Michele Hartung on thu 6 may 10
Hi Friends,
I am continually running short on EPK, since it appears in all of my
recipes. I have a large bin of OM-4 Ball Clay and was wondering if anyone
knows what adjustment to make to substitute the Ball Clay for the EPK?
Thanks so much,
Michele Hartung
Owensboro, Ky
Taylor Hendrix on thu 6 may 10
I have calculation software that would make subbing pretty accurate,
but at one time I tried a little experiment after some encouragement
by Dave F and Ron R. I made up batches of my regular glazes with both
epk and ball clay, one-to-one substitution.
I could see no difference in the physical appearance of the fired
glaze between the epk version and the ball clay version. In most cases
the slob characteristics of the glaze was improved. My glazes are cone
5 and 6 ox glazes.
I offer this information for whatever it is worth.
Taylor, in Rockport TX
wirerabbit1 on Skype (-0600 UTC)
http://wirerabbit.blogspot.com
http://wirerabbitpots.blogspot.com
http://www.flickr.com/photos/wirerabbit/
On Thu, May 6, 2010 at 2:05 PM, Michele Hartung
wrote:
> Hi Friends,
>
> I am continually running short on EPK, since it appears in all of my
> recipes. =3DC2=3DA0I have a large bin of OM-4 Ball Clay and was wondering=
if =3D
anyone
> knows what adjustment to make to substitute the Ball Clay for the EPK?
...
Ron Roy on thu 6 may 10
Hi Michele,
This kind of thing is easy to do using calculation software - I've
done two conversions for you based on some sample recipes I just made
up.
The First one has 10% EPK - the second one has the 10% EPK replaced
with OM-4 ball.
Number three has 20% EPK - the 4th is with the 20% EPK replaced with
OM-4 ball.
I did not re-total either conversion.
You can figure out how to replace any amount of EPK with OM-4 using
the examples - or send me the recipes you want converted and I'll do
them for you.
#1
25.00 F3134
25.00 CUSTER SPAR
15.00 WHITING
10.00 EPK
25.00 SILICA
Total - 100
0.74* CaO
0.00* MgO
0.08* K2O
0.17* Na2O
0.00 Fe2O3
0.00 TiO2
0.26 B2O3
0.25 Al2O3
3.04 SiO2
0.00 P2O5
Si:Al: 12.33
SiB:Al: 13.38
Thermal Expansion: 502.78
Formula Weight: 286.33
#1 with OM-4 and no EPK
25.00 F3134
25.00 CUSTER SPAR
15.00 WHITING
14.00 OM-4
23.00 SILICA
Total - 102.0
0.74* CaO
0.01* MgO
0.09* K2O
0.17* Na2O
0.00 Fe2O3
0.01 TiO2
0.26 B2O3
0.25 Al2O3
3.07 SiO2
Si:Al: 12.33
SiB:Al: 13.36
Thermal Expansion: 503.43
Formula Weight: 288.67
#2 with 20% EPK
25.00 F3134
20.00 CUSTER SPAR
15.00 WHITING
20.00 EPK
20.00 SILICA
Total - 100.0
0.76* CaO
0.00* MgO
0.07* K2O
0.16* Na2O
0.00 Fe2O3
0.00 TiO2
0.26 B2O3
0.34 Al2O3
2.90 SiO2
0.00 P2O5
Si:Al: 8.49
SiB:Al: 9.26
Thermal Expansion: 487.62
Formula Weight: 288.11
#2 with OM-4 replacing EPK
25.00 F3134
20.00 CUSTER SPAR
15.00 WHITING
28.00 OM-4
16.00 SILICA
Total - 104.0
0.75* CaO
0.01* MgO
0.08* K2O
0.16* Na2O
0.01 Fe2O3
0.01 TiO2
0.26 B2O3
0.34 Al2O3
2.96 SiO2
Si:Al: 8.59
SiB:Al: 9.34
Thermal Expansion: 489.47
Formula Weight: 292.81
You can see how close these revisions are by looking at the amounts of
the oxides, the ratio, the expansion and the molecular formulas.
