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by Herb_Master » May 29th 09 1:01 am

The talk about drawing water from the top, from the bottom above the tap below the tap - is stretching my mind to places it feels unsure of :shock:

How would an old fashioned water jug with pouring spout - assuming it had a cover and a plug for the spout when not in use - compare?

Such as

Image


Maybe this shape is the challenge ColoradoPu has been looking for!
http://cgi.ebay.com/FRENCH-POTTERY-OIL- ... 7C294%3A50

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Re: Oxides

by Tead Off » May 29th 09 2:04 am

Moss wrote:"Adding iron oxides do nothing but change the color. "

Not true. Adding oxides modify the interface between the clay and the interior. If that iron is in glass formers, then it acts as a colorant and forms a glaze, if it is NOT in enough glass former to create a glaze, then the iron oxide is simply iron on the inside of the pot which is what you want for this test.

Iron in the clay and iron applied to the outside are identical chemically. If the clay is totally vitrified, no water is going to enter it anyway. The chemical changes in the water from ionization or whatever are going to occur in the interface between the clay and the water. So if you modify the interface of the interior to be iron, you are going to get the best possible interface between the iron and the water. Bet you a dollar on that.

If you add iron oxide thickly enough and reduce, you end up with iron on the inside of the pot. Just like a tetsubin.

If the desirable mineral is not iron, then it won't matter of course, but if it is iron, that will do the trick.

Now regards other clays, the combination of firing and maturity may be the key. If the iron is only part of the issue, then a clay that is reduced, but not fired totally to maturity, it may remain porous enough to create more surface area for the water to exchange with the other minerals in the clay.
According to Hojo's analysis, this is what he says on the subject:

'100% of Tokoname red clay is made of mixing iron oxide. The melting temperature of mechanically ground iron particle is much lower than naturally existing iron granule. Usually they start melting at around 800 degree C, while natural iron granule can stand until 1300 degree C.'

I asked him this question in regard to the difference between Tokoname clay and banko clay. I then asked him about Sado red clay.

'In fact, tokoname red clay and sado red clay is almost the same in terms of mineral composition. With the modern techinich, people can easily analyze the mineral compornent in clay. The major difference is particle structure. The natural red clay contains crystalized iron granule which is very solid and in round shape (less surface area), while artificially mixed red clay contains iron oxide which was mechanically ground from iron. The particle shape and size of mechanically ground iron is very uneven which has very big surface area. It is just like the relationship between diamond and carbon powder. Due to the big surface area and none-crystal form, mineral can not stand until high temperature baking. It starts melting at 1150degree. As for Sado red clay, they can stand until 1350 degree. With higher baking temperature, clay shurinks a lot and drastically increases its surface area.'

Moss, this is why there is so much doubt about the current yixing wares. They have oxides mixed into the clay to color them but do nothing to the effect they have on water. Pure, high iron clay is the way to go, IMO.

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by chicagopotter » May 29th 09 4:57 am

What about using terracotta fired to a higher temp -- cone 1 (approx 2100F/1154C) or slightly lower? The body will still be mature but not as tight as a high fired stoneware.

coloradopu and other makers -- Did you know that yixing clay is available from Chinese Clay Art: http://www.chineseclayart.com/mall/c110 ... erials.asp Don't know if it is the "real deal," but would certainly be worth investigation if interested.

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by coloradopu » May 29th 09 7:59 am

Posted: May 29th '09 1:57 am Post subject:

--------------------------------------------------------------------------------

What about using terracotta fired to a higher temp -- cone 1 (approx 2100F/1154C) or slightly lower? The body will still be mature but not as tight as a high fired stoneware.

coloradopu and other makers -- Did you know that yixing clay is available from Chinese Clay Art: http://www.chineseclayart.com/...erials.asp Don't know if it is the "real deal," but would certainly be worth investigation if interested.
ibet you would do better just doing it with the clay at hand. if it is a type with higher iron than lets say porcelain then it would be a good candidate to test. i bet if it were unglazed it would be even better. no tera sig or slip just raw clay. vertify it and test for water leaks then test for taste.i have one now that needs a lid and i will do it without a liner glaze and see what happens. i got good feelings about this one and i will try to get some rain water and bamboo charcoal too boot .

i will test the water in the jar with an orp meter then a ph and then a ppm meter. then wait a day/week and test again to see if there are any measurable physical changes in the water. wish i had an O2 meter i would check it too. i want to know if the orp is high enough to leach the iron i bet O2 is needed too but with the ph i bet if after a week i could increase it to increase the orp " oxidation reduction potential meter" i can get the iron to rust out to a point i can read it on the ppm meter. "parts per million / water content tester" non of this equipment is high tech or very accurate but if i can get a change in the readings then yaahoooo! i also figure rain water to be high in ph with all the talk of acid rain but well its gata rain first.


good luck and just make it and put it on the shelf so wee can all see it.

this is cool stuff

a herbmaster check out the clips here latest teapot stuff. will have no inner glaze. same idea as the water jugs.


http://www.justin.tv/clip/e02e264d7cf2c968

will post latest jug with spring time written in Chinese on it.

