jonathan byler on thu 26 apr 12
I talked to him for a few minutes in seattle, and he was saying all
his stuff goes in the electric kiln now. he fires electric for oil
spotting, IIRC, and does the SiC copper reds so he doesn't have to run
two different kilns. smart man., and he gets what he wants - results.
On Apr 26, 2012, at 9:43 PM, William & Susan Schran User wrote:
> On 4/26/12 6:12 PM, "Robert Harris" wrote:
>
>> After seeing the Skutt advert on the back of Clay Times, with Tom
>> Turner looking very reflective (and pleased!), I saw that he had some
>> spectacular copper reds. Well, I went to his website, and he claims
>> that these are done with chemical reduction. I'd assume this is SiC,
>> but frankly I wouldn't want to assume anything right now.
>> http://tomturnerporcelain.com/page084.htm
>> Having messed around with SiC a few years ago, I'm inspired by these
>> photos to try again. It looks to me like a couple of the glazes might
>> have a boron blue haze (but of course photos are a bit tricky to
>> interpret).
>> So how is he doing it?
>
> Tom uses a porcelain body he originally formulated that has top
> temperature of about cone 9. I'm sure he's using SiC to get the
> copper red
> glaze.
>
> In his book "Glazes for Special Effects", Herbert Sanders has a
> section on
> localized reduction copper reds. Apparently very little copper and
> silicon
> carbide are used. In most recipes only call for .3% copper carb and
> between .2% - 1% FFF grain silicon carbide. He also uses .5% - 1% tin
> oxide and calcined borax at 2% - 6%. He also states a longer firing is
> preferred.
>
> Bill
> --
> William "Bill" Schran
> wschran@cox.net
> wschran@nvcc.edu
> http://www.creativecreekartisans.com
>
>
>>
Robert Harris on thu 26 apr 12
After seeing the Skutt advert on the back of Clay Times, with Tom
Turner looking very reflective (and pleased!), I saw that he had some
spectacular copper reds. Well, I went to his website, and he claims
that these are done with chemical reduction. I'd assume this is SiC,
but frankly I wouldn't want to assume anything right now.
http://tomturnerporcelain.com/page084.htm
Having messed around with SiC a few years ago, I'm inspired by these
photos to try again. It looks to me like a couple of the glazes might
have a boron blue haze (but of course photos are a bit tricky to
interpret).
So how is he doing it?
I've ordered myself some 800 grit SiC off Amazon, and I'm hoping that
will be fine enough. I've also trawled through the archives, and while
this seemed to be a hot topic in the 90's nobody has really had much
to say on electric reds recently.
I do fire to Cone 9 1/2 (Cone 10 at 2pm or so), so my current plan is
to just chuck some SiC into some of the reds in John Britt's book. Any
other ideas?
I usually fire with a vent, but I'm guessing I should skip this
(kiln's in a separate garage so that's not too much of an issue as
long as I don't hang around.) It's a round Cone Art Kiln, but the lid
doesn't exactly seat firmly on top, there is always a 1/8-1/4" gap. Is
this going to nix the idea?
Any thoughts would be useful.
Robert
--
----------------------------------------------------------
William & Susan Schran User on thu 26 apr 12
On 4/26/12 6:12 PM, "Robert Harris" wrote:
>After seeing the Skutt advert on the back of Clay Times, with Tom
>Turner looking very reflective (and pleased!), I saw that he had some
>spectacular copper reds. Well, I went to his website, and he claims
>that these are done with chemical reduction. I'd assume this is SiC,
>but frankly I wouldn't want to assume anything right now.
>http://tomturnerporcelain.com/page084.htm
>Having messed around with SiC a few years ago, I'm inspired by these
>photos to try again. It looks to me like a couple of the glazes might
>have a boron blue haze (but of course photos are a bit tricky to
>interpret).
>So how is he doing it?
Tom uses a porcelain body he originally formulated that has top
temperature of about cone 9. I'm sure he's using SiC to get the copper red
glaze.
