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glaze mixing error

updated tue 17 may 05

 

Steve Slatin on thu 5 may 05


Deb --

Borax is sold in some stores as a laundry detergent
(20 Mule Team Borax et. al.) -- also found in some
gardening places as a fungicide (I believe Sporax is
100% Borax, but I may not be recollecting accurately).
I used to get it as an insecticide also, small
containers -- 4 oz. or so -- at pharmacies -- it was
cheap 25-30 years ago. I don't know how much they are
now. So that should be no problem; there's different
sources.

Aluminum hydrate might be a little tougher -- some
kiln wash is, I believe, made from aluminum hydrate.
People who make enamel work with it, and your ceramics
supplier should have it. I don't know of any
generally available sources, though.

Best wishes, good luck reclaiming the glaze, and let
me know if I can help more. -- Steve S


--- claystuff wrote:
> Dear Steve,
> Your answer, very exacting and complicated, was
>

Steve Slatin --

Sera que ela mexe o chocalho ou o chocalho e que mexe com ela

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claystuff on thu 5 may 05


Hi everyone-=20
I made a major error in mixing up Hansen's 5 x20 Clear Glaze- =20
I added the Wollstonite, Frit 3134, Flint and Custer Feldspar ok. But I =
goofed and added Neph Sy instead of EPK. I realized it immediately when =
I went to add water. So now I have 5000 grams of this mix. =20
Can any glaze gurus with calculating software give me an idea of what to =
add to make this mix a glaze for Cone 6 or should I dump it and start =
again?=20

I do like to test glazes but I don't really know if all the elements of =
a glaze are in this bucket.

Thanks to all.
Debby

Mike Gordon on thu 5 may 05


Debbie,
If the glaze experts don't come up with a solution try this. Make a
small test tile and fire it as usual, keep it around and someday you
might find just the right use for it. Sculpture, texture,etc. Mike
Gordon
On May 5, 2005, at 9:46 AM, claystuff wrote:

> Hi everyone-
> I made a major error in mixing up Hansen's 5 x20 Clear Glaze-
> I added the Wollstonite, Frit 3134, Flint and Custer Feldspar ok. But
> I goofed and added Neph Sy instead of EPK. I realized it immediately
> when I went to add water. So now I have 5000 grams of this mix.
> Can any glaze gurus with calculating software give me an idea of what
> to add to make this mix a glaze for Cone 6 or should I dump it and
> start again?
>
> I do like to test glazes but I don't really know if all the elements
> of a glaze are in this bucket.
>
> Thanks to all.
> Debby
>
> _______________________________________________________________________
> _______
> Send postings to clayart@lsv.ceramics.org
>
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> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>

Steve Slatin on thu 5 may 05


hi --

This is just the sort of problem that a calc program
is good at helping with. It'd be easier if I knew
what other materials you had to work with, but let's
give it a quick look.

My calc program gives me (in molar concentration) this
for 5 x 20 vs. your mix --

Your Mix Regular Mix

Na2O 4.80 3.62
K2O 1.98 2.94
MgO 0.50 0.54
CaO 15.01 15.12

Alkali
subtotal 6.78 6.56

Total Flux 22.29 22.23

OK, so this shows us -- most importantly -- you're
really close on total fluxes. This means your mixture
will likely form a glaze; whether it'll be matte or
glossy, sticky or runny, etc. is still up in the air.

Also, you're high on the alkali's. This means that
although it's *some* kind of a possible glaze, it'll
probably have different color characteristics than
authentic 5 x 20 does.

Now, we look at other components --

Al2O3 5.27 9.72
B2O3 4.22 4.47
Fe2O3 0.05 0.11
Silica 68.18 63.40

Personally I don't think that as small a difference in
iron will do much, and the boron's off only a little.
(Worth correcting if we can, but not instantly
critical.) What's critical is the difference in
Alumina -- you've got barely half what the recipe
calls for. And you're high on silica -- enough so
that it will likely change glaze characteristics.

Calc software also provides some instant analysis --
two items worth noting are silica/alumina ratio and
LOI. LOI seems to be calculated differently in
different programs, so the numbers I have may be
nonsense to people with different programs, but the
relative LOI seems plausible --

Si/Al 12.94 6.52

LOI 1.21 3.46

Right away this means a good probability that it will
run like crazy, but with a nice LOI, you can do
different things to address that.

I also did a quick check of limit formulae -- another
thing that's quick and easy with software, and a
nuisance without -- and found that you come close to
fitting just about every model except you're high on
Alkalis for some models and low on Alumina for all.

If you have ground, calcined alumina available, that
would be the quickest way to bring your mix back into
balance. Add 8% (of the initial batch mix material
weight) and you'll have a Si/Al of 6.65, very close to
the target 6.52 and well within the range you'd hope
for with a good, reliable glaze. Calcined alumina has
a bad reputation for settling from glazes, and there
are handling issues, though. A quick fix if you need
it, but we can find better.

