The unofficial/official HAGI topic!

[Chip]

I don't need to have my Hagi cured...I need to be cured of Hagi
Chip is going to be no help whatsoever with this affliction

Correct! But I call this affliction more appropriately "cultural exchange." I wonder if we could get a government grant?

[murrius]

I wasn't quite clear, I do warm the cup, but do not allow it to soak. I think the leaking has more to do with how much water the cup had adsorbed. If the cup has absorbed as much water as possible, and more water is added, then it starts to leak, if It hasn't, then it seems that it need to absorb more liquid before it starts to leak. The heat gets absorbed pretty quickly, however.

Like I said, capillary action. If the cup was "cured" of its leak, soaking would likely not cause it to leak. Seems logical.

That makes a ton of sense.

By the way, my Biwa leaked vigorously until I did the Chip patented leak proof hagi cornstarch method. It still leaked, but much reduced, after the cornstarch treatment but disapeared completely after I let it utterly dry again. No such problem since.

[Seeker]

Been thinking about the issue of crazing vs crackling with my sansai wan.
I don't know, but based on GG's comments, I suspect crackling.
Here are a couple of pics.

and a little closer, different light:

Mayhap this is the developmental process of a hagi?
(and again, referencing GG, no corresponding cracks on the outside).
Cheers.

edit/addendum: I had originally suspected/feared crazing because these crackles weren't everywhere as well as sort of uniform, but rather seem to be developing a bit at a time, here and there.

[Chip]

Crackling ... would be my guess, similar here as well. But only brewed sencha, and the crackling is a nice greenish hue, and a bit more uniform and defined. Looks quite attractive and desirable.

[Margules]

That looks fairly normal to me. Over time, you will get more crackling, and the tea will seep into the cracks and start to tint them.

For what its worth, I think the picture GeekGirl posted of the crack that went all the way through was more an example of thermal shock than crazing, which can happen irrespective of glaze.

As far as I know, the only difference between crackling and crazing is whether or not the potter intends for it to occur. In the case of hagi, the difference in the rate of thermal expansion between the clay and the glaze is sufficiently large that crackling is inevitable, and is therefore generally accepted as a feature rather than a flaw.

[Geekgirl]

For what its worth, I think the picture GeekGirl posted of the crack that went all the way through was more an example of thermal shock than crazing, which can happen irrespective of glaze.

Could very well be. Also, it can be confusing because in many cases shock and crazing appear in the same piece. I wish I had a couple of examples of crazing from my grandfather's estate. He had some highly collectible china pieces, that were of fairly low value due to severe crazing. I should have taken some pictures before my mother sold them. They exhibited both crazing and several of those cracks that ran through. A shame.

Worth noting: when you receive a package in the mail, be certain to let the teaware acclimated after unpacking. I let EVERYTHING sit for a full day. It's probably overkill by many hours, but remember that shipping bays get COLD. During certain seasons, it's also very cold in the mail warehouse and on the truck too. Letting it sit on your shelf in your nice warm house for at least several hours might prevent a nasty crack from temperature variations.

(I learned this lesson the hard way.)

[Seeker]

Thanks for all the valuable info!
Home environs acclimation - check! From now on!
Had not thought of that.
Again my gratitude.
This Hagi Padawan bows reverently.

Also, I've only used the sansai for green (sencha only) and white teas.
And my crackles are dark -- the whites? (silver needle, white peony)

[kymidwife]

For me, the crackling only adds to the desireability and character of my Hagi pieces. I hate not being able to see this phenomenon well in the Seigan blue and sea cucumber pieces... and love watching it develop in the lighter-colored pieces. My Deishi white yunomi and kyusu set... they are spectacularly spider-webbing, and I love it so much!

Ahhh perhaps tomorrow I should break out the rainbow pieces. They are pristine, uncrackled, and begging to be used.

Sarah

[Tead Off]

Gusher Biwa, first cornstarch treatment cold, 2nd CS treatment hot. I give it a soak before each use, never leaked again.

I suspect with Ed's, when he soaks his experiences capillary action, when he does not, there is no capillary action due to air filling the gaps.

I think if one approaches the leaker systematically, it can be completely sealed. I had so much fun sealing this Biwa, and a small leak with the Shiro, and 2 leaker Biwa Guinomi with 100% success, that I wish we were all closer as I would enjoy a hands checking these things out.

Chip, what ratio cornstarch to water do you use? How long do you soak in the cornstarch solution?

Strangely enough, I have a bizen vase that leaks. It shouldn't as they are high fired but this one does and I'd like to cure it.

[Chip]

I believe it is one tablespoon per 16 ounces water.

I will double check when I return.

[AdamMY]

For me, the crackling only adds to the desireability and character of my Hagi pieces. I hate not being able to see this phenomenon well in the Seigan blue...

Mind you I only have one hagi right now and it was my go to teacup when I was home for thanksgiving. But I'm noticing the cracks darken in my Seigan blue piece... but I should note that is from 4 days straight of drinking 2-4 sessions of 3-4 infusions each out of that cup.

[Chip]

Tead Off, yeah, 1 tablespoon per 16 ounces. Let me know if you need a more metric conversion. I put it in the vessel versus soaking. Logic tells me it would be better to allow the slurry to flow in the same direction of a leak in order to clog it up?

4-8 hours.

I do not rinse or anything, just pour off the slurry and allow to dry fully for a day +/- followed by hot water and rinsing repeatedly in order to remove the slurry residue.

You can test at this point and re treat if needed.

[Chip]

I have noticed crackling on SO #5 Seigan Blue Wan, again all sencha and green hue to the crackling though much finer than the Sansai Wan. Yet darker glossier Seigan Blues exhibit no crackling to this point ...

A Sea Cuke Wan has similar greenish crackling as well and again finer.

Ahhh, the magic of sencha and green crackling perhaps?

Yet Deishi whites seem darker. I am observing crackling on the Biwa SO #4 ...

[Seeker]

Regarding leakage,
I made matcha in my biwa this morning (two sessions! ).
Head over to "This morning's matcha" for a peak at a pic.
Having read a couple of suggestions that matcha might assist with the leakage, I thought I'd give it a try.
As u know, I've treated 3x w/ cs, and leakage is much diminished, but still leaves a small puddle on my chataku.
So, I'm letting the dreggs of matcha sit in the biwa for a while, then I'll gently rinse.
We'll see what happens.
Cheers.

[Dreamer]

Hey Seeker and Chip,

I noticed yesterday when I had my sansai wan out in the sunshine that it does have crackling/crazing just like your picture, Seeker. I had said before that it didn't have any, but it is just so fine that I had not seen it in typical inside-autumn-day lighing (or maybe I should even where my cheater-glasses when I drink tea )

Now that I know it is there, I'll be checking it our regularly!

Happy Hagi,
Dreamer

P.S. Seeker, beauitful pics of matcha in the leaker in the other thread!