Anne Webb on sun 30 sep 07
I mixed a new batch of a ^10 white glaze I use and used "zircopax plus" as =
the opacifier. This particular glaze is one that is my steadfast happy gla=
ze that always seems to look great and stays put no matter how hot the kiln=
gets.=20
WELL! This past week I had a most unfortunate gas firing and the glaze w=
as not opacified at all, but rather flowed like a son of a .. gun. I knew i=
t wasn't overfired since my other glazes which can run, stayed nicely put. =
=
=20
Usually use superpax without a prob. Always under the assumption that zirco=
pax and superpax were the same thing. Perhaps zircopax PLUS is different..=
.? I havent contacted anyone about it yet.
=20
All I know is I lost half a kiln load, missed out on a show, and have some=
serious shelf grinding to do. Any thoughts? =20
=20
Thanks! Anne
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Tom at Hutchtel.net on sun 30 sep 07
Subject: Re: Zircopax Plus
> Anne,
> To add to what Hank Murrow said, there is
> a way to prevent errors during glaze batching.
> I prepared a typed list of every component.
> example: accumulated
> item weight total wt
> bucket 2.2 2.2
> water 30.0 32.2
> feldspar 8.8 41.0
> calcium carbonate 6.6 46.6
> silica 4.4 51.0
> clay 2.2 53.2
>
>>From this you can tell immediately if an
> ingredient was added or not. Keep a l
I use the accumulated method for test batches. For regular batches, (20,000
gms-10 gal) we calculate the number of buckets of ingredient needed ( our
scale has a max of 2000 gms per bucket so 7850 gms would be 3 buckets (6000
gms) plus 1850 gms. On the bas of the scale I drilled a series of 5 holes,
2 rows. If I need 3 buckets plus the odd amount, I move 3 pegs up to the
top row. As I put in each bucket of material, on peg gets moved down. when
all 3 are down, I know to add the odd amount and check off that material as
done.
.
As in Michaels, this way, even if you get interrupted, you know where you
were. Mixing glaze doesn't seem like a big deal, and it isn't, if you pay
attention. But, without a system of some sort, even a simple phone call can
wreck a batch.
Tom Wirt
Hutchinson, MN
twirt@hutchtel.net
www.claycoyote.com
Hank Murrow on sun 30 sep 07
On Sep 29, 2007, at 11:15 PM, Anne Webb wrote:
> I mixed a new batch of a ^10 white glaze I use and used "zircopax
> plus" as the opacifier. This particular glaze is one that is my
> steadfast happy glaze that always seems to look great and stays put
> no matter how hot the kiln gets.
> WELL! This past week I had a most unfortunate gas firing and the
> glaze was not opacified at all, but rather flowed like a son of
> a .. gun. I knew it wasn't overfired since my other glazes which
> can run, stayed nicely put.
> Usually use superpax without a prob. Always under the assumption
> that zircopax and superpax were the same thing. Perhaps zircopax
> PLUS is different...? I havent contacted anyone about it yet.
>
> All I know is I lost half a kiln load, missed out on a show, and
> have some serious shelf grinding to do. Any thoughts?
Dear Anne;
Something like this has happened to me before. I mixed up a new batch
and had to sub a material, only to find that the glaze misbehaved. We
focus on the thing that has changed(superpax) rather than the fact
that we mixed up a new batch. I am betting that the new batch had a
mistake in the mixing. the way to test my theory would be to
carefully mix another smaller batch using the zircopax and see if it
behaves normally. BTW, I looked up Zircopax Plus to find that it is
the same as Superpax(changed the name but not the material).
Cheers, Hank
www.murrow.biz/hank
Michael Wendt on sun 30 sep 07
Anne,
To add to what Hank Murrow said, there is
a way to prevent errors during glaze batching.