Another approach would be to add Alumina Hydrate,
roughly 13%. This does three things vs. plain
calcined alumina -- one, it raises your LOI to 5.07,
so you may get pinholing or other glaze defects. Two,
it suspends well. Three, it tends to make some glazes
(at least those with chrome as a colorant) go pink.
Maybe what you want, maybe not. Last, it's an
opacifier (because of the LOI, you end up with
microscopic bubbles suspended in the glaze.) Also,
because you're adding so much weight (and
corresponding number of molecules) you've now dropped
total fluxes to 21.208 -- certainly something to think
about, though you'll probably have a servicable glaze
here, neither matte nor runny, it may not be the
workhorse that 5 x 20 is.

Now remember, we're still willing to tinker with
sodium, potassium, and boron, and since we are going
to add other weight in, we need to adjust calcium,
too. I'm lazy so I take a shot at it by adding 2%
each of Frit 3134 and Wollastonite along with 10%
Alumina Hydrate (I reduced the amount here to bring
the rampaging LOI back under control) and 1% Borax,
which adds sodium as well as boron. (I can't control
the mix of boron just by adding 3134 because it's got
so much silica in it that it'll further mess up the
Si/Al ratio.)

This puts my total fluxes back at 22.237, or within a
whisker of the original. Alkalis are 6.67 instead of
6.56, but that's a tiny enough difference so it
probabaly won't be highly visible. (The mix of Na and
K is different, but my experience is that they're
largely interchangable.) Alumina is still low at 8.55
instead of 9.72, but you're in the range of a decent
glossy glaze and possibly not a runner. Your silica
is only 1 point high, and the Si/Al ratio is down to
7.53 (vs. target of 6.52). COE is 77.8 vs. 78.8, so
it probably wouldn't give you fit problems with your
standard clay unless 20 x 5 is already kind of at the
limit.

Now you say your an experimenter. At this point, you
likely have an experiment worth trying -- to your mix,
add (as a % of original total material weight) 2%
3134, 2% wollastonite, 10% alumina hydrate, 1% borax.
My guess is you're within range of a workable glaze
there, with LOI of 4.52 you may have a more opaque
glaze then you want, but possibly OK on pinholing.

I don't know what you have in your studio, but since
you certainly have Wolla and 3134, only the Al Hydrate
and Borax are iffy. And as a soluble (normally I stay
away from them) non-pro sources are equal in utility
to our near-industrial grade ceramic materials -- you
really do just add warm water and it melts on you. If
you do use this approach, add the stuff, mix it up and
glaze your pots pretty quickly thereafter. If you
wait for months before getting around to it, you will
almost certainly have problems because solubles don't
seem to operate consistently.*

One test tile will tell you if you're close. It's
cheaper (and environmentally sounder!) than tossing it
out.

Best wishes -- and if you have an available materials
list, I'll see if there's any easier approaches --

-- Steve Slatin

*(Unless you're Lee Love, in which case you prefer
solubles, measure your materials 'wet' in old boots
and coffee cans, and still have everything come out
well.)


--- claystuff wrote:
> Hi everyone-
> I made a major error in mixing up Hansen's 5 x20
> Clear Glaze-
> I added the Wollstonite, Frit 3134, Flint and Custer
> Feldspar ok. But I goofed and added Neph Sy instead
> of EPK. I realized it immediately when I went to
> add water. So now I have 5000 grams of this mix.
> Can any glaze gurus with calculating software give
> me an idea of what to add to make this mix a glaze
> for Cone 6 or should I dump it and start again?


Steve Slatin --

Sera que ela mexe o chocalho ou o chocalho e que mexe com ela



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claystuff on thu 5 may 05


Dear Steve,
Your answer, very exacting and complicated, was exactly what I was hoping
for from this list! I hope you enjoy doing the calculations! Thank you very
much.
Are you saying that I can find Borax and Al. Hydrate at my local
drugstore? I can pick them up this weekend and fire within a day or so.

I have other chemicals on hand although not a complete warehouse by any
means. I hope to follow your advice and I'll let you know the results.
Thanks again!!!
Deb

Daniel Semler on fri 6 may 05


Hi Steve,

I notice you're using mole % in these calcs rather than molecular unity form.
Do find some particular advantage to doing it this way, or is it just personal
preference ?

Thanx
D

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Steve Slatin on fri 6 may 05


Daniel --

It's mostly preference. Whatever you do first is
probably what you're comfortable with -- in my case, I
learned to do molar calcs in a chem class years back,
and when I read Clay and Glazes I saw normalizing to
the number 1 for fluxes as as an unnecessary
confusion.

Also, if you're firing to cone 6 instead of 10 or 12,
your fluxing action probably comes from boron and/or
zinc, and since the standard procedure puts one in as
flux and the other not, it can be a little tougher to
follow. Using molar or weight analysis eliminates
this confusion -- and as far as using weight, when you
sub two highly interchangable items, like potassium
for sodium, you change the weight without changing the
flux concentration and that can be a confusion.

