The next morning, Li Su got up very early. Under Cao'er's service, she washed and changed clothes, and read books in her house.

When he was resting for about Mochen, Caoer brought a plate of morning food and told him that the silversmith with the best skills in the business had been recruited and could go to visit the mirror after dinner.

Morning food is a bowl of pork belly cakes with spicy and sour soup. In addition to fish, there are also ginger vegetables and some mutton oil seasoning - it can be roughly understood as sauerkraut fish noodles in later generations.

Looking at this, Li Su also wanted to cry: the food in the small shop that cost more than 20 yuan in the future must be a super rich man like the Mi family, so he used it as a breakfast for guests. Whether it is dogwood or pepper, it is expensive spices.

The reason why the queen's bedroom in Weiyang Palace is called "Pepper Room" is because when the wall is painted white, pepper powder is mixed in putty, which can deworm and remove the smell. It looks very high-class.

Next to the soup noodles, there were also several lacquer plates, with various fish sashimi such as pure white or pink.

The fish sashimi is as thin as a cicada's wings. Guests who like to eat fish can rinse it in the noodle soup with mutton oil, and it will be cooked quickly; they can also eat it directly with dipping sauce next to it.

Li Su only recognized the fish sashimi and ate it raw with a tray.

Fortunately, this is Haigang County. Otherwise, with the preservation technology of the late Han Dynasty, I would not be able to eat such fresh fish sashimi if I walked inland a little.

When I returned to the Han Dynasty, I should recognize the local specialty food wherever I went.

Cherish every time, and you will disappear if you change the place.

But despite this, Li Su only ate fish sashimi, either cooked it or simply kept it untouched - because when he was eating, Cao'er accidentally said something to show off his original intention, which made him frightened:

"When the magistrate of Guangling Chen County came to our mansion to visit, he liked our fish sashimi, and he praised every one of them."

When Li Su heard this, his chopsticks almost fell off the table.

Chen Deng died of eating fish sashimi, and even Hua Tuo could not save him.

...

After eating the "mill-style top sashimi", Li Su wiped her mouth and, under the guidance of Cao'er, came to a craftsman's house in the mansion.

The furnishings in the house are not gorgeous, but there are quite a lot of luxury goods and various tools. At first glance, this room is used to renovate those rare things.

An old silversmith who looked fifty years old, with an apprentice, was repairing and renovating there. There was also a supervisor of the Mi Mansion next to it, which obviously prevented craftsmen from stealing raw materials for repair.

The repair materials used in this kind of work are all gold, silver and gems, so you must be careful.

When Li Su came in, the manager and the silversmith stopped saluting him. Li Sulian said it was okay and signaled them to continue.

Then, Li Su saw the young and strong apprentice of the old silversmith holding two slightly green bronze mirrors, with some water sprinkled on the surface, and they sharpened each other hard. The piece below was fixed with a clamp similar to a whetstone groove, and the piece above was placed on a cloth towel, and the piece above was held in his hand.

"It seems that the polishing of bronze mirrors in this era is to rub each other directly on both mirrors, but in this way, there will be scratches or slight traces of wire drawing in the end, which will not be too smooth." Li Su saw it and thought in her heart.

While thinking, I took the grinded bronze mirror and verified it, and it was true.

The roughness is similar to that of later brushed aluminum molds. It is probably used by maids in the mansion, so it is so simple to deal with it.

Li Su judged in his heart that this technology had no reference or improvement value, and then looked back at the old silversmith's operations.

The old silversmith is much more stable than his apprentice. He first took a finer whetstone and grind it hard for a while. The blackened silver oxide protective film was worn off, revealing the bright white reflective sterling silver inside, but the silver surface was damaged to a little rough.

Then he took a small handful of things that looked very delicate, like flour, dipped them a little water, and applied them evenly on the mirror. Then he skillfully used a piece of delicate silk to wipe along the surface of the silver mirror.

After a while, after at least several coins of silver powder were filed off the ground, the silver surface finally smoothed again so that the human face could be vaguely seen.

During the whole process, the thickness of the silver mirror became visible to the naked eye.

The manager of the Mi family carefully held a silk rag - he didn't even dare to use a broom - roughly wiped the ground of the bluestone slab and applied the silver powder on the ground into a jar to take it back and melt it. However, because the silver powder was too fine and it was a little oxidized, the fire consumption was probably very high.

Seeing this step, Li Su had already roughly understood the core competitiveness of the grinding process in her heart - the key was the pinch of abrasives as delicate as flour.

Although he was a liberal arts student in his previous life, he was still a top student. He was mostly a top student, and he had high myopia. He was only 1,200 degrees of myopia, and he couldn't even use contact lenses, so he could only use frame glasses.

So in order not to be as thick as the bottom of the bottle, lenses with a height are only super thin, and then they are very expensive. So when he was in college, he felt very distressed every time his glasses were scratched because he had no work income.

So he also searched on Baidu for "What to do if the glasses are scratched?", and the lady told him: As long as they are not coated glasses, you can use a little toothpaste and clean water, and apply them to the lenses evenly, and then wipe them hard with the glasses cloth.

