MJ on tue 5 apr 11
Thanks so much Ron and Robert - I will try the Epsom Salts later this week
and report back. Cheers, MJ
On Tue, Apr 5, 2011 at 1:44 PM, wrote:
> Hi MJ,
>
> Reduction in an electric kiln does not come from zinc but from organics
> that are still not burned out of bisqued clay or left over in the bricks
> themselves. Some clays have more organics in them than others but if you
> using a vent system you would not usually have a reduction problem. Zinc
> oxide is easily reduced to the metal which boils and can produce pin hole=
s.
>
> There is some Neph Sy in that glaze and that - combined with your local
> water is the reason your glaze is defloccing - the thinner the glaze is t=
he
> more likely that is to happen - adding bentonite can help but - what you
> need to do now is reflocculate the glaze.
>
> Get some Epsom salts and dissolve a couple of table spoons in a cup of
> water - microwaving and stirring works well - put it in a squirt bottle w=
ith
> a stopper - add a few drops to your glaze and stir well - let it rest for=
15
> minutes - stir again - if still settling add a couple more drops - stir -
> keep track of the number of drops so that when it happens again you will
> know approximately how many drops you need to add to the next batch.
>
> If your batch is really small (under 1000 grams) better only add one drop
> at a time.
>
> Let us know what happens - RR
>
>
> Quoting MJ :
>
> Hello - I mixed up a small batch of light stormy blue from the book
>> Mastering Cone 6 Glazes. The color came out great and the surface looks
>> great. The glaze itself seemed to settle almost immediately after
>> stirring. There was barely time to get the piece glazed without what I
>> would call severe settling. After a day, the settled glaze is very hard
>> and
>> it took quite a bit of effort to get it remixed. I wonder if anyone els=
e
>> has had this problem with this particular glaze or if it indicates that =
I
>> did something wrong in the mixing. If it is common for this glaze to
>> settle
>> so quickly, which ingredients in the glaze would be causing the problem.
>> I
>> made a second very small test batch adding 2 percent bentonite to see if
>> that solved the issue, but it did not. From reading previous posts, the
>> local water supply can make a difference.
>>
>> This glaze is zinc based. After rereding the information on page 98 of
>> the
>> MC6G book, I see a mention of local reduction when firing a zinc based
>> glaze
>> in oxidation. My kiln is vented. On this first firing of the glaze i d=
id
>> not experience pinholes (as was mentioned in some previous posts on this
>> glaze). If there is localized reduction occurring during the firing, is
>> it
>> affecting other pieces in the kiln that are not glazed with zinc based
>> glazes? If so, which glaze ingredients should I be most concerned with
>> having in the same firing?
>>
>> As always, any help is appreciated. Cheers, MJ
>>
>>
>
>
>
MJ on tue 5 apr 11
Hello - I mixed up a small batch of light stormy blue from the book
Mastering Cone 6 Glazes. The color came out great and the surface looks
great. The glaze itself seemed to settle almost immediately after
stirring. There was barely time to get the piece glazed without what I
would call severe settling. After a day, the settled glaze is very hard an=
d
it took quite a bit of effort to get it remixed. I wonder if anyone else
has had this problem with this particular glaze or if it indicates that I
did something wrong in the mixing. If it is common for this glaze to settl=
e
so quickly, which ingredients in the glaze would be causing the problem. I
made a second very small test batch adding 2 percent bentonite to see if
that solved the issue, but it did not. From reading previous posts, the
local water supply can make a difference.
This glaze is zinc based. After rereding the information on page 98 of the
MC6G book, I see a mention of local reduction when firing a zinc based glaz=
e
in oxidation. My kiln is vented. On this first firing of the glaze i did
not experience pinholes (as was mentioned in some previous posts on this
glaze). If there is localized reduction occurring during the firing, is it
affecting other pieces in the kiln that are not glazed with zinc based
glazes? If so, which glaze ingredients should I be most concerned with
having in the same firing?
As always, any help is appreciated. Cheers, MJ
Ron Roy on tue 5 apr 11
Hi MJ,
Reduction in an electric kiln does not come from zinc but from
organics that are still not burned out of bisqued clay or left over in
the bricks themselves. Some clays have more organics in them than
others but if you using a vent system you would not usually have a
reduction problem. Zinc oxide is easily reduced to the metal which
boils and can produce pin holes.
There is some Neph Sy in that glaze and that - combined with your
local water is the reason your glaze is defloccing - the thinner the
glaze is the more likely that is to happen - adding bentonite can help
but - what you need to do now is reflocculate the glaze.
Get some Epsom salts and dissolve a couple of table spoons in a cup of
water - microwaving and stirring works well - put it in a squirt
bottle with a stopper - add a few drops to your glaze and stir well -
let it rest for 15 minutes - stir again - if still settling add a
couple more drops - stir - keep track of the number of drops so that
when it happens again you will know approximately how many drops you
need to add to the next batch.
If your batch is really small (under 1000 grams) better only add one
drop at a time.
Let us know what happens - RR
Quoting MJ :
> Hello - I mixed up a small batch of light stormy blue from the book
> Mastering Cone 6 Glazes. The color came out great and the surface looks
> great. The glaze itself seemed to settle almost immediately after
> stirring. There was barely time to get the piece glazed without what I
> would call severe settling. After a day, the settled glaze is very hard =
and
> it took quite a bit of effort to get it remixed. I wonder if anyone else
> has had this problem with this particular glaze or if it indicates that I
> did something wrong in the mixing. If it is common for this glaze to set=
tle
> so quickly, which ingredients in the glaze would be causing the problem. =
I
> made a second very small test batch adding 2 percent bentonite to see if
> that solved the issue, but it did not. From reading previous posts, the
> local water supply can make a difference.