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by Moss » May 29th 09 6:18 pm

OK, that is information worth having, however I have 7 different sources and types of iron oxide from machine ground to natural (some, magnetite (Fe3O4) is the texture of fine sand, so there are large amorphious particles). The particle size and shape IS important to the make up of the body, not to the finish in this case because in reduction it all turns to FeO and fuses into one piece like a hematite bead.

With an oxide alone in the interior of a pot, you are getting a pure layer of, in effect, cast iron. There won't be much interface with the clay at all for the water once it is finished. In effect, the outside is a jar, the inside is a tetsubin.

This discussion is only for the water storage because we think that iron will help the water. It is not for the teapot itself which is much more complicated. On that issue I do defer to having the right clay or creating a body with the right oxide from the right source.
Matt Brown
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by coloradopu » May 29th 09 7:06 pm

hay moss i like were you are headed with this but i got a few questions.

is a hematite bead going to be permeable to water enough to aid in oxidizing the Fe and allow it to leach. i think the ultimate goal here is to leach iron into the water at a slower rate than lets say letting h2o sit in a tetsu for a day or 2. i think a pure iron "interface " would be too speedy. i think the porosity of the clay might be like a rung out sponge with some iron in it. the next idea of mixing oxides into the clay has my interest.
after digging holes all over the country from sea to shinning sea in pursuit of gold one runs into a lot of natural iron minerals. that said i have a lot of them sitting in water pans buckets etc. and the one in water do rust all-be-it to varying rates and degrees. i find that in particular the pyrite which is gold barring rusts the most.

so it is my idea not to reduce the iron laden materials to a point which they will not oxidize readily but to try to keep them in a moderate amount throwout the clay allowing it to sponge water and and i think particle size does matter in the final product. if too fine its like compacting the sponge to a point i guess which will provide more contact points but less water to aid in the reaction.

it seams that people are worried about the use of machine ground iron stuff. well in the digging of holes i always seem to find gold and with it magnetite and hematite both which are magnetic. easy to separate them then dry and sieve to what ever mesh . if the addition of natural ingredients to the clay is an issue which i think it is. then i guess it will be a needed test to find which particle size keeps the body open enough to allow the natural oxidation of iron to occur and which one "i think pyrite" will do it in a timely but not too quick manner.

i would like to see a pot with a pure iron liner and one with it on the outside all rusted and the inside unglazed i bet it would be a sight to behold. and what a thing to have on a stove outside. i really like the idea.

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by Moss » May 29th 09 7:41 pm

Well I certainly think it's interesting to try and I will with a number of coatings and inclusions as necessary.

I don't think there is an issue of permeability for the iron as it is going to be exposed to water and the water, an acid, will oxidize it from the outside, won't need to permeate the vessel walls.

Now someone here said they wanted a cast iron pot to condition the water. is that too fast? If so, that will make this pot too fast as well.

Colorado, you want to work on some tests too? We can do a lot of small "vases" with different amounts of iron both in the body and coating and then have one person test them out? See if any works? Maybe then send them to another person and have them test the same way and see the results?

Be interesting I think.

I have access to 7 sources of iron oxides of various sorts, 4 are artificial (they let iron rust in certain conditions and then harvest and grind that) the others are natural. I also have access to loads of clay bodies all of which have artificial Iron oxide in them to my knowledge. I don't know if RedArt has artificial Fe in it or not. If it didn't then you could mix that into a body easily.
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by Moss » May 29th 09 7:44 pm

If you do test, then beware of high concentrations of Ilmenite which may contain Manganese in high enough quantities to be a problem. As a colorant, its fine but if it were in high concentrations might be a problem.
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by coloradopu » May 29th 09 8:07 pm

Moss Posted: May 29th '09 4:44 pm Post subject:

--------------------------------------------------------------------------------

If you do test, then beware of high concentrations of Ilmenite which may contain Manganese in high enough quantities to be a problem. As a colorant, its fine but if it were in high concentrations might be a problem.
good point will have to check out the color of the oxidation in the pan to be shure purple bad red good

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by Tead Off » May 30th 09 5:22 am

Moss wrote:OK, that is information worth having, however I have 7 different sources and types of iron oxide from machine ground to natural (some, magnetite (Fe3O4) is the texture of fine sand, so there are large amorphious particles). The particle size and shape IS important to the make up of the body, not to the finish in this case because in reduction it all turns to FeO and fuses into one piece like a hematite bead.

