The reason why Jianshui purple pottery is widely polished is that a layer of oxide is formed on the surface after firing, and the color is mostly gray, which covers the true color of purple pottery. After the oxide layer (commonly known as fire skin) is polished off, the true appearance of purple pottery can be revealed.
At present, the operation process of grinding is mostly: first, remove the fire skin on the surface with sandblasting machine, but it still appears rough, and then polish it with the help of fiber wheel. To polish the light, we need to use the turntable of the billet drawing machine. The wet towel is pasted with emery to fix the work on the turntable. With the rotation of the turntable, both hands hold the wet towel to contact the surface of the purple pottery work, and constantly Polish until it is bright. Although with the help of some external forces, grinding is still a very laborious work.
The result of standardized grinding is that the surface of purple pottery is similar, and it loses its individuality. In fact, in the past there was no sand blasting machine, emery era, grinding is using sand and stone, all rely on manpower bit by bit. Although it can not achieve the modern smooth jade, or even the effect of light, but rely on sand and stone hand grinding out of purple pottery, each piece has its own personality, and Jianshui purple pottery’s texture of gold and stone is reflected incisively and vividly.
In fact, fire skin is also a part of purple pottery art to a large extent. After being put into the kiln, the purple pottery will form some special fire skin under the difference of flame, fire situation and kiln atmosphere. However, under the standardized grinding process, all these beautiful fire skins will be polished off, which is a pity.
Picking up the traditional manual grinding again, although it is very laborious and time-consuming, the polished works are not only full of personality, but also can selectively polish and retain a part of the fire skin according to the firing effect and decoration layout, which can play the finishing point.