I guess I've just talked myself into strong reasons
for preferring molar analysis there ...

-- Steve S.


--- Daniel Semler wrote:
> Hi Steve,
>
> I notice you're using mole % in these calcs rather
> than molecular unity form.
> Do find some particular advantage to doing it this
> way, or is it just personal
> preference ?
>
> Thanx
> D
>
>
----------------------------------------------------------------
> This message was sent using IMP, the Internet
> Messaging Program.
>
>
______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change
> your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be
> reached at melpots@pclink.com.
>


Steve Slatin --

Sera que ela mexe o chocalho ou o chocalho e que mexe com ela



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Ron Roy on sat 7 may 05


Hi Debby,

Mix this up and add it to the batch you have and it will be right again.

Wollas - 24.5
3134 - 24.5
EPK - 43.0
Silica - 29.5
Total - 121.5

Ratio is the same for this and the original 5x20
Calculated expansion for the original is 436.09 - and for the fixed glaze
is 433.38.

How do I know? The seger formula tells me so.

Anyone want to know how I did it? just let me know.

RR



>Hi everyone-
> I made a major error in mixing up Hansen's 5 x20 Clear Glaze-
>I added the Wollstonite, Frit 3134, Flint and Custer Feldspar ok. But I
>goofed and added Neph Sy instead of EPK. I realized it immediately when I
>went to add water. So now I have 5000 grams of this mix.
>Can any glaze gurus with calculating software give me an idea of what to
>add to make this mix a glaze for Cone 6 or should I dump it and start
>again?
>
> I do like to test glazes but I don't really know if all the elements of a
>glaze are in this bucket.
>
>Thanks to all.
>Debby

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513

Ron Roy on sun 8 may 05


Thanks Daniel,

RR


> Debby originally mixed 5000g. It took me a while to work out what was bugging
>me in your solution. All your numbers need to be multiplied by 50.
>Just adding the amounts below to her 5000g won't be enough.
>
>Thanx
>D
>
>> Hi Debby,
>>
>> Mix this up and add it to the batch you have and it will be right again.
>>
>> Wollas - 24.5
>> 3134 - 24.5
>> EPK - 43.0
>> Silica - 29.5
>> Total - 121.5
>>
>> Ratio is the same for this and the original 5x20
>> Calculated expansion for the original is 436.09 - and for the fixed glaze
>> is 433.38.
>>
>> How do I know? The seger formula tells me so.
>>
>> Anyone want to know how I did it? just let me know.
>>
>> RR
>>
>>
>>
>> >Hi everyone-
>> > I made a major error in mixing up Hansen's 5 x20 Clear Glaze-
>> >I added the Wollstonite, Frit 3134, Flint and Custer Feldspar ok. But I
>> >goofed and added Neph Sy instead of EPK. I realized it immediately when I
>> >went to add water. So now I have 5000 grams of this mix.
>> >Can any glaze gurus with calculating software give me an idea of what to
>> >add to make this mix a glaze for Cone 6 or should I dump it and start
>> >again?
>> >
>> > I do like to test glazes but I don't really know if all the elements of a
>> >glaze are in this bucket.
>> >
>> >Thanks to all.
>> >Debby

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513

claystuff on mon 16 may 05


Dear all,
An update on my glaze mixing error: (Trying to mix Hansens' 5 x 20 with =
the wrong ingredients)

I went with Ron' s quick fix (sorry Steve, but I had these ingredients =
already).

My original mix:
Wollastonite 20% 1000gr
Custer Feldspar 20% 1000
Neph Sye 20% 1000 (should have been EPK)
Silica 20% 1000
Frit 3134 20% 1000

Ron's fix:
Wollastonie 24.5% 1225
3134 24.5% 1225
EPK 43% 2150
Silica 29.5% 1475

New Totals- =20
Wollastonite 2225
Custer Feldspar 1000
Neph Sye 1000
Silica 2475
Frit 3134 2225
EPK 2150

Total 11075- a lot of glaze!

I just fired test tiles and the results are great! A nice glossy =
clear, no running! I also took a cup full of the clear and added a tiny =
bit of cobalt oxide and got a nice dark shiny blue. It will be hard to =
be exact with oxide additions as this is all mixed with water already.

Thanks to Ron and Steve for helping with this. Thanks to clayart!
Debby

Steve Slatin on mon 16 may 05


Debby --

Great news! 5 x 20 is a real sturdy base for lots of
different treatments, and I've had good luck using in
under other glazes as well.

And any time Ron and someone else make suggestions,
I'd recommend trying his way first. He's extremely
knowledgable and helpful.

-- Steve Slatin


--- claystuff wrote:
> Dear all,
> An update on my glaze mixing error: (Trying to mix
> Hansens' 5 x 20 with the wrong ingredients)
>
> I went with Ron' s quick fix

Steve Slatin --

Some men will do here for diamonds what some men will do here for gold



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