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making glazes

updated thu 24 nov 11

 

tammy brown on wed 5 may 04


Ah Bob
that is also an option
I think I will try the reticent teacher ( tongue in
cheek) route and see what I can do with engobes...
I am mostly quite pleased with my slip projects...but
after dipping in the white glaze I am perplexed...lots
to learn...to determine that finish which I am
striving to meet...
Thanks for your advice
Tammy






--- Bobbruch1@AOL.COM wrote:
> Tammy writes:
> >...what should I put over the bisque
> >firing to make the piece look finished without
> >obscuring my original slip colors and adding no
> >sheen?
>
> I haven't tried this with engobes, but I have
> asked the same questions about underglazes ....
> along with the issue of adherence, which may
> not be the same problem with engobes as it
> can be with velvet underglazes .....
> one solution I found was to test adding minute
> amounts of a clear transparent glaze that works
> on your clay body to velvet underglazes
> to find a point where it adheres well to the
> clay body, has a more finished look, and still does
> not create sheen. There are other ways to create
> a melt with an engobe, and I suppose you just
> need to do a line blend to see what you feel
> is appropriate.
>
> Bob Bruch
>
>
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tammy brown on wed 5 may 04


Ahhh Snail
I just spent a long time responding to your email and
I think I lost the response I was intending....oh
reticent teacher ( tongue in cheek of course) I think
your suggestions yesterday might be a good route for
me to venture. If I ever get this studio together and
of couse LL( if I did not have to work the "other
job") I might well endeavour upon the secret to your
knowledge.... practice....testing...I have tested
quite a lot with my slip colors and I find that I get
better each time I do this...and I get the results
more precies as I move along....
Funny I will finish a piece and I think it is pretty
good until I do another and after I finish that second
piece I realize that it is better than the one
before...so I figure like this.... If I keep going I
will achieve the results I am looking for...
are you sure Snail...sure .. .that you as a =sculpture
artist cannot even recommend a basic glaze with which
you started? or one that may tweak to my own likes??/
you are moving your studio but you are not moving your
knowledge? and I cannot imagine that someone with your
knowledge does not know a recipe off the top of your
head? HAHA
I will search the archives...I simply want to start
with a basic knowledge and experiment my brains
out...but I also realize that I needed to buy this
kiln....and learn to fire my own...
Everyone has a different vision and different
tastes...
Whew I am exhausted after that tirade...
I liked our firing advice too...
thanks Snail..
Tammy






--- Snail Scott wrote:
> At 08:39 AM 5/5/04 EDT, Bob B wrote:
> >I haven't tried this with engobes, but I have
> >asked the same questions about underglazes ...
>
>
> Remember, underglazes ARE engobes! Did you
> mean 'commerically-manufactured underglazes'?
> (...and the pedant rears its ugly head...) ;)
>
>
> >one solution I found was to test adding minute
> >amounts of a clear transparent glaze that works
> >on your clay body to velvet underglazes...
>
>
> This is a very handy shortcut. It's nice to
> develop your own, but if a commercial product
> is close to what you are after, and reliance
> on that source of supply isn't an issue, it's a
> great convenience. I did this often (with other
> products - I don't like the Velvets) when I
> lived near a supplier, and specially when worked
> for one. Now, it's hours of driving through Donner
> Pass just to buy a jar of commercial underglaze,
> so it's become easier for me to work from scratch.
>
> It's sort of a variation on the seat-of-the-pants
> 'take a clay body, and add flux, calcined clay,
> and colorants to suit' method.
>
> 'From scratch' is not an inherent moral virtue. ;)
> It's a means to an end, and so is the use of
> commercial products. Each has its advantages and
> drawbacks. Everbody gets to pick their preference.
>
>
> -Snail Scott
> Reno, Nevada, USA, Earth
>
>
______________________________________________________________________________
> 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.





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Bobbruch1@AOL.COM on wed 5 may 04


Tammy writes:
>...what should I put over the bisque
>firing to make the piece look finished without
>obscuring my original slip colors and adding no
>sheen?

I haven't tried this with engobes, but I have
asked the same questions about underglazes ....
along with the issue of adherence, which may
not be the same problem with engobes as it
can be with velvet underglazes .....
one solution I found was to test adding minute
amounts of a clear transparent glaze that works
on your clay body to velvet underglazes
to find a point where it adheres well to the
clay body, has a more finished look, and still does
not create sheen. There are other ways to create
a melt with an engobe, and I suppose you just
need to do a line blend to see what you feel
is appropriate.

Bob Bruch

Snail Scott on wed 5 may 04


At 08:39 AM 5/5/04 EDT, Bob B wrote:
>I haven't tried this with engobes, but I have
>asked the same questions about underglazes ...