RR
Quoting Michele Hartung :
> Hi Friends,
>
> I am continually running short on EPK, since it appears in all of my
> recipes. I have a large bin of OM-4 Ball Clay and was wondering if anyon=
e
> knows what adjustment to make to substitute the Ball Clay for the EPK?
>
> Thanks so much,
>
> Michele Hartung
> Owensboro, Ky
>
Steve Slatin on thu 6 may 10
Michele --
For the most part I would not recommend this
substitution. The reason is that while you
can fairly readily sub for the chemical content
of the two materials, there are non-chemical
issues in the difference between them.
Most glaze recipes rely on particle size and=3D20
expansion characteristics of the clay components
to work properly. In these respects, the two
materials are quite different.
Steve Slatin --=3D20
--- On Thu, 5/6/10, Michele Hartung wrote:
> From: Michele Hartung
> Subject: EPK vs Ball Clay
> To: Clayart@LSV.CERAMICS.ORG
> Date: Thursday, May 6, 2010, 12:05 PM
> Hi Friends,
>=3D20
> I am continually running short on EPK, since it appears in
> all of my
> recipes.=3DA0 I have a large bin of OM-4 Ball Clay and was
> wondering if anyone
> knows what adjustment to make to substitute the Ball Clay
> for the EPK?
>=3D20
> Thanks so much,
>=3D20
> Michele Hartung
> Owensboro, Ky
> =3D0A=3D0A=3D0A
John Post on thu 6 may 10
Taylor wrote:
> In most cases
> the slob characteristics of the glaze was improved.
Taylor,
I'm sure you mistyped and meant to write "slop characteristics"
instead of "slob characteristics", but if by some miracle you have
managed to find a way to reduce the slob characteristics of glazing I
would love to hear about it.
Today I glazed clay mummy time capsules with 100 twelve 12-year-old
kids. When you're working with a classroom full of kids, you don't
have to look very hard to determine which kids excel at slobbiness and
which kids have a good grasp of working with their hands.
Some kids fail to realize that if you are glazing a hollow sculpture,
the glaze that flows inside, at some point is going to come pouring
out. Every year at least one kid has to find out the hard way by
glazing his shoes or pants. Today it was Mark.
If you are wondering what a clay mummy time capsule looks like, I have
two videos of how we make them on my youtube page.
John Post
Sterling Heights, Michigan
:: cone 6 glaze website :: http://www.johnpost.us
:: elementary art website :: http://www.wemakeart.org
:: youtube channel :: http://www.youtube.com/user/MrPostArtTeacher
ivor & olive lewis on fri 7 may 10
Dear Michele Hartung,
<< I am continually running short on EPK, since it appears in all of my
recipes. I have a large bin of OM-4 Ball Clay and was wondering if anyone
knows what adjustment to make to substitute the Ball Clay for the EPK?>>
I suggest you have a look at the oxide analyses of these two clays.
In particular compare the SiO2 and Al2O3 values. As a rough guide, Kaolin
will have a lower silica to alumina ratio than ball clay while ball clay
will have will have a higher silica to alumina ratio than kaolin. Any
adjustment would require an addition of Alumina. According to Carty and
Senapati, domestic (USA) ball clays may have as much as 35 percent quarts
(SiO2) as an impurity. Getting the right silica to alumina balance might be
difficult to achieve without elevating the maturity temperature of your
glazes.
Best regards,
Ivor Lewis,
Redhill,
South Australia
Eric Hansen on fri 7 may 10
Michele: EPK simply means "Edgar Plastic Kaolin" it comes from Florida. Any
plastic kaolin will be an acceptable substitution. EPK just happens to be
the cheapest. So cheap you ought to just buy it by the 50 lb. or 100 lb. ba=
g
if you keep running out. the only cheaper kaolin is if you dig it yourself.
