Yixing

[Youzi]

The problem comes from the mix of these. And especially acid cleaning of teapots, which is also in use for a long time.

Very good information to know Youzi. Curious what kind of acid wash and why was it used?

There's Two kinds of acid used during water mixing phase of clay processing, referred to as strong and weak acid washing. The strong one uses H2So4 Sulfuric acid, the weak one HCL Hydrogen Chloride.

These acid washing is used for "cleaning" the clay, so there won't be "impurities" left there after firing, such as burn holes, black iron spots, etc.

[DailyTX]

The problem comes from the mix of these. And especially acid cleaning of teapots, which is also in use for a long time.

Very good information to know Youzi. Curious what kind of acid wash and why was it used?

There's Two kinds of acid used during water mixing phase of clay processing, referred to as strong and weak acid washing. The strong one uses H2So4 Sulfuric acid, the weak one HCL Hydrogen Chloride.

These acid washing is used for "cleaning" the clay, so there won't be "impurities" left there after firing, such as burn holes, black iron spots, etc.

@Youzi
Your knowledge is very informative. I was encouraged to buy pots with impurities when I first started the yixing zisha journey. As I interacted more with different pots, I noticed most people buy pots based on their first impression while experienced buyer will look for the dynamic of clay, color tone, and impurities as an added characteristic to the pot. I am more familiar with Zini with those features. With limited experience dealing with hongni and luni, do you know if this rule also applies to hongni and luni?

[Youzi]

Very good information to know Youzi. Curious what kind of acid wash and why was it used?

There's Two kinds of acid used during water mixing phase of clay processing, referred to as strong and weak acid washing. The strong one uses H2So4 Sulfuric acid, the weak one HCL Hydrogen Chloride.

These acid washing is used for "cleaning" the clay, so there won't be "impurities" left there after firing, such as burn holes, black iron spots, etc.

Youzi
Your knowledge is very informative. I was encouraged to buy pots with impurities when I first started the yixing zisha journey. As I interacted more with different pots, I noticed most people buy pots based on their first impression while experienced buyer will look for the dynamic of clay, color tone, and impurities as an added characteristic to the pot. I am more familiar with Zini with those features. With limited experience dealing with hongni and luni, do you know if this rule also applies to hongni and luni?

These impurities are a requirement, if you want to get a pot with the least amount of chemicals added.

It should apply to all pots. Zhuni, hongni less so, because they are fired at a lower temperature. Zhuni is sieved at a very high Mu, so most of such "faults" which are signs of a natural clay are eliminated.

However, "zhuni" has the most stuff added to it compared to any other kind of clay. And it's the most difficult to find out about them.

However, you should expect that ANY, ALL teapot since 1980, has Barium carbonate added to them, which are easily available from the market and not made by masters, the amount should vary.

[Chadrinkincat]

@Youzi

Not to rehash the FB thread but would this acid washing be one factor that’s changed since 2010?

What negative effects does this process have on teapots or health? Dr. Lu has mentioned this along with BC but I haven’t come across much in-depth discussions about how it effects either.

[Youzi]

Youzi

Not to rehash the FB thread but would this acid washing be one factor that’s changed since 2010?

What negative effects does this process have on teapots or health? Dr. Lu has mentioned this along with BC but I haven’t come across much in-depth discussions about how it effects either.

I just double checked the sources regarding the 1980 date, which turned out to be correct, so as you pointed out (didn't know GL lasted until 86, thought its till end of 70 or 82), green label after 80s can contain barium carbonate, as 1979-1980 was the year when F1 started to add it to their clay mix. For reference please check Ben Chen's research about Yixing Chemicals, as that's the most extensive and scientific research done regarding the topic. https://www.facebook.com/groups/2179755 ... 540322482/

Acid washing is still a thing, but mainly in lower grade teapots. The only chemical still used in higher grade teapots is low amount of Barium Carbonate. Because usually people who buy pots in that price range know the "faults" which are signs of quality clay. But they are still uneducated, and cannot accept Flower/Wind Glaze.

I'm not a chemist or a doctor so I'm not qualified to answer that. I simply do research regarding Yixing, especially modern ones, because there are too many misconceptions in the west, and over repeated false facts. While there are many experts regarding F1 period, so it didn't need another one.

I'd be more worried about the combined use of all these chemicals together and their unpredictable outcome, but I don't think they'd have too big of an effect, or anything sudden, on your health, which you could directly relate to the teapot. -- Opinion

I don't want to give opinions to people, just the facts, from which they can make their conclusions.

[.m.]

I just double checked the sources regarding the 1980 date, which turned out to be correct, so as you pointed out (didn't know GL lasted until 86, thought its till end of 70 or 82), green label after 80s can contain barium carbonate, as 1979-1980 was the year when F1 started to add it to their clay mix. For reference please check Ben Chen's research about Yixing Chemicals, as that's the most extensive and scientific research done regarding the topic. https://www.facebook.com/groups/2179755 ... 540322482/

Acid washing is still a thing, but mainly in lower grade teapots. The only chemical still used in higher grade teapots is low amount of Barium Carbonate. Because usually people who buy pots in that price range know the "faults" which are signs of quality clay. But they are still uneducated, and cannot accept Flower/Wind Glaze.

Very interesting. Thanks for sharing.
What is "Flower/Wind Glaze"?

[Mark-S]

My newest acquisition

It's the smallest teapot I own. Unfortunately, I forgot to check the size.
I think it is 40ml or something like that. (I can tell you the size next week if you are interested.)

What do you think?

[Mark-S]

More images...

[Mark-S]

And a last one...

[Chadrinkincat]

@Youzi

Thanks for the link, I’ll read up on it.



As far as misinformation in the west goes, it’s still a lingering problem though it’s improved quite a bit since 2008-09 when I first go into tea. Occasionally I go back and read some of the old teachat post from this period just to see how far we’ve come.

[Chadrinkincat]

@Mark-S

Some of the details on this little pot look 70’s to me. Post some more pictures once it arrives.

[Mark-S]

Mark-S

Some of the details on this little pot look 70’s to me. Post some more pictures once it arrives.

Thanks, it looks similar to a green label teapot in my collection, so you are probably right. From what angle would you need more pictures? I already got this teapot, but it is at my parents house. Next week I could take more pictures, when I am going to visit them. It cost $55 and came together with an old black wooden stand. The seller told me that the teapot would be from the 19th century, but this is probably bs. I am happy with this purchase, because these small sizes are very hard to find in Europe and the clay seems fine.

[Mark-S]

This is the similar green label teapot. It is not that small and came with a set of teacups and a plate.

[Mark-S]

More pictures...

[Baisao]

@Youzi, what is “wind/flower glaze”?