I prepared a typed list of every component.
example: accumulated
item weight total wt
bucket 2.2 2.2
water 30.0 32.2
feldspar 8.8 41.0
calcium carbonate 6.6 46.6
silica 4.4 51.0
clay 2.2 53.2
From this you can tell immediately if an
ingredient was added or not. Keep a lid
handy so that if you are interrupted you
can cover the batch and not lose weight
to confuse the method.
As an added precaution, we place the bags
of ingredients in a row in the order they are
added and once added, the bag is put away
(or moved if to be used again) so we are
sure there are no omissions or double additions.
The running glaze you described can come from
too much of a low melting point flux like Frit
or Gerstley Borate so great care is needed
when using these to avoid mistakes.
Good Luck,
total
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
Lee Love on sun 30 sep 07
I put a box next to each item. Before I get the next material, I make
a diagonal line in the box. After I put the material in the batch
bucket, I make another diagonal, completing an "X"
--
Lee in Minneapolis, Minnesota USA
"We are not afraid to entrust the American people with unpleasant
facts, foreign ideas, alien philosophies, and competitive values. For
a nation that is afraid to let its people judge the truth and
falsehood in an open market is a nation that is afraid of its people."
--JFK
=?iso-8859-1?Q?Tig_Dupr=E9?= on mon 1 oct 07
-----------------------------<-------------------------------
WELL! This past week I had a most unfortunate gas firing and the glaze=20
was not opacified at all, but rather flowed like a son of a .. gun. I knew=
=20
it wasn't overfired since my other glazes which can run, stayed nicely put.=
=20
=20
Usually use superpax without a prob. Always under the assumption that=20
zircopax and superpax were the same thing. Perhaps zircopax PLUS is=20
different...? I haven't contacted anyone about it yet.--------------------=
---------<-------------------------------
=20
Anne,
=20
I haven't used zircopax plus, and do not really know the difference. My su=
spicion is that somehow, your ingredients got mixed up. Perhaps your wareh=
ouse technician at the local store got distracted and put the wrong ingredi=
ent in the zircopax bag. It's been known to happen. I won't say where, bu=
t I had a worker at one store tell me, "What are you so upset about? One w=
hite powder is about the same as another, right?"
=20
Can you compare the new product with some of the old?
=20
I'm sorry for the loss, and I empathize with the kiln shelf grinding. Been=
there... :o(
=20
Best of luck,
=20
Tig Dupre
in gray, wet Port Orchard, Washington
=
Anne Webb on tue 2 oct 07
Hey Tig..
You made my day:
"I won't say where, but I had a worker at one store tell me, "What are
you so upset about? One white powder is about the same as another,
right?""
..unbelievable!
A few years ago we had just about the same problem with a bag of non-opacif=
ying "zirconium opacifier", except without the total meltdown because I thi=
nk the kiln was slightly cooler and the glaze not as thick. Brand new 50 lb=
bag of the stuff. Mixed and remixed the glaze, and then tested against the=
little bit of old opacifier that we had. The culprit was the new stuff. G=
ot a new bag of opacifier (different company) and the problem was gone. =20
This spring I did a major shovelling out and reorganization of the studio. =
The glaze ingredients all have their own room now. When transferring the i=
ngredients over, I noticed that we had 2 50 lb bags of zirconium opacifier.=
Apparently the old bag that didn't work a few yrs ago had not, in fact, be=
en disposed of or marked that it was no good. I guess that's what one gets=
1. for leaving something to memory, and 2. leaving something to someone el=
se to do.
ANYhow.. the stuff out of this last firing looked very much like that from =
the bad firing from 2 or 3 yrs ago. =20
I am at this point assuming that the ingredients from the "bad bag" was us=
ed this time around as well, but will be testing both just to be sure, as =
well as remixing the white glaze to ensure it wasnt a mixing error. Thanks=
, I will visually compare the two opacifiers in their raw state again.
...and THIS time, I will contact the company, which i didn't do 2 yrs ago.=
=20
Will keep you posted. Thanks to you and everyone else who responded to my p=
ost.
Anne
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