Paul Lewing on sat 15 nov 97
Last night I went to an opening of wonderful new work by David Shaner
in Kirkland, WA, just across the lake from Seattle. Gorgeous stuff,
as usual. The man has been my hero for about 30 years now.
He's gotten away from the saturated manganese glaze he was using so
much of, and is developing a barium/copper green glaze. I told him
I'd been working on Ba/Cu greens for a while at ^5, using a Barium
frit, Ferro 3289. He was very interested till I told him that frit
carries as much Boron as it does Ba.
So my question for him (and me) is, can anyone tell me of any Barium
frits that do not contain Boron? It would be nice if they were
readily available in reasonable quantities for testing, say a pound or
two. I know there are many Ba frits out there, but 3289 is the only
one I have found an analysis for.
Thanks from both of us.
Paul Lewing
Craig Martell on sun 16 nov 97
Hi Paul:
Barium frits without boron are a bit hard to come by but there are a few
still available I think. I'll post the frit numbers and analyses below.
I think that most Ba frits are in combo with boron because of the strong
eutectic point that they have and maybe this is to provide a more active
source of Ba at lower temperatures. Most of the Ba/boron frits have a
fusion temp. somewhere between 1500-1700 degrees F. I used to use Ferro
Frit 3247 which was 53.1% barium in combo with Al and Si only, and had a
fusion temp of 1850F. Ferro stopped making it because it was very hard to
grind and was tearing up their ball mills as I recall. They subcontracted
the grinding to another company who eventually stopped producing the frit
for the same reason. I know what you're thinking. Why is this guy giving
me a history lesson, all I wanted were some Ba frits? Sorry, just leading
up to a point about why high Ba frits may not be available. They are
difficult to produce and therefore not generating a good profit margin for
Ferro of anyone else in production.
Ferro Frit 3831, K2O-12.0%, Na2O-4.6%, CaO-12.2%, BaO-17.9%, Al2O3-10.6%,
SiO2-42.7%, Coefficient of expansion(x10-6)-11.9, fusion temp.-1700F.,
molecular weight-186.3.
Pemco p-688, K2O-3.0, Na2O-1.6, CaO-15.8, MgO-4.3, BaO-10.6, ZnO-8.7,
Al2O3-7.0, SiO2-49.0, coefficient of expansion(x10-6)-8.0, Melting
point-1550-2100F.
The Ferro frit will probably work best as it's higher in Ba with fewer
additional oxides to worry about.
regards, Craig Martell-Oregon
Tony Hansen on mon 17 nov 97
> So my question for him (and me) is, can anyone tell me of any Barium
> frits that do not contain Boron?
Not sure if any of these are available but here are some:
Ferro 3247 53% BaO, 5.3 Al2O3, 41.6 SiO2
Ferro 3831 17 BaO, 12 CaO, 12 K2O, 4 Na2O, 10 Al2O3, 42 SiO2
Pemco P-404 (same formula as Ferro 3831)
Pemco P-688 10 BaO, 15 CaO, 3 K2O, 4 MgO, 1 Na2O, 9 ZnO, 7 Al2O3, 49
SiO2
--
-------
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Get INSIGHT, Magic of Fire at http://digitalfire.com
Cameron Harman on mon 17 nov 97
Paul Lewing,
In answer to your question about Boron in frits. Since we no
longer allow lead in frits, we need something that is
readily available, inexpensive and provides a good finish
that lowers the melt temperature. If you don't use lead in
low melting glazes you are pretty much stuck with Boron. At
higher melting temperatures it is a different story.
No big deal.
Cameron
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Mike Vatalaro on mon 17 nov 97
Paul,
This will appear odd but , I have been using a Brium Frit
from Ferro for the past five years or so, Frit Q257. I think I bought
50 pounds from ferro directly, And I can't tell why the unusual number
I use about 5 % in a cone five clear to affect the cobalt slip underneath.
Don't have the breackdown regarding boron ,you might check with Ferro .
If you do get it pass it on, I'm interested as well.
By the way Where do you get the Ferro3289 that you use ?
Thanks, Mike Vatalaro
Jeff Lawrence on tue 18 nov 97
Mike Vatalero was asking about sources for Ferro frit 3289.
All Laguna distributors are willing to order 3289 but I've found placing
the order directly with Laguna works better. You'll get the frit faster,
won't have to order as much and spend less. This frit has proven
indispensable in getting mature mat glazes at 04. An Insight printout of
3289 analysis I got from somewhere reliable (forget where, tho):
FERRO FRIT 3289..... 100.00 100.00%
========
100.00
BaO 0.83* 47.12%
Na2O 0.17* 3.82%
B2O3 0.38 9.67%
Al2O3 0.16 6.17%
SiO2 1.50 33.21%
Cost/kg 2.00
Si:Al 9.13
SiB:Al 11.43
Expan 9.41
Hope this helps.
Jeff
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