Remember, underglazes ARE engobes! Did you
mean 'commerically-manufactured underglazes'?
(...and the pedant rears its ugly head...) ;)


>one solution I found was to test adding minute
>amounts of a clear transparent glaze that works
>on your clay body to velvet underglazes...


This is a very handy shortcut. It's nice to
develop your own, but if a commercial product
is close to what you are after, and reliance
on that source of supply isn't an issue, it's a
great convenience. I did this often (with other
products - I don't like the Velvets) when I
lived near a supplier, and specially when worked
for one. Now, it's hours of driving through Donner
Pass just to buy a jar of commercial underglaze,
so it's become easier for me to work from scratch.

It's sort of a variation on the seat-of-the-pants
'take a clay body, and add flux, calcined clay,
and colorants to suit' method.

'From scratch' is not an inherent moral virtue. ;)
It's a means to an end, and so is the use of
commercial products. Each has its advantages and
drawbacks. Everbody gets to pick their preference.


-Snail Scott
Reno, Nevada, USA, Earth

Bobbruch1@AOL.COM on thu 6 may 04


Snail Scott writes
Bob B wrote: >I haven't tried this with engobes,=20
but I have asked the same questions about underglazes ...
////////Remember, underglazes ARE engobes! Did you
mean 'commerically-manufactured underglazes'?
(...and the pedant rears its ugly head...)=A0=A0 ;)

yes


>one solution I found was to test adding minute
>amounts of a clear transparent glaze that works
>on your clay body to velvet underglazes...
////////This is a very handy shortcut. It's nice to
develop your own, but if a commercial product
is close to what you are after, and reliance
on that source of supply isn't an issue, it's a
great convenience. I did this often (with other
products - I don't like the Velvets) when I
lived near a supplier, and specially when worked
for one. Now, it's hours of driving through Donner
Pass just to buy a jar of commercial underglaze,
so it's become easier for me to work from scratch.

Snail, I thought that there were some issues with
making undergalzes from scratch that made this
process relatively complicated to do in the average
studio .... aren't there solvents that could be a problem
or I am thinking of something other than undetglazes?

Bob Bruch

Snail Scott on fri 7 may 04


At 09:07 PM 5/5/04 -0700, you wrote:
>are you sure Snail...sure .. .that you as a =sculpture
>artist cannot even recommend a basic glaze with which
>you started?


My favorite surface is to use a red/brown clay
with an oxide wash emphasize texture and give
a range of tone to a piece - sort of like a
sepia-tone photo. Reduction-fired clay has a
richness all by itself which I love, but an oxide
wash can go a long way toward giving variation
and depth to oxidation-fired work.


....I cannot imagine that someone with your
>knowledge does not know a recipe off the top of your
>head? HAHA


Truly! I don't use a lot of glaze, and when I mix
a little, it lasts me a long time, so I seldom
remember them between batches; that's why I write
them down! I just don't remember.

One recipe called 'august engobe' by Richard
Zakin has served me well, and I'm fairly sure
it's in the archives. I mixed up a big dry batch
years ago, and I'm still using it up.

I also use commercial underglazes pretty often
when I need just a bit of something. I use so
little that the cost is not a major concern, and
since I'm not in production, consistency isn't
a problem, either.

-Snail Scott
Reno, Nevada, USA, Earth

Snail Scott on fri 7 may 04


At 01:30 AM 5/6/04 EDT, you wrote:
>Snail, I thought that there were some issues with
>making undergalzes from scratch that made this
>process relatively complicated to do in the average
>studio .... aren't there solvents that could be a problem
>or I am thinking of something other than undetglazes?


Luster-type overglazes often use toxic solvents;
perhaps that's what you're thinking of?

-Snail Scott
Reno, Nevada, USA, Earth

Sumi von Dassow on tue 22 nov 11


Jeannean

Weighing is much more accurate. If your recipe is in tenths or 100ths of
a gram you'll only approximate
those amounts with dry measurements. If you use simple recipes with
rounded off percentages measuring
might be accurate enough. I've done what you suggested with some recipes
in the past, and I remember
my high school pottery teacher made glazes with a measuring cup.

By the way, as a cook I prefer to weigh out my ingredients, also. Makes
bread baking much more
consistent and reduces the number of dirty cups.

Sumi
> Is there a reason we weigh ingredients instead of measuring them? Or is
> this one of those things that we do because that's how it's always been
> done?
>
> I'm thinking of weighing then measuring ingredients of my basic recipes s=
o
> I can just measure them out in the future. Seems like it would be easier.
> But then, I'm more comfortable as a baker than as a chemist.
>
> Jeannean
> Spider Hole Pottery
> Astoria, OR
> ...where it's raining sideways as the wind howls and makes the whole hous=
e
> shudder...
>
>
>


--
Sumi von Dassow
www.herwheel.com
sumi@herwheel.com

Jeannean Hibbitts on tue 22 nov 11


Is there a reason we weigh ingredients instead of measuring them? Or is
this one of those things that we do because that's how it's always been
done?

