G. Fer on wed 2 jul 03
Hi there:
I live in the Dominican Republic (down in the caribean), here we don't
have fancy places to buy our materiales from. I work with clay (red), and
the only transparent glaze that they sell here is GLOSSY.
I have a problem with gloss, because even though i know i have to apply it
inorder to get the reaction from the oxides i use (cobalt, iron, cooper,
etc), is there something that i an add to this TRANSAPARENT GLOSSY GLAZE, in
order to make it a opaque (matte), or at least lower it down?
Also, they don't sell frits here either, is there an element that i can buy
from a chemical lab that can subtitue as a frit, so that i can ue it as a
base when i mix my glazes?
Thank you very much for your help and i will be awaiting your advice
Sincerly
Gustavo Fermin
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Antoinette Badenhorst on thu 3 jul 03
Dear Gustavo, you have a million challenges! By adding some silica to
your glaze you can change it to become more matt, but if the glaze is
already high in silica, it may change your firing temp. You can also add
some clay(alumina)Start out with small amounts ,maybe 5%. Here is a
possible solution that might change what you are doing, but might give
interesting effects. Mix up a terra sigilata with sodium silicate and
cover your pots with that. (Recipes on clay art) See what happens if you
glaze over that. You can add oxides to your ts to obtain other colors(if
you mix a white ts).
Antoinette Badenhorst
105 Westwood Circle
Saltillo MS
38866
662 869 1651
www.calyandcanvas.com
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of G. Fer
Sent: Wednesday, July 02, 2003 5:56 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Problem with Glossy Transparent Glaze
Hi there:
I live in the Dominican Republic (down in the caribean), here we
don't
have fancy places to buy our materiales from. I work with clay (red),
and
the only transparent glaze that they sell here is GLOSSY.
I have a problem with gloss, because even though i know i have to apply
it
inorder to get the reaction from the oxides i use (cobalt, iron, cooper,
etc), is there something that i an add to this TRANSAPARENT GLOSSY
GLAZE, in
order to make it a opaque (matte), or at least lower it down?
Also, they don't sell frits here either, is there an element that i can
buy
from a chemical lab that can subtitue as a frit, so that i can ue it as
a
base when i mix my glazes?
Thank you very much for your help and i will be awaiting your advice
Sincerly
Gustavo Fermin
_________________________________________________________________
Protect your PC - get McAfee.com VirusScan Online
http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
________________________________________________________________________
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piedpotterhamelin@COMCAST.NET on thu 3 jul 03
Additions of calcium such as whiting or plaster, strontium, flint will also
increase the matt. Maybe magnesium can help, such as in Epsom salt but I never
have tried that root. Matting is either due to increasing the melting point of
the glaze or allowing the forming of crystals in the glaze.
> Hi there:
>
> I live in the Dominican Republic (down in the caribean), here we don't
> have fancy places to buy our materiales from. I work with clay (red), and
> the only transparent glaze that they sell here is GLOSSY.
> I have a problem with gloss, because even though i know i have to apply it
> inorder to get the reaction from the oxides i use (cobalt, iron, cooper,
> etc), is there something that i an add to this TRANSAPARENT GLOSSY GLAZE, in
> order to make it a opaque (matte), or at least lower it down?
>
> Also, they don't sell frits here either, is there an element that i can buy
> from a chemical lab that can subtitue as a frit, so that i can ue it as a
> base when i mix my glazes?
>
> Thank you very much for your help and i will be awaiting your advice
>
> Sincerly
>
> Gustavo Fermin
>
> _________________________________________________________________
> Protect your PC - get McAfee.com VirusScan Online
> http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
piedpotterhamelin@COMCAST.NET on thu 3 jul 03
The first question is are you making functional pottery or decorative items?
If you are making decorative, you could experiment by adding some clay to
your glaze to matt the glaze. Otherwise, experiment with screened soils and
pulverized rock as an additive. I remember years ago, that a book was written
of using pharmacy purchased chemicals, zinc oxide, pepto bismol, etc as glaze
ingrediants. Find out your local soil types and experiment.
If functional, contact a frit manufacturer. You can find ferro, fusion
ceramics, general frit. Maybe you find a cheap way to get the frit to you.
Such as piggy backing your order onto a larger shipment to an industrial
customer who uses it to manufacturer grinding wheels etc. You should keep your
glaze safe and durable.
Good luck
My nephew and his wife are honeymooning in your country as we speak
Rick
> Hi there:
>
> I live in the Dominican Republic (down in the caribean), here we don't
> have fancy places to buy our materiales from. I work with clay (red), and
> the only transparent glaze that they sell here is GLOSSY.
> I have a problem with gloss, because even though i know i have to apply it
> inorder to get the reaction from the oxides i use (cobalt, iron, cooper,
> etc), is there something that i an add to this TRANSAPARENT GLOSSY GLAZE, in
> order to make it a opaque (matte), or at least lower it down?
>
> Also, they don't sell frits here either, is there an element that i can buy
> from a chemical lab that can subtitue as a frit, so that i can ue it as a
> base when i mix my glazes?
>
> Thank you very much for your help and i will be awaiting your advice
>
> Sincerly
>
> Gustavo Fermin
>
> _________________________________________________________________
> Protect your PC - get McAfee.com VirusScan Online
> http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Snail Scott on thu 3 jul 03
At 10:56 PM 7/2/03 +0000, you wrote:
>...is there something that i an add to this TRANSAPARENT GLOSSY GLAZE, in
>order to make it a opaque (matte)...
I'd try magnesium carbonate, and/or a nice, slow
cool. Many otherwise glossy glazes will turn
slightly matte if cooled slowly enough. 'Firing
down' by turning the kiln lower, but not off,
for a while after reaching temperature, may be
necessary if you have a lighly insulated kiln.
Magnesium will alter the color of your blues,
but can be sourced form magnesium carbonate,
dolomite, or other sources. It causes microcrystal
growth, which is one cause of matteness in glazes.
(The other main cause of matte glazes is under-
firing.)
-Snail
Paul Lewing on thu 3 jul 03
on 7/2/03 2:56 PM, G. Fer at wh0is@HOTMAIL.COM wrote:
> I live in the Dominican Republic (down in the caribean), here we don't
> have fancy places to buy our materiales from. I work with clay (red), and
> the only transparent glaze that they sell here is GLOSSY.
> I have a problem with gloss, because even though i know i have to apply it
> inorder to get the reaction from the oxides i use (cobalt, iron, cooper,
> etc), is there something that i an add to this TRANSAPARENT GLOSSY GLAZE, in
> order to make it a opaque (matte), or at least lower it down?
I'm going to assume you're firing to low-fire temperatures (cone 06-04)
because you say you're using red clay. I'm also going to assume when you
say "lower it down" that you mean lower the level of gloss, not the firing
temperature.
One thing you might try is adding some of your clay to the glaze. Since
your clay has iron in it, the glaze will not come out as clear, but it
doesn't sound like that would be a problem for you. If you can get your
hands on some white clay, you could add that to lower the gloss without
losing transparency.
And if you are working at low-fire temperatures, you might try adding some
magnesia, which at high temperatures is a flux, but at low-fire is just the
opposite. See if you can find a source of talcum powder, which is talc
(magnesium silicate), or powdered limestone (about equal parts MgO and CaO).
Look for powdered lime at garden supply stores. The soil in tropical
climates tends to be pretty acid, so gardeners may be adding lime to sweeten
their soil. Or go to your local sports stadium. We all know how popular
baseball is in the Dominican, and I'll bet you have a local soccer field
too. They may be using powdered lime to make lines on the field.
Good luck,
Paul Lewing, Seattle
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