In his book "Glazes for Special Effects", Herbert Sanders has a section on
localized reduction copper reds. Apparently very little copper and silicon
carbide are used. In most recipes only call for .3% copper carb and
between .2% - 1% FFF grain silicon carbide. He also uses .5% - 1% tin
oxide and calcined borax at 2% - 6%. He also states a longer firing is
preferred.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
>
Steve Mills on fri 27 apr 12
Hi Robert
We used to sell 1200 grade SiC for localised reduction effect. Mike Bailey =
(=3D
our partner) always recommended the finest grade you could get, anything co=
a=3D
rser than that can produce a sort of "volcanic" effect.=3D20
On another subject; you mention your kiln lid "gaps" a bit. If that's at th=
e=3D
front, a bit of adjustment of the hinge should cure that. Kiln lid hinges =
a=3D
re usually very simple beasts and easy to modify/loosen up!
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 26 Apr 2012, at 23:12, Robert Harris wrote:
> After seeing the Skutt advert on the back of Clay Times, with Tom
> Turner looking very reflective (and pleased!), I saw that he had some
> spectacular copper reds. Well, I went to his website, and he claims
> that these are done with chemical reduction. I'd assume this is SiC,
> but frankly I wouldn't want to assume anything right now.
>=3D20
> http://tomturnerporcelain.com/page084.htm
>=3D20
> Having messed around with SiC a few years ago, I'm inspired by these
> photos to try again. It looks to me like a couple of the glazes might
> have a boron blue haze (but of course photos are a bit tricky to
> interpret).
>=3D20
> So how is he doing it?
>=3D20
> I've ordered myself some 800 grit SiC off Amazon, and I'm hoping that
> will be fine enough. I've also trawled through the archives, and while
> this seemed to be a hot topic in the 90's nobody has really had much
> to say on electric reds recently.
>=3D20
> I do fire to Cone 9 1/2 (Cone 10 at 2pm or so), so my current plan is
> to just chuck some SiC into some of the reds in John Britt's book. Any
> other ideas?
>=3D20
> I usually fire with a vent, but I'm guessing I should skip this
> (kiln's in a separate garage so that's not too much of an issue as
> long as I don't hang around.) It's a round Cone Art Kiln, but the lid
> doesn't exactly seat firmly on top, there is always a 1/8-1/4" gap. Is
> this going to nix the idea?
>=3D20
> Any thoughts would be useful.
>=3D20
>=3D20
> Robert
> --
> ----------------------------------------------------------
Steve Slatin on fri 27 apr 12
I had some giving good reds a few years back -- what I=3D0Afound the SiC ne=
ed=3D
ed was to be deep -- you can get the=3D0Aresult by 'painting' SiC (very, ve=
ry=3D
thin) onto the surface of=3D0Aa pot and putting a glaze that should be red=
i=3D
n reduction=3D0Aon top.=3DA0 I was never able to find a way to paint a cons=
iste=3D
nt=3D0Aand yet thin surface onto the pot, so that didn't work --=3D0A=3DA0=
=3D0AThen=3D
I painted onto the exterior of the glaze layer.=3DA0 I=3D0Agot virtually n=
o re=3D
d.=3D0A=3DA0=3D0AMixed into the glaze, if the glaze was thin I didn't have=
=3D0Aany =3D
red.=3DA0=3DA0 If the glaze was thick, I had red and pinholing.=3D0AHolding=
the k=3D
iln at about 90 degrees off top temp for=3D0A30 minutes healed most of the =
pi=3D
nholes, but the red =3D0Aonly developed where the glaze was thick.=3DA0 Els=
ewhe=3D
re,=3D0Ait was that off-white or pale gray or whatever.=3DA0 Also, if=3D0AI=
held =3D
the kiln for either substantially less OR substantially=3D0Amore time than =
th=3D
e 30 minutes, I got more pinholing=3D0Aagain.=3D0A=3DA0=3D0AThe glaze was r=