OM4 is a whole different can of worms. Good luck on that one : ) h a n
s e n
On Thu, May 6, 2010 at 3:05 PM, Michele Hartung
wrote:
> Hi Friends,
>
> I am continually running short on EPK, since it appears in all of my
> recipes. I have a large bin of OM-4 Ball Clay and was wondering if anyon=
e
> knows what adjustment to make to substitute the Ball Clay for the EPK?
>
> Thanks so much,
>
> Michele Hartung
> Owensboro, Ky
>
Edouard Bastarache on fri 7 may 10
" OM4 is a whole different can of worms. Good luck on that one : ) h a
n"
Eric,
OM-4 is the one I use to try to make surface flaws in shinos.
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://blogsalbertbastarache.blogspot.com/
http://cerampeintures.blogspot.com/
http://perso.wanadoo.fr/smart2000/index.htm
Rimas VisGirda on fri 7 may 10
In the 60's and 70's we uses Lincoln 60 (fireclay) for our clay body and EP=
=3D
K for glazes. Once, we ran out of EPK and subbed the Lincoln 60=3DA0one to =
on=3D
e. I found no appreciable difference in the fired glaze. Currently I sub OM=
=3D
-4 for EPK in all my glazes that I will decorate by wax inlay, the OM-4 "ha=
=3D
rdens" the raw glaze and allows the wax to "stick" better. With EPK I had t=
=3D
rouble with the wax peeling from the fluffy glaze surface as I dragged my t=
=3D
ool accross it. -Rimas
Michele Hartung on fri 7 may 10
Ron,
Thank you for your answer. However, I think I've created a monster. My
husband is a materials science engineer, and I asked him to look at your
answer with me to see the relationship between EPK and OM-4. He had me rea=
d
the section of your book about the unity formula, and declared that he
needed to read the whole book, and devise a glaze calculation formula in an
excel format. It was just the spark of interest I have been looking for in
a long time, as I cannot see him throwing clay, but making glazes together
could be a new source of fun!
Michele
On Thu, May 6, 2010 at 5:23 PM, wrote:
> Hi Michele,
>
> This kind of thing is easy to do using calculation software - I've done t=
wo
> conversions for you based on some sample recipes I just made up.
>
> The First one has 10% EPK - the second one has the 10% EPK replaced with
> OM-4 ball.
>
> Number three has 20% EPK - the 4th is with the 20% EPK replaced with OM-4
> ball.
>
> I did not re-total either conversion.
>
> You can figure out how to replace any amount of EPK with OM-4 using the
> examples - or send me the recipes you want converted and I'll do them fo=
r
> you.
>
> #1
> 25.00 F3134
> 25.00 CUSTER SPAR
> 15.00 WHITING
> 10.00 EPK
> 25.00 SILICA
> Total - 100
>
> 0.74* CaO
> 0.00* MgO
> 0.08* K2O
> 0.17* Na2O
> 0.00 Fe2O3
> 0.00 TiO2
> 0.26 B2O3
> 0.25 Al2O3
> 3.04 SiO2
> 0.00 P2O5
>
> Si:Al: 12.33
> SiB:Al: 13.38
> Thermal Expansion: 502.78
> Formula Weight: 286.33
>
> #1 with OM-4 and no EPK
>
> 25.00 F3134
> 25.00 CUSTER SPAR
> 15.00 WHITING
> 14.00 OM-4
> 23.00 SILICA
> Total - 102.0
>
> 0.74* CaO
> 0.01* MgO
> 0.09* K2O
> 0.17* Na2O
> 0.00 Fe2O3
> 0.01 TiO2
> 0.26 B2O3
> 0.25 Al2O3
> 3.07 SiO2
>
> Si:Al: 12.33
> SiB:Al: 13.36
> Thermal Expansion: 503.43
> Formula Weight: 288.67
>
> #2 with 20% EPK
>
> 25.00 F3134
> 20.00 CUSTER SPAR
> 15.00 WHITING
> 20.00 EPK