>
> This glaze is zinc based. After rereding the information on page 98 of t=
he
> MC6G book, I see a mention of local reduction when firing a zinc based gl=
aze
> in oxidation. My kiln is vented. On this first firing of the glaze i di=
d
> not experience pinholes (as was mentioned in some previous posts on this
> glaze). If there is localized reduction occurring during the firing, is =
it
> affecting other pieces in the kiln that are not glazed with zinc based
> glazes? If so, which glaze ingredients should I be most concerned with
> having in the same firing?
>
> As always, any help is appreciated. Cheers, MJ
>
Alice DeLisle on wed 6 apr 11
MJ,
From MJ: "I mixed up a small batch of light stormy blue from the book
Mastering Cone 6 Glazes. The color came out great and the surface looks gr=
eat.
The glaze itself seemed to settle almost immediately after stirring. Ther=
e was
barely time to get the piece glazed without what I would call severe settl=
ing.
After a day, the settled glaze is very hard and it took quite a bit of eff=
ort
to get it remixed."
I have been using Chun Clear glaze recently (cone 6 ox) and it is very simi=
lar
to this glaze. I had the same experience with it settling to concrete in t=
he
bottom of the bucket. It is from adding too much water. You have to use t=
his
glaze at a consistency that is very different from most other glazes. It s=
eems
very thick but that is how it works. When this happened to the Chun Clear =
that
I mixed, I added more dry ingredients and now it is fine. Maybe there are
others on the list who can give a good flocculation/deflocculation explanat=
ion
for this effect.
Here is the Chun Clear recipe for comparison:
F4 38
Whiting 14
Silica 30
Ball Clay OM4 6
Zinc 12
plus
Bentonite 2
Alice DeLisle
wanderland@att.net
http://www.etsy.com/shop/IslandTextures
MJ on sun 10 apr 11
Hello Ron and Robert* -* Today I tried the epsom salt solution and it
worked. It was a very small batch of glaze so it took hardly any of the
solution. Thanks again for the help. MJ
On Tue, Apr 5, 2011 at 7:04 PM, MJ wrote:
> Thanks so much Ron and Robert - I will try the Epsom Salts later this wee=
k
> and report back. Cheers, MJ
>
>
> On Tue, Apr 5, 2011 at 1:44 PM, wrote:
>
>> Hi MJ,
>>
>> Reduction in an electric kiln does not come from zinc but from organics
>> that are still not burned out of bisqued clay or left over in the bricks
>> themselves. Some clays have more organics in them than others but if you
>> using a vent system you would not usually have a reduction problem. Zinc
>> oxide is easily reduced to the metal which boils and can produce pin hol=
es.
>>
>> There is some Neph Sy in that glaze and that - combined with your local
>> water is the reason your glaze is defloccing - the thinner the glaze is =
the
>> more likely that is to happen - adding bentonite can help but - what you
>> need to do now is reflocculate the glaze.
>>
>> Get some Epsom salts and dissolve a couple of table spoons in a cup of
>> water - microwaving and stirring works well - put it in a squirt bottle =
with
>> a stopper - add a few drops to your glaze and stir well - let it rest fo=
r 15
>> minutes - stir again - if still settling add a couple more drops - stir =
-
>> keep track of the number of drops so that when it happens again you will
>> know approximately how many drops you need to add to the next batch.
>>
>> If your batch is really small (under 1000 grams) better only add one dro=
p
>> at a time.
>>
>> Let us know what happens - RR
>>
>>
>> Quoting MJ :
>>
>> Hello - I mixed up a small batch of light stormy blue from the book
>>> Mastering Cone 6 Glazes. The color came out great and the surface look=
s
>>> great. The glaze itself seemed to settle almost immediately after
>>> stirring. There was barely time to get the piece glazed without what I
>>> would call severe settling. After a day, the settled glaze is very har=
d
>>> and
>>> it took quite a bit of effort to get it remixed. I wonder if anyone el=
se
>>> has had this problem with this particular glaze or if it indicates that=
I
>>> did something wrong in the mixing. If it is common for this glaze to
>>> settle
>>> so quickly, which ingredients in the glaze would be causing the problem=
.
>>> I
>>> made a second very small test batch adding 2 percent bentonite to see i=
f
>>> that solved the issue, but it did not. From reading previous posts, th=
e
>>> local water supply can make a difference.
>>>
>>> This glaze is zinc based. After rereding the information on page 98 of
>>> the
>>> MC6G book, I see a mention of local reduction when firing a zinc based
>>> glaze
>>> in oxidation. My kiln is vented. On this first firing of the glaze i
>>> did
>>> not experience pinholes (as was mentioned in some previous posts on thi=
s
>>> glaze). If there is localized reduction occurring during the firing, i=
s
>>> it
>>> affecting other pieces in the kiln that are not glazed with zinc based
>>> glazes? If so, which glaze ingredients should I be most concerned with
>>> having in the same firing?
>>>
>>> As always, any help is appreciated. Cheers, MJ
>>>
>>>
>>
>>
>>
>
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