unny, an=3D
d I broke open some thick=3D0Aparts for visual inspection -- the glaze was =
pe=3D
rmeated=3D0Awith bubbles, mostly fairly large.=3D0A=3D0ASteve Slatin -- =3D=
0A=3D0A=3D0A=3D
N48.0886450=3D0AW123.1420482 =3D0A=3D0A=3D0A----- Original Message -----=3D=
0AFrom: Ro=3D
bert Harris =3D0ATo: Clayart@LSV.CERAMICS.ORG=3D0A=
Cc: =3D
=3D0ASent: Thursday, April 26, 2012 5:12 PM=3D0ASubject: Tom Turner's elect=
ric =3D
red.=3D0A=3D0AAfter seeing the Skutt advert on the back of Clay Times, with=
Tom=3D
=3D0ATurner looking very reflective (and pleased!), I saw that he had some=
=3D0A=3D
spectacular copper reds. Well, I went to his website, and he claims=3D0Atha=
t =3D
these are done with chemical reduction. I'd assume this is SiC,=3D0Abut fra=
nk=3D
ly I wouldn't want to assume anything right now.=3D0A=3D0Ahttp://tomturnerp=
orce=3D
lain.com/page084.htm=3D0A=3D0AHaving messed around with SiC a few years ago=
, I'=3D
m inspired by these=3D0Aphotos to try again. It looks to me like a couple o=
f =3D
the glazes might=3D0Ahave a boron blue haze (but of course photos are a bit=
t=3D
ricky to=3D0Ainterpret).=3D0A=3D0ASo how is he doing it?=3D0A=3D0AI've orde=
red myself=3D
some 800 grit SiC off Amazon, and I'm hoping that=3D0Awill be fine enough.=
I=3D
've also trawled through the archives, and while=3D0Athis seemed to be a ho=
t =3D
topic in the 90's nobody has really had much=3D0Ato say on electric reds re=
ce=3D
ntly.=3D0A=3D0AI do fire to Cone 9 1/2 (Cone 10 at 2pm or so), so my curren=
t pl=3D
an is=3D0Ato just chuck some SiC into some of the reds in John Britt's book=
. =3D
Any=3D0Aother ideas?=3D0A=3D0AI usually fire with a vent, but I'm guessing =
I shou=3D
ld skip this=3D0A(kiln's in a separate garage so that's not too much of an =
is=3D
sue as=3D0Along as I don't hang around.) It's a round Cone Art Kiln, but th=
e =3D
lid=3D0Adoesn't exactly seat firmly on top, there is always a 1/8-1/4" gap.=
I=3D
s=3D0Athis going to nix the idea?=3D0A=3D0AAny thoughts would be useful.=3D=
0A=3D0A=3D0A=3D
Robert=3D0A--=3D0A---------------------------------------------------------=
-=3D0A
Ben Morrison on fri 27 apr 12
So would that technique work with the SiC mixed into a refractory slip and =
=3D
painted on under a glaze? =3D0A=3D0A=3D0A-Ben=3D0A=3D0A=3D0A=3D0A__________=
______________=3D
________=3D0A From: Steve Slatin =3D0ATo: Clayart@L=
SV.C=3D
ERAMICS.ORG =3D0ASent: Friday, April 27, 2012 9:01 AM=3D0ASubject: Re: Tom =
Turn=3D
er's electric red.=3D0A =3D0AI had some giving good reds a few years back -=
- wh=3D
at I=3D0Afound the SiC needed was to be deep -- you can get the=3D0Aresult =
by '=3D
painting' SiC (very, very thin) onto the surface of=3D0Aa pot and putting a=
g=3D
laze that should be red in reduction=3D0Aon top.=3DA0 I was never able to f=
ind =3D
a way to paint a consistent=3D0Aand yet thin surface onto the pot, so that =
di=3D
dn't work --=3D0A=3DA0=3D0AThen I painted onto the exterior of the glaze la=
yer.=3D
=3DA0 I=3D0Agot virtually no red.=3D0A=3DA0=3D0AMixed into the glaze, if th=
e glaze wa=3D
s thin I didn't have=3D0Aany red.=3DA0=3DA0 If the glaze was thick, I had r=
ed and=3D
pinholing.=3D0AHolding the kiln at about 90 degrees off top temp for=3D0A3=
0 mi=3D
nutes healed most of the pinholes, but the red =3D0Aonly developed where th=
e =3D
glaze was thick.=3DA0 Elsewhere,=3D0Ait was that off-white or pale gray or =
what=3D
ever.=3DA0 Also, if=3D0AI held the kiln for either substantially less OR su=
bsta=3D
ntially=3D0Amore time than the 30 minutes, I got more pinholing=3D0Aagain.=
=3D0A=3D
=3DA0=3D0AThe glaze was runny, and I broke open some thick=3D0Aparts for vi=
sual i=3D
