Tom Wirt on mon 2 aug 99
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----- Original Message -----
From: Richard Gralnik
To: claypot=40hutchtel.net
Sent: Friday, July 30, 1999 8:40 PM
Subject: Moonlight glaze
Anyway, regarding the glaze, Ron's recipe looks interesting. I've been on
clayart long enough to know to avoid Ghastly Borate if at all possible. =
But
I have a couple questions-
=3ECORN STN............ 27.00
=3EG 200 SPAR.......... 15.50 Can I swap for potash spar?
=3EGers Borate 9/97.... 4.00 A good year. Still available?
=3EF3134............... 13.00
=3EDOLOMITE............ 2.00
=3ESILICA.............. 12.00 Does the mesh matter?
=3EWHITING............. 6.50
=3EBELL DARK........... 20.00 ??? What is this???
=3EZINC OXIDE.......... 2.00 Doesn't this burn out at C6?
=3ERUTILE.............. 3.00 Does dark or light matter?
=3Eillmanite........... 2.00 Powdered or granular?
=3Ecobalt carb......... .30
=3E ----------
=3ETotal....................107.30
Richard (who wrote the above off-list) but it seems to fit on...
Yes you can swap G200 spar for Custer or other potash. Ron prefers the =
G-200
for being more consistent...for both glazes and clays. We've been running =
bag
tests (melting a small button of the spar) on every bag of Custer we use, =
and
every one looks a bit different.
Gerstley Borate....don't know if you can get it by the year. Ron had some=
of
this old stuff around....and it was a change in the gerstley that we think
started the crawling problems.
Silica mesh....it can make some difference in the melt...we usually use =
325
mesh. Others have said it makes no difference once it's melted.
Bell Dark is a ball clay from Ky-Tn Clays. We have substituted OM4 with =
only
minor changes in the results.
Zinc Oxide....yes it burns out in reduction and we've dropped it out, =
again
with no difference. If I was using this recipe in electric kilns (used to =
do
that and it comes out the same) I'd leave the zinc in.
Rutile. We've used both dark and light. The dark is better but may not =
be
available.
Powdered or granular....we use powdered for bout the Rutile and Illmenite.=
I
think the Rutile must be powdered, and granular Illmenite will give a =
different
flecking pattern...not as fine.
=3E=3E=3E=3Efrom Llwellyn
=3E=3E This glaze really intrigues me. I also don't have the Bell =
Dark ball
=3E=3Edidn't use the Darvan 7 and wonder what I am missing from getting =
good test
=3Eresults? I think I will hold off from mixing this one up in quantity =
since
=3Eit may well be that I am not seeing the 'best' results although I am on=
the
=3Etrail I may not have it yet and am in hot pursuit
Part of the crawling problem we were having was because of the use of =
Epsom
Salts and flocculating the glaze rather than defl=3Bocculating it. When you
flocculate it, you need more water to get a usable consistency. The =
Cornwall
and the gerstley both tend to swell up and thicken the glaze after mixing. =
When
you get too much water in a glaze, it will tend to crack as it dries. =
Sometimes
you will need a 8-10 power glass to see this cracking. The crawling starts =
in
these cracks, as there is a break in the clay/ glaze interface there.
=3EI also need to order the Darvan 7 as I do not have this and see other =
calls
=3Eand usage so should begin to stock.
We've started to use the Darvan (there are many other deflocculants out =
there)
in most of our glazes. You can get both dry and wet Darvan 7. The dry =
takes
forever to get liquefied (like wetting CMC gum only worse) so look for the =
wet
version. I know Continental Clay in Minneapolis carries it. =
(1-800-432-CLAY).
Also take a look in the archives and in Hamer/Hamer Dictionary re: =
discussions
on flocculation/deflocculation. Then hire Ron Roy to come by and show you =
how
it all works.
Hope this helps.
Tom Wirt/Betsy Price (La Glaziere)
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