> 20.00 SILICA
> Total - 100.0
>
> 0.76* CaO
> 0.00* MgO
> 0.07* K2O
> 0.16* Na2O
> 0.00 Fe2O3
> 0.00 TiO2
> 0.26 B2O3
> 0.34 Al2O3
> 2.90 SiO2
> 0.00 P2O5
>
> Si:Al: 8.49
> SiB:Al: 9.26
> Thermal Expansion: 487.62
> Formula Weight: 288.11
>
> #2 with OM-4 replacing EPK
>
> 25.00 F3134
> 20.00 CUSTER SPAR
> 15.00 WHITING
> 28.00 OM-4
> 16.00 SILICA
> Total - 104.0
>
> 0.75* CaO
> 0.01* MgO
> 0.08* K2O
> 0.16* Na2O
> 0.01 Fe2O3
> 0.01 TiO2
> 0.26 B2O3
> 0.34 Al2O3
> 2.96 SiO2
>
> Si:Al: 8.59
> SiB:Al: 9.34
> Thermal Expansion: 489.47
> Formula Weight: 292.81
>
> You can see how close these revisions are by looking at the amounts of th=
e
> oxides, the ratio, the expansion and the molecular formulas.
>
> RR
>
>
> Quoting Michele Hartung :
>
> Hi Friends,
>>
>> I am continually running short on EPK, since it appears in all of my
>> recipes. I have a large bin of OM-4 Ball Clay and was wondering if anyo=
ne
>> knows what adjustment to make to substitute the Ball Clay for the EPK?
>>
>> Thanks so much,
>>
>> Michele Hartung
>> Owensboro, Ky
>>
>>
>
>
>
Carl Cravens on fri 7 may 10
On 05/06/2010 08:15 PM, John Post wrote:
> If you are wondering what a clay mummy time capsule looks like, I have
> two videos of how we make them on my youtube page.
John, that's very cool... I like your clear presentation, both verbal and v=
isual.
My nine-year-old son loves to hand-build, but has trouble finding "inspirat=
ion". And if Dad makes a suggestion, you can bet that is the *last* thing =
he's going to build. :) I bet if I put these videos on his desktop, he'll =
be begging me to get out the clay. (And buy an extruder!)
Is there a part-three coming, or do I just fill in the blanks? You call it=
a "time capsule"... what kind of stuff are the kids putting in it, and how=
are you sealing it?
I remember pottery in school. Made my first art sale in the seventh grade.=
.. to a para who eventually became my step-grandmother, before my mom had =
met my step-dad. The piece was given back to me as a gift nearly twenty ye=
ars later. I still use a slab-built lidded jar I made the same year. My c=
oil-built "Ugly Pot" (it's artistic sculpture!, and the only piece I've giv=
en a name :) from my freshman year still sits in my mom's living room.
Of all the stuff I did in school, the pottery is about all I have left. (I=
have a silver ring from silver-smithing class somewhere, and a bookshelf f=
rom wood shop.) And those school experiences are ones that stand out in my=
memory. I hated school (bullies, mean teachers, not fitting in, "stupid" =
classes), and art classes are the bright spots amid dreary and fearful days=
, because I had good art teachers. You are doing a good thing, Mr Post, Ar=
t Teacher. Thanks for sharing with the rest of us.
(800 students!? My gosh, how do you manage report card season?)
--
Carl D Cravens (raven@phoenyx.net)
...and BTW, OTOH (FWIW), IMHO it's OK.
douglas fur on sat 8 may 10
Dear Michele Hartung,
I've used OM4 in glazes for years. Long enough that I've forgotten what
little difference it made. My origonal intent was to have more plasticity
for raw glazing and to simplify my materials stock.
I'd say try it and see how the glazes come out.
DRB
Burien
| |
|