With an oxide alone in the interior of a pot, you are getting a pure layer of, in effect, cast iron. There won't be much interface with the clay at all for the water once it is finished. In effect, the outside is a jar, the inside is a tetsubin.

This discussion is only for the water storage because we think that iron will help the water. It is not for the teapot itself which is much more complicated. On that issue I do defer to having the right clay or creating a body with the right oxide from the right source.
Interesting idea about the inside being like a tetsubin. This brings up a very real practical question. Tetsubin need to be dried immediately after use as rust is very quick to form. How to prevent this?

The question of speed in changing water is not an issue, I believe. The change to the water happens immediately but there might be some issue with volume vs time. Tea water put in a banko cup will change on the spot. A 3L jug of bankoyaki? Maybe Intuit, a poster with knowledge of water, can address this.

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Re: Water Jars

by Jayaratna » Jan 17th 11 4:08 pm

Dear tea-friends,

I have read this full post and am wondering about the results of your tests. Water in my area is really bad and I need to filter and condition it someway. I'm thinking of buying a 3-5 liter water jar, but I don't trust the only ones that would be available here (glazed and decorated ones): probably at best they won't affect the water, at worse they could poison it. Just wondering about your opinions after so much time.

Thank you,
A

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Re:

by JBaymore » Jan 17th 11 5:39 pm

Tead Off wrote:Both are reduction fired changing the iron content from fe3 to fe2.
With due respect........

Typically during the early stages of the firing of ceramics, the kiln is run in an oxidizing atmosphere. This is typically up until about 1500-1700 F for most situations. During this period any iron compounds that are not already in the stable state are typically oxidized to Fe2O3, which has a red color (as in rust :wink: ).

This clean firing process in the early stages is typically necessary for many different reactions to go to completion within the clay body. Not having this can cause defects in the clay bodies. (Sometimes all of this stuff is taken care of in the clean oxidized "bisque" firing, or sometimes is it accomplished as the front end of a single firing process.)

The reduction firing process for high fired wares (2350-2390 F) ) typically have conditions created to allow reduction reactions to start somewhere about 1500 - 1700 F. During this time when the kiln is deliberately starved for oxygen relative to the fuel content, the fully oxidized iron compounds in the clay (and glazes) are "reduced" (chemist's term meaning to remove oxygen from a compound) to the FeO state (typically a grey to black coloration). In rare cases excessive and prolonged reduction can create tiny nodules of Fe.....but this typically is not desireable.

I don't do ironwoirk... so cannot comment on the genesis of that casting process.

best,

..........john

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Re: Water Jars

by Tead Off » Jan 18th 11 5:04 pm

John,

This info I mentioned was gleaned from Hojo in discussions with him about the reduction process used on Bankoyaki and tetsubin. He talks about this on his website, too. I have no way of knowing how accurate it is or isn't. But, he is so admant on this reduction from Fe3 to Fe2.

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Re: Water Jars

by Drax » Jan 18th 11 5:18 pm

You guys seem to be in agreement?

Fe3 and Fe2 refer to oxidation states (sometimes listed as Fe(III) or Fe3+).

So going from Fe3 to Fe2 is indeed a reduction.

The oxidation state of Fe in Fe2O3 is 3+.
The oxidation state of Fe in FeO is 2+.
The oxidation state of Fe in metallic iron is 0.

Hope that helps clarify...

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Re: Water Jars

by JBaymore » Jan 18th 11 7:15 pm

Drax wrote:You guys seem to be in agreement?

Fe3 and Fe2 refer to oxidation states (sometimes listed as Fe(III) or Fe3+).

So going from Fe3 to Fe2 is indeed a reduction.

The oxidation state of Fe in Fe2O3 is 3+.
The oxidation state of Fe in FeO is 2+.
The oxidation state of Fe in metallic iron is 0.

Hope that helps clarify...
That is correct. The Valency numbers are like that.

best,

.........john