Tom Wirt on fri 15 oct 99
Subject: Granular Strontium
> ----------------------------Original message----------------------------
>
> We just got a bag of Strontium Carbonate and it was the kind of
crystalline
> version. This acts differently in the glaze we use it in.....giving a
much
> darker and browner coloring. Seems l;ast time we went through this, the
> milled/powdered strontium later showed up in a 100 or so lb. barrel.
Answering my own question...Betsy talked to one of the people at Barium and
Chemicals, Inc. in Stuebenville OH, where Continental Clay gets their
Strontium Carb.
He said they carry 2 grades of SC....technical and a high purity. The
technical is generally about 92% SC with a wide spec for processing particle
size. It's primarily used by industry where it is further processed and/or
refined. The high purity stuff is 99% SC and very expensive. For a very
few cents extra per pound they will mill to 200 mesh if requested. The
buyer is expected to know this. Otherwise the furnished product will be
somewhere within the broad spec.
So, if you're using one type of SC, large particle or 200 mesh, best to test
before changing. If the strontium is a large percent of the recipe, the
loss on thee screen as well as the larger particle size can make a
difference in glaze performance.
Betsy was also advised to dissolve the stuff in hot water by Mile High
Ceramics...Denver. Doesn't work. It only partially dissolved to go through
an 80 mesh screen after sitting all night on a hot kiln. The 1999 materials
handbook states that it is "soluble in acids and slightly soluble in
water...especially if carbonated. It starts to decompose to the oxide at 800
degC in air. It is made in North America, mostly by processing celesite
(SrSO4) either by boiling in a solution of ammonium or sodium carbonate, or
by fusion with sodium carbonate."
The glaze we're using it in is Chappel's "EarthBrown, Cone 10"
James Chappel
Earth Brown Satin Matt C10
Custer Spar 32
Dolomite 22
Strontium Carbonate 15.75
EPK 15
Silica 9
Red Iron Oxide 4.5
Rutile 1.0
Bentonite 1.0
This recipe was adapted from the original Barium glaze using the .75:1
conversion ratio.
Tom Wirt
Clay Coyote Pottery
17614 240th St.
Hutchinson, MN 55350
320-587-2599 fax 320-234-6849
claypot@hutchtel.net
Edouard Bastarache on fri 15 oct 99
------------------
Hello all,
maybe leaving granular strontium carbonate more than overnight
with the rest of the ingredients would be a good idea.
I had some granular lithium carbonate and greatly improved this
=22granule=22 situation by letting to whole glaze soak for 1 week before
doing the final sieving and using it.
Later,
Edouard Bastarache
edouardb=40sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/=7Eedouardb/
-----Message d'origine-----
De : Tom Wirt =3Cclaypot=40hutchtel.net=3E
=C0 : CLAYART=40LSV.UKY.EDU =3CCLAYART=40LSV.UKY.EDU=3E
Date : 15 octobre, 1999 09:19
Objet : Re: Granular Strontium, Some answers
=3E----------------------------Original message----------------------------
=3ESubject: Granular Strontium
=3E
=3E
=3E=3E ----------------------------Original =
message----------------------------
=3E=3E
=3E=3E We just got a bag of Strontium Carbonate and it was the kind of
=3Ecrystalline
=3E=3E version. This acts differently in the glaze we use it in.....giving =
a
=3Emuch
=3E=3E darker and browner coloring. Seems l=3Bast time we went through this,=
the
=3E=3E milled/powdered strontium later showed up in a 100 or so lb. barrel.
=3E
=3EAnswering my own question...Betsy talked to one of the people at Barium =
and
=3EChemicals, Inc. in Stuebenville OH, where Continental Clay gets their
=3EStrontium Carb.
=3EHe said they carry 2 grades of SC....technical and a high purity. The
=3Etechnical is generally about 92=25 SC with a wide spec for processing
particle
=3Esize. It's primarily used by industry where it is further processed =
and/or
=3Erefined. The high purity stuff is 99=25 SC and very expensive. For a =
very
=3Efew cents extra per pound they will mill to 200 mesh if requested. The
=3Ebuyer is expected to know this. Otherwise the furnished product will be
=3Esomewhere within the broad spec.
=3E
=3ESo, if you're using one type of SC, large particle or 200 mesh, best to
test
=3Ebefore changing. If the strontium is a large percent of the recipe, the
=3Eloss on thee screen as well as the larger particle size can make a
=3Edifference in glaze performance.
=3E
=3EBetsy was also advised to dissolve the stuff in hot water by Mile High
=3ECeramics...Denver. Doesn't work. It only partially dissolved to go
through
=3Ean 80 mesh screen after sitting all night on a hot kiln. The 1999
materials
=3Ehandbook states that it is =22soluble in acids and slightly soluble in
=3Ewater...especially if carbonated. It starts to decompose to the oxide at
800
=3EdegC in air. It is made in North America, mostly by processing celesite
=3E(SrSO4) either by boiling in a solution of ammonium or sodium carbonate, =
or
=3Eby fusion with sodium carbonate.=22
=3E
=3EThe glaze we're using it in is Chappel's =22EarthBrown, Cone 10=22
=3E
=3E
=3EJames Chappel
=3EEarth Brown Satin Matt C10
=3E
=3ECuster Spar 32
=3EDolomite 22
=3EStrontium Carbonate 15.75
=3EEPK 15
=3ESilica 9
=3E
=3ERed Iron Oxide 4.5
=3ERutile 1.0
=3EBentonite 1.0
=3E
=3E
=3EThis recipe was adapted from the original Barium glaze using the .75:1
=3Econversion ratio.
=3E
=3ETom Wirt
=3EClay Coyote Pottery
=3E17614 240th St.
=3EHutchinson, MN 55350
=3E320-587-2599 fax 320-234-6849
=3Eclaypot=40hutchtel.net
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