Kate Johnson on sun 19 dec 04
Trying to understand what I'm dealing with here...I'm assuming, always a
dangerous thing to do, that not all frits are made with lead but it appears
that some are? Thinking of Earl Krueger's post of last Saturday, when he
was discussing the dangers of lead in frits...
ARE there safe frits to try? Is Frit 3110 lead free, specifically, since
that's what I bought? As my redware is intended to be functional, I'm still
working toward a lead-free honey/amber/golden transparent glaze appearance
of English and Colonial slip decorated redware...and still pushing that rock
uphill.
Dave Bracker or Good Earth Clays suggested I talk to Steve Branfman, which I
did--Steve was very helpful, and also suggested I talk to the glaze techs at
Amaco and two other companies--the weekend came, though, so waiting till
tomorrow. Will report back...
Thanks, yet again--
Kate Johnson, Luddite
Paul Lewing on sun 19 dec 04
on 12/19/04 8:55 AM, Kate Johnson at graphicart@EPSI.NET wrote:
> I'm assuming, always a
> dangerous thing to do, that not all frits are made with lead but it appears
> that some are?
That's true, Kate. Actually, very few frits have lead in them, but some do.
It's confusing because each frit formula has a different number, and each
frit company numbers their frits differently. Often different companies
make exactly the same formula, but the numbers will be different.
> ARE there safe frits to try? Is Frit 3110 lead free, specifically, since
> that's what I bought?
Frit 3110 is a Ferro frit, and all of Ferro's 3100 series are lead-free,
such as 3134, 3124, 3195, and so on. In Ferro's line, frits with numbers
beginning with 33, and some others, are leaded.
There are web sites and other resources that list frit formulas, one of
which is digitalfire.com.
Frit 3110 is probably a good starting point for you, as it's high in sodium,
a very powerful flux, and low in alumina, which raises the melting point. I
forget how much boron it has in it, but you may need some to get the
coefficient of expansion down low enough to prevent crazing. One of lead's
many advantages is its ability to fit a huge range of clay bodies. As I've
said before, for firing below about cone 1, lead is the perfect flux......
except for this one little nagging drawback.
Paul Lewing, Seattle
Daniel Semler on sun 19 dec 04
Hi Kate,
3110 is a leadless borosilicate frit. There's an analysis on
ceramicmaterials.info.
http://ceramic-materials.com/cermat/area.php?areaid=1&find=3110
There a lot of frits around, leaded and unleaded :) Manufacturers and suppliers
should be able to supply info. about the composition.
Thanx
D
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