Helen Bates on wed 18 jun 08
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Another "Compilation" from New Clay on Yahoo Groups:=20
Subject: Frit 3249? Sub needed... =20
#76 From: John Goode
Date: Tue May 20, 2008 1:25 pm
Subject: Frit 3249? Sub needed... =20
Hi Folks
I am doing a low expansion glaze to cone 6 and it
calls for a low expansion frit( 3249 )... My usual
supplier does not have. Does any one know of a
substitute? Thanks Johnny
#77 From: "Helen Bates"
Date: Tue May 20, 2008 4:37 pm
Subject: Re: Frit 3249? Sub needed... =20
Hi John,
I thought I'd see what I could "google" about this (no actual
experiences with glaze-making, though.)
One resource I found is Tony Hansen's Ceramic Materials Com education
site: http://ceramic-materials.com/cermat/education/121.html
He writes: "... It turns out that substituting MgO for other fluxes
is by far the most effective way to reduce glaze thermal expansion.
Fusion frit F69 or Ferro 3249 are the magic behind this type of
approach (Frit 3249 contains a little CaO in addition to the MgO).
These high magnesia frits melt much better than any natural MgO source
and they do not produce gases during decomposition."
So, there is a Fusion frit F69 that is similar to Ferro 3249 in its
ability to reduce thermal expansion in a glaze, but the fact that it
doesn't have any CaO in it would need to be calculated for...
See:
http://ceramic-materials.com/cermat/material/369.html
http://ceramic-materials.com/cermat/material/547.html
Also, Ceramics Today has a frit substitution chart online:
http://www.ceramicstoday.com/frits.htm.
It shows Pemco P-1409 as an equivalent for Ferro 3249
This chart is also available at Laguna's site (as a PDF):
http://www.lagunaclay.com/catalog/pdf/lcc_frit.pdf
The best comparison charts so far are at the Big Ceramic Store site:
http://www.bigceramicstore.com/Information/frit_comparisons.htm
FERRO 3249, GENERAL GF-144, PEMCO MOBAY BAYER P-1409, and FUSION F-69
are listed as equivalent.
By the way...
Tom or Nick's Ceramics & Pottery lists Ferro 3249:
http://www.tomornicksceramics.com/RawMaterials.html
Tom or Nick's Ceramics & Pottery, 1482 Dewey Avenue, Rochester, NY
14615, Phone: (585) 254-0640, FAX: (585) 254-0644
and... Ceramic Supply seems to be selling Ferro 3249:
http://www.7ceramic.com/Merchant2/merchant.mvc?Screen=3DCTGY&Category_Cod=
e=3DCHEM_10\
0
So does Axner:
http://www.axner.com/axner/materials/raw-materials.php
British Low Expansion Frits:
Potclays
low expansion leadless frits:
2203
http://www.potclays.co.uk/OrderProduct_144.asp
2279
http://www.potclays.co.uk/OrderProduct_173.asp
Technical Data for Potclays frit 2279:
http://www.potclays.co.uk/Newsletters/downloads%5CTechnical%20Data%5CFRIT=
%20FORM\
ULAE.doc
(MS DOC file)
Potclays Frit 2279
(Seger?) Formula:
0.176 Li2O
0.324 CaO 0.400 Al2O3 5.290 SiO2
0.173 ZnO 1.280 B2O3
0.252 MgO
% ANALYSIS: Li2O 0.10, CaO 3.60, ZnO 3.30, MgO 2.40, Al2O3 8.20, SiO2
63.60, B2O3 17.80
(However, no formula or % analysis is given for Potclays Frit 2203)
Potterycraft:
low Expansion leadless frits:
http://www.potterycrafts.co.uk/extra%20content/generic.asp?GroupID=3D22&b=
annerId=3D2\
29§ion=3Df&file=3D../extra%20content/frits.html
P2957:
Coeff: 5.9; Firing range (=B0C): 1000-1100; % Analysis : SiO2 62.0,
B2O3 14.8, MgO 0.2, Al2O3 9.4, Na2O 3.6, K2O 2.7, CaO 7.3
P2960:
Coeff: 3.8; Firing range (=B0C): 1020-1150; % Analysis: SiO2 63.4,
B2O3 17.6, MgO 2.2, Al2O3 8.5, K2O 0.2, CaO 3.7, Li2O 1.1, ZnO 3.2
Helen
PS: Having done my best with a lot of "cut and paste" work, I
apologise in advance for any errors...
--
Helen Bates
Belleville, Ontario, Canada
Clayarters' URLs: http://amsterlaw.com/clayart/
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