Shadow Weaver

Chapter 136 Zisha Pottery Making Experience Class.jpg
The mineral materials just mined from the mines have complex composition and must first be manually selected to carefully pick out the suitable purple clay ore.

Most of the newly selected mineral materials still contain a certain amount of moisture and cannot be crushed and screened immediately. They need to be piled up in the open air to dry and weather for a period of time.

Only weathered minerals can be crushed with stone mills for subsequent screening and mud refining.

"Wow - so stone mills are used to crush purple sand ore? I thought that by now, electric mills must be used!" Seeing Gong Zhou pushing a small bag of weathered ore into the hole of the stone mill, Bai Miaomiao exclaimed softly with bright eyes, and there was a group of unrestrained interest in her pupils, "Teacher Gong, don't you think the efficiency of the stone mill is too low when you crush the ore?"

"When doing this kind of heavy work... electric grinders are faster, right?"

"My arms are about to break in pain just thinking about how much weathered mineral material needs to be ground into pieces with a millstone."

"Oh, it is true that the electric grinder is faster in crushing." Gong Zhou nodded, "But the material produced by the electric grinder is not particularly uniform, and the particles are not particularly regular."

"The mud particles ground by stone mill are more uniform and breathable... Let me think about how I can give you an example."

"Comrade Xiaobai, have you ever used an electric meat grinder at home?" Gong Zhou scratched his head. "When you use that thing, if you don't add a little water to it, or if you don't put in the right amount of ingredients, it's easy to grind the stuffing into a fine bottom and a coarse top... or there will be some that are not ground at all."

"But if you use an old-fashioned manual meat grinder or chop it with a knife, this problem will basically not occur - the old-fashioned machine will at most make the meat a little coarser, and chopping it with a knife will be very laborious."

"Hmm... when I think about it, that's true." Bai Miaomiao poked her head in thought for a moment, then nodded in agreement - although she couldn't cook, when she was still at home, she did hear her mother complain that the newly bought meat grinder was not easy to use and was not as convenient as the old one.

——Although it is fast, it can only twist a certain point at a time. If you use more than one knife, it won’t be able to turn.

"But even so, Mr. Gong Zhou, it's too much trouble to pull the stone mill by hand, right?" The girl in Hanfu frowned and said in amazement, "Especially for a studio as large as yours... If all the ore materials have to be crushed manually, how much time do you have to pull the stone mill in a year... Can you pull it?"

"Haha, if it's purely manual, then of course it can't be pulled." Gong Zhou grinned, his tone still calm, "So now we usually use electric motors to pull the mill - although we can't use electric mills when we crush ore, we can change the pull mill to electric!"

"Eh? That seems to make sense." Xu Yichi, who had been watching them fiddling with the stone mill for a long time, tilted his head and pointed to the small stone mill on the table, muttering, "So this mill is just for demonstration in our class?"

"Yes, Xiao Xu, look at this room, it's decorated so normally... There's no way this is used to crush purple sand ore!" Gong Zhou laughed, "We have a special site for weathering and screening minerals... What can be brought here are just samples for teaching students."

"Come on, Xiaobai, try pushing the millstone twice."

"Okay!" Bai Miaomiao responded straightforwardly. In fact, she had been eager to try the stone mill under Gong Zhou's hand for a long time, but she was more reserved because she thought that there were quite a few students in the room at this time. "Yes, yes, hold the horizontal bar and push it in a circle - this mill is bigger than the one used to make hand-ground tofu or hand-ground sesame oil at home, so it may be a bit heavy for you." Gong Zhou gave instructions in a low voice, adding more new mineral materials to the grinding hole from time to time.

The grinding wheel used to grind ore is indeed much heavier than the small mills they had seen in shopping malls or various ancient town scenic spots before. But for Bai Miaomiao, a Hanfu contestant who usually pays great attention to the health of her body and often wears clothes weighing more than ten kilograms (bushi), this is not a big problem.

She followed Gong Zhou's instructions and pushed the machine two more times until she got the hang of it. It didn't take much time to grind a small bag of ore. When the bag of ore was completely empty, she still felt a little unsatisfied.

"Okay, after the ore is crushed, the next step is to sift it to select the fine enough powder. The unqualified powder will be sent back for re-grinding." Gong Zhou said as he stretched his head and swept out a small basin of powder ash. "Sieving ash is a very simple step. It is the same as sifting flour when you make snacks at home."

"However, the sieves we use when making purple clay pottery are definitely different from the sieves at home... Here, these are three 100-mesh sieves. The three of you can take them and sift them with me."

"Remember not to shake too hard when sifting the ash, or you might get mud all over yourself."

"Okay." The three girls nodded in unison, and then imitated Gong Zhou and shook the sieve carefully.

The fine enough powder falls through the sieve holes into the iron plate, and what remains in the sieve is the slag that has not been crushed thoroughly enough.

The girls who were playing with this thing for the first time were not very skilled yet, and it took them a whole cup of tea to sift a small basin of ash.

"Don't mention it, sifting with this thing really feels a bit like sifting flour at home." Xu Dazhuo rubbed his hands excitedly, "It's just that the sieve is too big, and the stuff sifted out is not flour."

"Of course, the principle is always the same - there's nothing special about it." Gong Zhou smiled and curved his eyes. "The next step is to add water and mix it. This step is similar to kneading dough, which requires a little experience - after all, we can't add water when there's too much dough, or add dough when there's too much water, so I won't let you guys try it. Pay attention to the movements of my hands."

"The water we mix into the mud in this step is usually 'rootless water', that is, rain water. In this step, the mud should be mixed until it is neither too soft nor too hard, and the mud mass as a whole is not too sticky, but can leave clear fingerprints when pressed."

"Add rainwater!" An Qing blinked. "Teacher Gong, rainwater is so difficult to deal with... Can't we replace rainwater with tap water in this step?"

"Tap water won't work." Gong Zhou shook his head. "Tap water will contain some of the various purifiers used in water purification. These things may affect the color of the finished clay or form salt precipitation on the surface of the pot."

"——Rainwater is more suitable."

I feel Gong Zhou is better at giving lectures than Lan Lan ()
These two chapters are much more comfortable than last year's string rubbing