firing process, you need to make sure the clay is as dry as possible before you put the glaze on. Some potters recommend leaving the clay to dry to a bone dry level before glazing, as leather hard pieces still carry quite a high level of water content.
How do you calculate clay shrinkage?
Math to find shrinkage; (Dry measurement – fired measurement) divided by Dry measurement X 100 = % shrinkage. EX; 1 (dry) – . 875(fired) divided by 1(dry) X 100 = 12.5% I converted the fraction to decimals (7 divided by 8 = . 875) to make it easier.
What is a shrinkage factor?
1. A percentage in short fall of a planned output amount. 2. a percent of inventory lost due to errors, theft and spoilage or waste.
How do you keep Clay from shrinking?
The simple answer is: Don’t allow any moisture to evaporate from the clay. If the clay remains wet, it will not shrink or crack. I have seen sculptors encase wet clay in glass jars, resin blocks, and even polyurethane.
What happens when clay shrinks too quickly?
Atmospheric Drying As the clay is slowly heated, this water evaporates out of the clay. If the clay is heated too quickly, the water will turn to steam right inside the clay body, expanding with an explosive effect on the pot. This will result in the clay compacting and some minimal shrinkage.