Personal Gmail on fri 2 mar 12
Hello-I have been following the discussion about cadmium.=3D20
I look at some of the commercial underglazes that are labeled as food safe =
a=3D
nd also safe for studio use including studios open to small children. So I=
w=3D
ould expect these glazes to be very safe. If I am nit mistaken, these unde=
r=3D
glazes and glazes include mayco stroke and coat reds and amaco velvet reds.=
=3D
Do these contain encapsulated cadmium and hoe does the use of these glazes=
f=3D
it into this discussion?
Any info is always appreciated. I am using my iPhone so please excuse any =
a=3D
utocorrections it decided to make that I did not catch. Thx, Mary Jane
Sent from my iPhone=3D
Ben Morrison on sun 4 mar 12
I like your book Ron, I'm currently using a couple of the glaze bases for m=
=3D
y cone 6 work. The chrome/tin red recipe is spectacular. I had no idea the =
=3D
ratio of tin required for good chrome reds was so high, but indeed with som=
=3D
e basic line blend testing you can see the color change with the additions =
=3D
of tin.=3D0A=3D0A=3D0A________________________________=3D0A From: "ronroy@C=
A.INTER.=3D
NET" =3D0ATo: Clayart@LSV.CERAMICS.ORG =3D0ASent: Sund=
ay, =3D
March 4, 2012 2:23 PM=3D0ASubject: Re: Commercial red underglazes=3D0A =3D0=
AHi Ma=3D
ry Jane,=3D0A=3D0AThe only materials controlled by law are lead and cadmium=
so=3D
=3D0Atheoretically any glazes without them could be called food safe - so=
=3D0At=3D
he term becomes useless from that point of view.=3D0A=3D0AMany commercial g=
laze=3D
s are not stable - or durable - so - if that is=3D0Awhat you are asking the=
a=3D
nswer is no.=3D0A=3D0AOur book covers all this in a very understandable way=
and=3D
the=3D0Ainformation applies to all temperatures.=3D0A=3D0AIf I can see a r=
ecipe =3D
of a glaze I can give a fairly accurate estimate=3D0Aof it's durability - w=
it=3D
h commercial glazes you will need to have them=3D0Atested or do the testing=
y=3D
ourself.=3D0A=3D0ALet me know if you need more.=3D0A=3D0ARR=3D0A=3D0AQuotin=
g Personal G=3D
mail :=3D0A=3D0A> Hello-I have been following the dis=
cuss=3D
ion about cadmium.=3D0A>=3D0A> I look at some of the commercial underglazes=
tha=3D
t are labeled as=3D0A> food safe and also safe for studio use including stu=
di=3D
os open to=3D0A> small children.=3DA0 So I would expect these glazes to be =
very=3D
safe.=3DA0 If=3D0A> I am nit mistaken, these underglazes and glazes includ=
e ma=3D
yco stroke=3D0A> and coat reds and amaco velvet reds.=3DA0 Do these contain=
enc=3D
apsulated=3D0A> cadmium and hoe does the use of these glazes fit into this =
di=3D
scussion?=3D0A>=3D0A> Any info is always appreciated.=3DA0 I am using my iP=
hone s=3D
o please=3D0A> excuse any autocorrections it decided to make that I did not=
c=3D
atch.=3D0A> Thx, Mary Jane=3D0A>=3D0A> Sent from my iPhone
ronroy@CA.INTER.NET on sun 4 mar 12
Hi Mary Jane,
The only materials controlled by law are lead and cadmium so
theoretically any glazes without them could be called food safe - so
the term becomes useless from that point of view.
Many commercial glazes are not stable - or durable - so - if that is
what you are asking the answer is no.
Our book covers all this in a very understandable way and the
information applies to all temperatures.
If I can see a recipe of a glaze I can give a fairly accurate estimate
of it's durability - with commercial glazes you will need to have them
tested or do the testing yourself.
Let me know if you need more.
RR
Quoting Personal Gmail :
> Hello-I have been following the discussion about cadmium.
>
> I look at some of the commercial underglazes that are labeled as
> food safe and also safe for studio use including studios open to
> small children. So I would expect these glazes to be very safe. If
> I am nit mistaken, these underglazes and glazes include mayco stroke
> and coat reds and amaco velvet reds. Do these contain encapsulated
> cadmium and hoe does the use of these glazes fit into this discussion?
>
> Any info is always appreciated. I am using my iPhone so please
> excuse any autocorrections it decided to make that I did not catch.
> Thx, Mary Jane
>
> Sent from my iPhone
ronroy@CA.INTER.NET on mon 5 mar 12
Hi Ben,
An interesting story goes with that red - John Hesselberth (co-author) =3D2=
0
did most of the work on those glazes - called me one day and =3D20
complained he could not get the red to work and did I have any =3D20
suggestions. I had heard somewhere - that the ruby crystals needed =3D20
some thing to get started on during cooling (seeding a glaze with =3D20
unmeltable crystals helps crystals get started.) John was using EPK so =3D2=
0
I refomulated with a ball clay in the hopes there would be something =3D20
in it to help - and it did. Probably would have worked with rutile as =3D20
well.
I must say I find the study of glazes and clays fascinating - I'm =3D20
continually tempted to encourage all potters to read the Hammer =3D20
dictionary - a wonderful non fiction read.
RR
Quoting Ben Morrison :
> I like your book Ron, I'm currently using a couple of the glaze =3D20
> bases for my cone 6 work. The chrome/tin red recipe is spectacular. =3D20
> I had no idea the ratio of tin required for good chrome reds was so =3D20
> high, but indeed with some basic line blend testing you can see the =3D20
> color change with the additions of tin.
>
>
> ________________________________
> From: "ronroy@CA.INTER.NET"
> To: Clayart@LSV.CERAMICS.ORG
> Sent: Sunday, March 4, 2012 2:23 PM
> Subject: Re: Commercial red underglazes
>
> Hi Mary Jane,
>
> The only materials controlled by law are lead and cadmium so
> theoretically any glazes without them could be called food safe - so
> the term becomes useless from that point of view.
>
> Many commercial glazes are not stable - or durable - so - if that is
> what you are asking the answer is no.
>
> Our book covers all this in a very understandable way and the
> information applies to all temperatures.
>
> If I can see a recipe of a glaze I can give a fairly accurate estimate
> of it's durability - with commercial glazes you will need to have them
> tested or do the testing yourself.
>
> Let me know if you need more.
>
> RR
>
> Quoting Personal Gmail :
>
>> Hello-I have been following the discussion about cadmium.
>>
>> I look at some of the commercial underglazes that are labeled as
>> food safe and also safe for studio use including studios open to
>> small children.=3DA0 So I would expect these glazes to be very safe.=3DA=
0 =3D
If
>> I am nit mistaken, these underglazes and glazes include mayco stroke
>> and coat reds and amaco velvet reds.=3DA0 Do these contain encapsulated
>> cadmium and hoe does the use of these glazes fit into this discussion?
>>
>> Any info is always appreciated.=3DA0 I am using my iPhone so please
>> excuse any autocorrections it decided to make that I did not catch.
>> Thx, Mary Jane
>>
>> Sent from my iPhone
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