He tried it and found that he had actually repaired the scratches of the lens. Although the degree was a little inaccurate and the coating was worn off, it at least extended the service life of the glasses of the poor academic master by several%.

Because it is concerned about his own interests, he specially studied this matter on Baidu. Later he found out that it was toothpaste, a calcium carbonate powder, which plays a grinding role.

He still remembers the relevant data he found online: the grinding accuracy of commonly used sandpaper is only 100~200, and the finest whetstone is about 400. And abrasives with an accuracy of more than 1500 are basically grown into toothpaste, shoe polish, and facial cleanser.

The abrasive used by the old silversmith in front of me is probably also limestone powder, but the Han Dynasty people could not polish the stone powder to a finer level. From the perspective of later generations, it is estimated that the grinding accuracy is at most 500 to 600. No wonder the polished silver mirror is not very clear.

Seeing this, Li Su already knew what he should do: he had to find a way to make "toothpaste".

Of course, this toothpaste is not used to brush teeth, so it does not require fragrances, detergents... these ingredients.

The core is the finest calcium carbonate abrasive as possible, plus lubricant and adhesive. These three materials are made into "toothpaste" and can be ground into the clearest and most durable silver mirror in the world today.

If you really don’t have lubricant, you can just sprinkle water like the old silversmith, but it’s best to have a transparent clean oil. There was no Vaseline in this era, but the ancients could use sharpening oil and phytate oil for the sword maintenance.

The function of the adhesive is to ensure that the abrasive particles are evenly dispersed in the paste and do not clump, otherwise it will still scratch the mirror. The material of this kind of thing, Li Su later saw on the facial cleanser ingredients list, mainly sodium metasilicate - to speak human words, that is, the "algae mud" and "volcanic mud" that are advertised in facial cleanser advertisements.

As a harbor county, Qu County is definitely not able to get volcanic mud, but there is a lot of diatom mud.

During the meal these two days, Li Su ate kelp and seaweed more than once. Although it was not a breeding, it was a wild cargo picked by fishermen, it was still very easy to find a few fishermen to pick a bunch of algae residues back to grind, filter and clarify.

Li Su thought about this, and just like the rest, he walked away. When he was about to stop, he pretended to be careless and said that he had seen a better-grinding silver mirror in the Zhen family's business in Jizhou.

Of course, the old silversmith was dissatisfied, but the craftsman had a humble social status and did not dare to refute Li Su in person, so he let Li Su leave.

This can be regarded as the preparation for Li Su to come up with a better silver mirror in the future.

...

It wasn't until noon after leaving the silversmith. After half a day, Li Su simply found several of his own soldiers and went out to buy some things - not all of them were necessary for making abrasives, and many of them were smoke bombs that were used to protect them, and they were not used at all.

However, these miscellaneous materials are not expensive, so it is not a pity to waste them.

And it was also a gift from God - the most core experimental raw material, quicklime, doesn't need to be bought now. Because when I passed by Pengcheng a few days ago, Guan Yu bought a lot of quicklime to pickle the heads, and there were still a few packs of them not used up and put them in his luggage.

Therefore, Li Su's confidentiality work is perfect. Even if someone notices that he has taken out a high-end silver mirror in the future, he will not find out the most core material of quicklime.

In addition, Li Su also asked his personal soldiers to occupy a deserted temple outside the city because he did not want to conduct scientific experiments at Mi Zhu's house. (Now there are no Buddhist temples or Taoist temples in Huaiyang area. The temples are all sacrificed to Taiyi God. Huaiyang's Buddhist temples were later spread wildly by the Danyang warlords.)

It was during this preparation that Li Su made another discovery - he originally wanted to buy sharpening oil as grinding lubricant, but later he found that the blacksmith at the end of the Han Dynasty had not yet used the concept of "sharpening oil".

In other words, today's iron armor and iron weapons do not have grease to prevent rust. They all expect that after the surface is formed with oxide or sulfide protective layers on the surface, the inner layer will no longer be corroded. (The blacksmith will use a certain amount of grease when forging and quenching, but no one will use the sharpening and maintenance links after leaving the factory.)

No wonder most of the iron armors today are "black armor", because the rust and dense oxide layer of black dust can protect the iron inside. The bright armor is more used as a ceremonial guard.

The horse-slashing sword and the ring-headed sword do not have the shiny and smooth blades of the later swords, and the colors are quite dark.

Fortunately, Li Su finally found a barely available phytic acid oil. Anyway, as long as it is acidic vegetable oil, it has certain antioxidant effects and has a clear and transparent eye color, it can be used to grind and protect silver mirrors.

This incident also reminds Li Su that in the future, you can buy more phytic acid oil that meets this kind of conditions to apply weapons and armor to the army. Although it cannot improve the combat effectiveness of the equipment, it can definitely increase the durability of the equipment a lot.

The weapons of other warlords will decay into scum within seven or eight years at most, and Li Su's troops may have twice the wait time.

After working hard for a long time, I finished the two things that were filtered and cleared, and phytic acid sharpening oil.

Li Su is preparing to personally deal with the last and most core material - a fine enough calcium carbonate grinding base.
Chapter completed!