Stains and leaks (before and after)

[night.owl]

And lastly (for now), my next staining hopeful, after about one week of use. You can just barely see the stains starting. I have a feeling this one will move along quickly, even after spending 300 years undersea!

One week of use.JPG (27.92 KiB) Viewed 875 times

[Chip]

Beautiful pieces! Perhaps your Kashun yunomi is self healing. Not uncommon.

I would think a leaker (or piece that was a leaker) would show crackles faster than one that did not.

[AdamMY]

I think I have said this before, but I honestly feel that each piece takes on a life of its own. Chip likes to say that I somehow stain pieces quickly, but there have been some pieces I have had that have been nearly stain resistant for extended lengths of time.

[IPT]

I love the staining capability of celadon ware. You are so right AdamMy, they really do take on a personality all their own. Each piece crackles and stains differently and the staining is a direct result of your use of them. I love it!

I do have had some pieces that have started to darken after a single use, and others that I have used for years, yet show little to no signs. It is weird.

[night.owl]

Beautiful pieces! Perhaps your Kashun yunomi is self healing. Not uncommon.

A sad possibility... I actually preferred it leaking.

I would think a leaker (or piece that was a leaker) would show crackles faster than one that did not.

One would think so. I'll have to carefully compare it against a photo of the original, but as far as I can tell, there's only some slight staining in some of the deeper cracks.

I do have had some pieces that have started to darken after a single use, and others that I have used for years, yet show little to no signs. It is weird.

DEFINITELY weird!

[Qilin]

Crackles will all stain brown. The same compounds that were not oxidized during the processing of the white tea will oxidize when the tea sits and when it stains the cup as brown as any other tea.

How disappointing! I have been using my new cup. It's still quite white. Well, we'll see.

My dream is to have a whole crackled gaiwan with teacups set.

[bob]

Ha, I was just about to open a similar topic, sort of "show your before/after pictures"...

I do have had some pieces that have started to darken after a single use, and others that I have used for years, yet show little to no signs. It is weird.

Yes, sometimes they stain incredibly fast. I wonder if the initial cleaning/soaking/boiling process has something to do with the staining speed...

Below is a photo of two Hagi cups I recently got from Artistic Nippon. I used the left one for 1 session of Yame Fukamushi sencha, 4 or 5 cups. I didn't notice anything as I cleaned it a few hours afterwards. But when I wanted to use it the next day, I was shocked to discover it was full of crackles! Since I didn't yet get a chance to take a "before" photo, you can compare it with the same but unused cup on the right...

Hagi staining 1.jpg (19.92 KiB) Viewed 782 times

Hagi staining 2.jpg (14.84 KiB) Viewed 782 times

After I got the cups, I washed them with hot water and then put them in a pot and boiled them gently for a few hours. The water was boiling lightly and the cups slowly moved around the pot. In the beginning there was a lot of small bubbles coming out of the pots, but later they stopped. I dried the cups for a day before first use, but I forgot to pre-soak the cup I used, I just warmed it with hot water.

Since the crackles are so small and they appeared all at the same time, I started thinking that perhaps boiling might speed-up the cracking process... If not because of heat, then maybe because of small movements of the cup?

I'm very tempted to use the second cup and see what happens, but I want to keep it as a reference for a while!

[night.owl]

Bob, I wonder if the process of boiling made it easier for the tea to seep into the cracks, with the "inside" clay portion still being moist?

I may have to experiment soon with one of my more stubborn pieces...

[Chip]

That is pretty amazing for only several steeps, but this seems common for Kashun pieces.

I am of the other school of thought. I believe presoaking reduces staining as the crackles are saturated with water instead of tea. I have found my staining to be much slower than others who bought the same piece and did not presoak.

But I still feel a darker tea will stain the fastest.

[AdamMY]

Based on what I have witnessed in the staining of certain pieces, I feel staining progresses the most quickly when a piece is has been water logged for an extended length of time with cold water/tea, and then put into use. I feel the water picks up a bit of coloring from the clay body, and upon the cup being hit with hot water the water in the waterlogged clay body expands and carries the color it picked up from the clay body into the cracks in the glaze as the water expands.

Its just a theory, but considering I have a hard time explaining certain symptoms I have seen in my pieces in the past. Such as weeping when there should be no chance at leaking.

[IPT]

I have had some pieces stain quickly when soaked, and yet others stain quickly when not soaked. I think it depends on the piece. Some of my SO pieces have stained incredibly quickly and I have not presoaked them.

[auhckw]

1 pot of boiling ripe pu
1 pot of ice water with iced cubes

dip the cup into the ice water for 30 seconds
take out then...
dip the cup into the boiling tea for 30 seconds

repeat for many times

Would you dare to try this?

[Ludwig-1954]

No, I would not waste my time on ice cubes and boiling water. For a really "shattering" effect, try liquid Nitrogen instead ...

Apart from this, I have been watching Ru Kiln Celadon (Dongdao and Taiwan Arisanal) develop itsseasoning. In the process, I noticed, that the cups tended to stain "top down", i.e. starting from the brim and not as expected from thebottom. In extreme, the area not covered by tea stained first ...
My reasoning is, that staining has much to do with the capillarity of
the cracks. This would mean, that coarser base material, with larger
expansion/shrinkage will produce wider cracks in the glaze. This, in
turn, will lead to faster and more even staining. And vice versa ...

So far, Dongdao Ru ware does not really stain very nicely and it does show
very even and fine base clay.

[debunix]

In the process, I noticed, that the cups tended to stain "top down", i.e. starting from the brim and not as expected from thebottom.

In my most-used and most-stained cups, the staining is definitely 'bottom up', with the top slowest to stain.

[IPT]

In the process, I noticed, that the cups tended to stain "top down", i.e. starting from the brim and not as expected from thebottom.

In my most-used and most-stained cups, the staining is definitely 'bottom up', with the top slowest to stain.

Mine too tend to stain top down, but a few have gone the other way.