Rachael Rice on tue 11 apr 00
I was wondering in my search for a food safe red that I could paint on
with my other commercial underglazes( mostly amaco velvets), can I make
an underglaze with red cerdec degusa stain. The red commercial
underglazes from Amaco and Duncan are not true reds. I read in the
archives about using cerdec red stains. I would be using it on
low-fire earthenware on greenware and then glaze with a clear commercial
low fire glaze on dinner plates in bisque. Do I need to get it tested
for cadmium leakage? Do they look like true reds in underglaze in low
fire? Thanks in advance for your thoughts.
Rachael
John Baymore on thu 13 apr 00
------------------
(clip)
I was wondering in my search for a food safe red that I could paint on
with my other commercial underglazes( mostly amaco velvets), can I make an
underglaze with red cerdec degusa stain. ............. low fire glaze on
dinner plates in bisque. Do I need to get it tested for cadmium leakage?
(snip)
Rachael,
Hi. Glad you are asking. The awareness of these types of issues is
certainly getting better.... in no small way due to the existence of
CLAYART and it's power in getting information around the potting community.
Federal law (and some states) is very specific about the standards for both
lead and cadmium use. It doesn't exempt handcraft potters....... we are
treated the same as any other manufacturers of claywares for food use. If
you are using Cd (or lead), you will have to have a specific testing
program in order to comply with the law. To comply, it isn't just testing
it one time and saying =22OK been there, done that=22. It requires a =
regular
program of sampling and testing.
BTW..... I don't use Amaco Velvets so I don't know how they are
made......... but you might check the cadmium (and lead) content of the
other underglazes you use....... such stuff shows up in surprising places
in commercial stuff.
The manufacturers do not indemnify the potter. It is your responsibility
(legal) to know your materials, protect the consumer, and comply with laws.
Best,
....................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JBaymore=40compuserve.com
John.Baymore=40GSD-CO.com
=22Earth, Water, and Fire Noborigama Woodfiring Workshop August 18-27,
2000=22
Smart on fri 14 apr 00
------------------
dear Rachael,
About Degussa Cerdec red stain (encapsulated cadmium oxide in zircon
crystal) you can use them in underglaze painting at hight fire (untill
1200=B0C). Hight resistance with temperature and chemical attacks is true. =
The
cadmium release is at very low level and usually in conformity with safe
regulations.
You can use ref : 17579 (true red), 17580 (carmin)
Cordialement,
Smart
Visit my French site : http://perso.wanadoo.fr/smart2000/
Sorry but only french speaking on this site. If you remember high school
learnings, it will be easy for you...
----- Original Message -----
From: Rachael Rice =3Crachaelrice=40erols.com=3E
To: =3CCLAYART=40LSV.UKY.EDU=3E
Sent: Tuesday, April 11, 2000 9:01 PM
Subject: Re: Using Cerdec Degusa Red stains in Underglaze
=3E ----------------------------Original message----------------------------
=3E
=3E
=3E
=3E
=3E
=3E I was wondering in my search for a food safe red that I could paint on
=3E with my other commercial underglazes( mostly amaco velvets), can I make
=3E
=3E an underglaze with red cerdec degusa stain. The red commercial
=3E underglazes from Amaco and Duncan are not true reds. I read in the
=3E archives about using cerdec red stains. I would be using it on
=3E low-fire earthenware on greenware and then glaze with a clear commercial
=3E
=3E low fire glaze on dinner plates in bisque. Do I need to get it tested
=3E for cadmium leakage? Do they look like true reds in underglaze in low
=3E fire? Thanks in advance for your thoughts.
=3E
=3E Rachael
Wade Blocker on fri 14 apr 00
----------
From: John Baymore
To: CLAYART@LSV.UKY.EDU
Subject: Using Cerdec Degusa Red stains in Underglaze
Date: Thursday, April 13, 2000 11:05 AM
----------------------------Original message----------------------------
------------------
(clip)
I was wondering in my search for a food safe red that I could paint on
with my other commercial underglazes( mostly amaco velvets), can I make an
underglaze with red cerdec degusa stain. ............. low fire glaze on
dinner plates in bisque. Do I need to get it tested for cadmium leakage?
(snip)
Rachael,
Hi. Glad you are asking. The awareness of these types of issues is
certainly getting better.... in no small way due to the existence of
CLAYART and it's power in getting information around the potting community.
Federal law (and some states) is very specific about the standards for both
lead and cadmium use. It doesn't exempt handcraft potters....... we are
treated the same as any other manufacturers of claywares for food use. If
you are using Cd (or lead), you will have to have a specific testing
program in order to comply with the law. To comply, it isn't just testing
it one time and saying "OK been there, done that". It requires a regular
program of sampling and testing.
BTW..... I don't use Amaco Velvets so I don't know how they are
made......... but you might check the cadmium (and lead) content of the
other underglazes you use....... such stuff shows up in surprising places
in commercial stuff.
The manufacturers do not indemnify the potter. It is your responsibility
(legal) to know your materials, protect the consumer, and comply with laws.
Best,
....................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JBaymore@compuserve.com
John.Baymore@GSD-CO.com
"Earth, Water, and Fire Noborigama Woodfiring Workshop August 18-27,
2000"
----------
The warning label accompaning the Amaco underglazes clearly states that to
be food save the underglazes have to be covered by a glaze.
Mia in ABQ
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