something wrong w/ that redbossmtea.com gaiwan?Aram wrote:http://redblossomtea.com/details.php?se ... n&item=175
beware...
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ive seem those light blue interior gaiwans b4, the very bottom has a lighter blue than the top portion right? you positive it's the gaiwan? is it new? did u wash it b4 using it? try pouring just hot water in it and drink it, if it's still salty than discard it.
people here r too concern about lean in their tea wares and yet they seem to have no concern using other glaze items...beer bottles, wine glass, plates, wine glass, damn..even toilets are glaze.
people here r too concern about lean in their tea wares and yet they seem to have no concern using other glaze items...beer bottles, wine glass, plates, wine glass, damn..even toilets are glaze.
it's a white spot that came off the side, hot water melted the glaze for sure, the gaiwan tastes fine.not a cascade. I have a new tray for wilted tea leaves (the base) a little pot to grow things (the cup) and a new lid for my japanese pot that shattered. 
i'll try to post a picture if the potting idea works.
i'll try to post a picture if the potting idea works.
May 15th, '09, 11:58
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Joined: Jun 15th, '06, 13:04
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bearsbearsbears
[/img] thanks for the advice. i actually like it as a flower pot. maybe later on... 
i wonder if its just paint then... like watercolors ~ (*^ ^*)
May 15th, '09, 13:18
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hooksie
May 16th, '09, 19:52
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Joined: May 2nd, '09, 05:36
Location: Honolulu, Hawaii
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bonjiri
glazes
hm
interesting topic.
it is very important u ask the potter, if that person is unknown. it becomes an issue.
personally, i mix my own glazes and know exactly what is contained in the recipe. some of the items i don`t use is barium carbonate and manganese dioxide.
most of my glazes range from iron red, celadons, shino and tenmoku which all contain colorants (oxides).
the biggest issue in chemicals leaching is using acidic liquids inside your teaware. most teas are not acidic.
and yes, glaze will not flake off with hot water. but there are some pieces i have seen where the potter has applied crushed`glass`. there a moment in the future where regular glass may pop off the piece. there is a glass terminology called coiefficient. usually glass with unlike coiefficient don`t fit and can crack apart.
my pieces, i use ash which a combination of ash/soda creates silica which i believe fits the clay body/nepheline syenite (shino) glazes better than just applying crushed glass fragments and having it melt.
cheers
bottom line. caveat emptor
interesting topic.
it is very important u ask the potter, if that person is unknown. it becomes an issue.
personally, i mix my own glazes and know exactly what is contained in the recipe. some of the items i don`t use is barium carbonate and manganese dioxide.
most of my glazes range from iron red, celadons, shino and tenmoku which all contain colorants (oxides).
the biggest issue in chemicals leaching is using acidic liquids inside your teaware. most teas are not acidic.
and yes, glaze will not flake off with hot water. but there are some pieces i have seen where the potter has applied crushed`glass`. there a moment in the future where regular glass may pop off the piece. there is a glass terminology called coiefficient. usually glass with unlike coiefficient don`t fit and can crack apart.
my pieces, i use ash which a combination of ash/soda creates silica which i believe fits the clay body/nepheline syenite (shino) glazes better than just applying crushed glass fragments and having it melt.
cheers
bottom line. caveat emptor
May 16th, '09, 20:37
Posts: 109
Joined: May 16th, '09, 20:28
Location: Moss Beach, California
Contact:
Moss
Probably not dangerous
If your chawan is blue interior, it is probably not toxic unless it is quite old (possible lead) or that sort of Bahama Blue you get sometimes, almost turquoise (possible Barium).
I would go buy a home lead testing kit, they are $13 I believe from ceramics supply houses. They contain three tests that are instant read. If you do get that back as positive, I would leave the cup on the shelf but not destroy it or anything.
Barium would be fine if it were in a glaze that was fired to the right temp as it would form part of the glass and not be permeable. Since you say the glaze is wearing off, then I would be a little suspect that it was not fired to full maturity.
BTW, it isn't melting off, they are fired to something like 1800* f or higher. I go to 2345*f so unless you like your tea REALLY REALLY hot, you aren't beginning to melt it.
In short, test for lead and otherwise probably not a problem but you might want to use it for decoration more than drinking.
I would go buy a home lead testing kit, they are $13 I believe from ceramics supply houses. They contain three tests that are instant read. If you do get that back as positive, I would leave the cup on the shelf but not destroy it or anything.
Barium would be fine if it were in a glaze that was fired to the right temp as it would form part of the glass and not be permeable. Since you say the glaze is wearing off, then I would be a little suspect that it was not fired to full maturity.
BTW, it isn't melting off, they are fired to something like 1800* f or higher. I go to 2345*f so unless you like your tea REALLY REALLY hot, you aren't beginning to melt it.
In short, test for lead and otherwise probably not a problem but you might want to use it for decoration more than drinking.
Matt Brown
Moss Beach Ceramics
www.mossbeachceramics.etsy.com
www.mossbeachceramics.com
Available at Teance tea room, Berkeley, California
Moss Beach Ceramics
www.mossbeachceramics.etsy.com
www.mossbeachceramics.com
Available at Teance tea room, Berkeley, California