和訳は英文の後にございます。/ The Japanese translation is below the English text.

Ceramic Repair

Table of contents

1. Cracked plates
2. Ceramic repair using milk
3. Rice water
4. Japanese methods
5. A planned leakage of coffee
6. “Kan’nyuu”
7. Old plates

1. Cracked plates

At a nearby antique/collectibles store, I bought a couple of dinner plates with pretty birds–looking like a kind of thrush–painted inside.

[Click to enlarge / 写真をクリックすると拡大します] It is a set of plates with depth just enough for pasta sauce. / パスタソースにちょうどいい深みのあるお皿です

When I brought them home and washed them, cobweb-like very fine lines suddenly appeared all over the inside of the plates. Many cracks were in the inside where the birds were painted. Fortunately, the cracks didn’t reach the back.

I wondered if the plates would be broken soon or we could still use them. Whether I would use them for eating or just as a wall decoration, it must be better to reinforce them. So, I went on the Internet to search a method to repair ceramic with cracks.

Soon I found an American website saying “You can use milk and repair cracks on ceramic.”

I wondered if it was true, but I tried; the only ingredient I needed was milk. It went well.

2. Ceramic repair using milk

The method was immersing the plates in a lot of milk and simmering over the stovetop for about one hour. Then I let them cool and washed them, that was it.

The science behind it is that casein in the protein in milk changes into natural plastic by heat, and goes into the cracks and hold them fast.

I have used these plates six times or so since the milk bath. At the time, they both looked OK.

It seems that the cracks have occurred only in the layer of the glaze. We can still see colorless fine lines. However, the water doesn’t go into them any more when we wash.

According to the website, this milk method works not only on cracks but also on broken ceramic pieces. Not something totally shattered, but such things as a plate broken into two or a mug with a broken handle, I think, because they tell you to hold the pieces together with rubber bands and cook in milk for an hour.

3. Rice Water

It is not with milk, but in Japan, there are traditional methods of repairing or reinforcing ceramic.

One of them and available to anyone is using the water in which you wash your rice before cooking. The water is clouded with white color since it contains fine particles of rice. Let me call it “rice water”.

Usually, we discard rice water and add fresh water in the pot to cook rice. But some people don’t discard rice water but keep and use it in such ways as to give plants water with nutrients, to wash their face with very mild exfoliation, and to reinforce ceramic.

4.  Japanese methods

Depending on the potting soil, ceramic vessels can have many tiny holes on the surface. When you put liquid in it, it goes into the holes. Particularly, unglazed ceramic such as a terracotta plant pot absorbs water well. As time goes by, the absorbed liquid can expand the holes and at times, eventually, break the ceramic.

Therefore, in olden days, people said you should cook the ceramic vessels in rice water first thing after purchase. It is because when heated, the miniscule rice particles in the rice water become glutinous, go into the crack and seal the holes. When you buy a big ceramic pot, you put rice water in it and cook on the heat, thereby sealing the inside surface.

When I was small, my mother would say, “We sometimes used cooked rice grains as a substitute for glue.” And I tried with Japonica rice that we had at home. For sure, you can seal an envelope if you squash a few cooked rice grains with your fingers, rub them on the flap and dry. I guess rice particles in rice water become glutinous and then hard in the similar way.

Ceramic repair with gold
A coffee mug repaired with gold / 金継ぎマグ

Another well-known Japanese way to repair ceramic is “kin-tsugi (repairing with gold)”. It is not a method for families but for trained artisans. They repair valued ceramic bowls and plates using pure gold! Sometimes, the vessel looks even more interesting and artistic with the golden lines which put the pieces together.

5. A planned leakage

During a conversation about the rice water method, someone told me about an interesting coffee mug.

The mug was an expensive ceramic vessel hand-made by a Japanese artist. Her company had bought it for “when a very important client visits.”

However, when they poured coffee into the brand-new mug, the coffee leaked from the surface of the mug. They remembered the explanation of the artist, and didn’t complain. As they repeatedly poured coffee, it stopped leaking. It was because the coffee grounds went into the tiny cracks and holes on the surface and sealed them.

The artist had made the mug so that the prospective owner could “participate” in and completes the making of the mug by using it. I thought I would feel very attached to it if the mug was mine.

This story reminds me of “bonsai”. When a master artisan prepares a plant as a bonsai and delivers it to you, it is usually incomplete and under development although it already looks beautiful. He cultured the plant carefully calculating the time so that after the delivery, certain time will pass and make those planned changes happen. And only after that can you fully see the original image of the artisan. Sometimes, it takes decades for it to happen. This coffee mug sounds a little like a bonsai.

6. “Kannyuu”

The glaze shrinks on the pottery and makes the cracked pattern. / 釉薬は陶器の上で縮んで、ひび模様を作ります

Some people asked me if the cracks of my bird plates were “kan’nyuu”.

I didn’t understand, and learned that it’s a kind of decorating technique of ceramic practiced in such places as China and Japan. The artisans make cracks purposefully so that they cover the surface, looking like a pattern.

You can use the kan’nyuu technique only for glazed pottery. The reason is this is a technique utilizing the difference in the contraction rate of the baked glaze and the potting soil.

To make the crack-like pattern stand out, they usually don’t paint images and patterns where they will put kan’nyuu over it.

This is my mortar. / これは私の乳鉢です

Pottery with “kan’nyuu” can be very expensive, but not always so. Actually, after I began to write this post, I found kan’nyuu on my favorite set of mortar & pestle in my kitchen. A couple of years ago, I bought it in Japan from a peddler (for about thirty dollars). You may have one in your kitchen, too.

As for my new plates, I think time and use have made the cracks since the birds are hand-painted and they are made in Portugal.

7.Old plates

Only after six or seven times of use, my plates have had a new couple of thin cracks again on the surface. I am disappointed; it has not been even a month since I treated it with milk.

I wondered if the cracks in the glaze kept increasing as I used, washed, and stacked them; if people had to cook their dear plates in milk periodically; and if people in olden days would thus take care of their pots and plates in general?

When I told this to a French lady who has been teaching cooking classes and holding parties for decades in her home (which means who has a lot of plates), she said,

“I have been using cracked plates for thirty years, and they are just fine for me!”

I wonder if I didn’t have to do anything after all.

[End of the English text]














































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