I'm thinking of weighing then measuring ingredients of my basic recipes so
I can just measure them out in the future. Seems like it would be easier.
But then, I'm more comfortable as a baker than as a chemist.

Jeannean
Spider Hole Pottery
Astoria, OR
...where it's raining sideways as the wind howls and makes the whole house
shudder...

Bruce on wed 23 nov 11


Weighing is much more accurate - as a baker, you know that how tightly you
pack ingredients can substantially change the quantity measured, I'm sure.
Personally, I wish more cooking recipes used weight instead of volume,
myself. My ingredient packing skills are highly variable....

On Tuesday, November 22, 2011, Jeannean Hibbitts <
spiderholepottery@gmail.com> wrote:
> Is there a reason we weigh ingredients instead of measuring them? Or is
> this one of those things that we do because that's how it's always been
> done?
>
> I'm thinking of weighing then measuring ingredients of my basic recipes s=
o
> I can just measure them out in the future. Seems like it would be easier.
> But then, I'm more comfortable as a baker than as a chemist.
>
> Jeannean
> Spider Hole Pottery
> Astoria, OR
> ...where it's raining sideways as the wind howls and makes the whole hous=
e
> shudder...
>

Snail Scott on wed 23 nov 11


On Nov 22, 2011, at 6:23 PM, Jeannean Hibbitts wrote:
> Is there a reason we weigh ingredients instead of measuring them?

Many people use volumetric measurement instead
of weight for glazes. Occasionally, you will even see
recipes written in volumetric units, usually passed on
from someone's personal long-time studio practice. You
need to be accurate in your calculation when converting
recipes written by weight, but it's not tough...just basic
arithmetic. Find the density of each given material,
(either look it up or measure for yourself,) then multiply.
If you always make a standard-size batch, weight each
component, then identify the volume and write it down.
No math needed: henceforth just follow your new list of
total volumetric quantities per batch.

I use volume only to measure clay body ingredients,
since accuracy is less critical and it's easier to count
scoops than to weigh out large masses of material.

For glazes, however, I prefer weight, especially
when small additions like cobalt are called for. It
is also more convenient for testing, as it's tough to
be truly accurate measuring volume in small quantities.

Volumetric measurement is a method that works well
mainly for large batches, and recipes that aren't too
fussy about exact ratios. For recipes that you use
regularly in large amounts, though, it may be fine, but
be wary of compaction, which can radically alter the
mass of a given volume. If you prefer volume, however,
go right ahead. It's your studio; suit yourself.

-Snail

David Finkelnburg on wed 23 nov 11


Jeannean,
Have you ever read Elizabeth David's take on weighing bread flour?
You'd cause her to scream! Volume measure of glaze ingredients works if the
volume measure is close enough for all practical purposes. Weighing is done
to assure as precisely as possible the desired amount is used.
Dry, powdered material volume per unit weight changes with amount of
surface area--how fine a material is ground. Glazes are glass, melted on
the surface of a ceramic. Glasses are formulated by number of atoms, which
is by weight. Volume measures approximates weight, but do not equal weight
in all cases. If the grind changes between batches or sources this is
especially true.
Only you can decide if your volume measure is close enough for your
work. For example, if you're not trying to match a specific surface or
color or glaze expansion, precision may not be a big deal. On the other
hand, if you're the glaze maker for Heath ceramics and trying to match the
blue glaze on the top of a Heath ceramic plate that was made in 1960 and
has been in continuous production since, weighing ingredients very
precisely may be extremely important! Even Heath, btw, struggles to
reproduce that blue glaze consistently...
Happy Thanksgiving, American style!
Dave Finkelnburg
http://www.mattanddavesclays.com

-----------------------------
Date: Tue, 22 Nov 2011 16:23:09 -0800
From: Jeannean Hibbitts
Is there a reason we weigh ingredients instead of measuring them? Or is
this one of those things that we do because that's how it's always been
done?
I'm thinking of weighing then measuring ingredients of my basic recipes so
I can just measure them out in the future. Seems like it would be easier.
But then, I'm more comfortable as a baker than as a chemist.

Bonnie Staffel on wed 23 nov 11


Seems to me that you could answer your own question by looking at baking
processes. Why do you think they tell you to sift the flour before =3D
measuring
instead of dipping into the bag? There is a difference in the air =3D
floatation
ability as well as absorption of humidity of many of the ingredients =3D
which
should factor in such a practice. IMO it is better to weigh for =3D
consistency
in the case of glaze or clay materials.

Bonnie

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