David Woof on fri 2 mar 12
Hi All=3D2C=3D20
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Sumi hits it square on the head re consuming the tea relatively quickly. (t=
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hink time frame for the traditional Tea ceremony for example.)
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In addition to the overnight wet foot factor=3D2C some folks are allergic t=
o =3D
various forms of Boron and so leaching may be a concern in longer term soak=
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ing situations.=3D20
=3D20
see: Toxicity manifests in headaches=3D2C diarrhea=3D2C vomiting=3D2C nause=
a and =3D
skin rash. However=3D2C humans tend to excrete boron very quickly and there=
fo=3D
re high levels are not built up in the blood stream
Article Source: http://EzineArticles.com/4763112
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***Lead!!! dread the Lead!!!*** Even though most folks think they don't use=
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lead anymore=3D3B We still are if we use a lead frit. (an uncomfortable tr=
ut=3D
h to some folks I'm sure!!!)
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Lead frits assure a measure of safety when handling the frit during the gla=
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ze mixing and glazing process=3D2C but does little to mitigate the possibil=
it=3D
y of toxic fumes during firing and lead may still leach from the finished f=
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ired glaze just as any lead glaze could or would. Especially at the lower t=
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emps of low fired raku.=3D20
=3D20
Challenge this after one asks=3D3B 'so why does the government need to set =
st=3D
andards of PPM leachate for vitrified dinnerware?'
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Please don't let this ruin the day or enjoyment of a good healthy bowl of t=
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ea. Just make informed decisions.=3D20
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No one is going to die while savoring a bowl of tea unless they are dying a=
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nyway=3D2C and can one think of a better way to go than over tea with good =
fr=3D
iends?
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Be well all=3D2C
=3D20
David Woof
_______________________________________
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Re: Raku - What makes Japanese tea bowls functional?
Posted by: "Sumi von Dassow" sumi@HERWHEEL.COM Date:=3D20
Fri Mar 2=3D2C 2012 4:13 am ((PST))=3D20
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jemuzu isn't it just the fact that you drink the tea relatively quickly? If=
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you filled them with water and left them on a nice finished wooden table o=
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vernight I'd expect water would leak through and damage the finish. Un-vitr=
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ified pottery doesn't leak like a sieve.=3D20
Sumi>
______________________=3D20
=3D20
I have several Japanse-made raku tea bowls that are perfectly functional --=
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they have no problem holding water. Seriously doubt there's any tung oil=
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=3D2C polyurethane=3D2C silicon=3D2C etc. on them (commonly applied to raku=
-ware =3D
made in the States=3D2C at least). So what is it about the process or mater=
ia=3D
ls that makes this possible? Judging by the almost wooden "thunk" when tapp=
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ed with a fingernail=3D2C I'm assuming they are indeed low-fired. Is it the=
c=3D
lay? Are they using a clay body that vitrifies at a low temperature and can=
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also handle sudden thermal shock? Are they once or twice fired? Is it the =
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glaze? Firing temperature? Firing ramps or length? Quenching in water vs. c=
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ombustibles in a trash can? Please do tell.>>=3D20
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James> =3D
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