nspection -- the glaze was permeated=3D0Awith bubbles, mostly fairly large.=
=3D
=3D0A=3D0ASteve Slatin -- =3D0A=3D0A=3D0AN48.0886450=3D0AW123.1420482 =3D0A=
=3D0A=3D0A----- Or=3D
iginal Message -----=3D0AFrom: Robert Harris =3D0A=
To: =3D
Clayart@LSV.CERAMICS.ORG=3D0ACc: =3D0ASent: Thursday, April 26, 2012 5:12 P=
M=3D0A=3D
Subject: Tom Turner's electric red.=3D0A=3D0AAfter seeing the Skutt advert =
on t=3D
he back of Clay Times, with Tom=3D0ATurner looking very reflective (and ple=
as=3D
ed!), I saw that he had some=3D0Aspectacular copper reds. Well, I went to h=
is=3D
website, and he claims=3D0Athat these are done with chemical reduction. I'=
d =3D
assume this is SiC,=3D0Abut frankly I wouldn't want to assume anything righ=
t =3D
now.=3D0A=3D0Ahttp://tomturnerporcelain.com/page084.htm=3D0A=3D0AHaving mes=
sed arou=3D
nd with SiC a few years ago, I'm inspired by these=3D0Aphotos to try again.=
I=3D
t looks to me like a couple of the glazes might=3D0Ahave a boron blue haze =
(b=3D
ut of course photos are a bit tricky to=3D0Ainterpret).=3D0A=3D0ASo how is =
he doi=3D
ng it?=3D0A=3D0AI've ordered myself some 800 grit SiC off Amazon, and I'm h=
opin=3D
g that=3D0Awill be fine enough. I've also trawled through the archives, and=
w=3D
hile=3D0Athis seemed to be a hot topic in the 90's nobody has really had mu=
ch=3D
=3D0Ato say on electric reds recently.=3D0A=3D0AI do fire to Cone 9 1/2 (Co=
ne 10 =3D
at 2pm or so), so my current plan is=3D0Ato just chuck some SiC into some o=
f =3D
the reds in John Britt's book. Any=3D0Aother ideas?=3D0A=3D0AI usually fire=
with =3D
a vent, but I'm guessing I should skip this=3D0A(kiln's in a separate garag=
e =3D
so that's not too much of an issue as=3D0Along as I don't hang around.) It'=
s =3D
a round Cone Art Kiln, but the lid=3D0Adoesn't exactly seat firmly on top, =
th=3D
ere is always a 1/8-1/4" gap. Is=3D0Athis going to nix the idea?=3D0A=3D0AA=
ny tho=3D
ughts would be useful.=3D0A=3D0A=3D0ARobert=3D0A--=3D0A--------------------=
----------=3D
----------------------------
William & Susan Schran User on fri 27 apr 12
On 4/27/12 2:14 PM, "Ben Morrison" wrote:
>So would that technique work with the SiC mixed into a refractory slip
>and painted on under a glaze?
>
>Sanders does mention adding the Sic into a slip then applying glaze over
>that. The one thing that he writes is that the glaze needs to be applied
>on the thick side, so protect your shelves!
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Steve Slatin on sat 28 apr 12
Ben --=3D0ASiC doesn't suspend well, and keeping it in a slurry requires re=
gu=3D
lar and=3D0Avigorous mixing.=3DA0 Whether it'd work mixed into a slip which=
is =3D
then painted=3D0Aonto work I can't say -- I got red freckles mixing it with=
a=3D
cornstarch-based=3D0Aslurry that I painted on, but perhaps it wasn't prope=
rl=3D
y distributed.=3DA0 I didn't=3D0Atry everything, so there's lots of possibi=
liti=3D
es, but I did find that the approach=3D0Aof mixing it into the glaze and st=
ir=3D
ring like crazy worked best for me.=3DA0 And=3D0Apainting it with nothing t=
o su=3D
spend it in but water on top of the glaze did=3D0Aworst.=3D0A=3DA0=3D0AThat=
, of cou=3D
rse, is no proof of anything for anyone else.=3D0A=3D0ASteve Slatin -- =3D0=
A=3D0A=3D
=3D0AN48.0886450=3D0AW123.1420482=3D0A=3D0A=3D0A___________________________=
_____=3D0AFr=3D
om: Ben Morrison =3D0ATo: Steve Slatin ah=3D
oo.com>; "Clayart@LSV.CERAMICS.ORG" =3D0ASent: F=
ri=3D
day, April 27, 2012 1:14 PM=3D0ASubject: Re: Tom Turner's electric red.=3D0=
A=3D0A=3D
=3D0ASo would that technique work with the SiC mixed into a refractory slip=
a=3D
nd painted on under a glaze? =3D0A=3D0A=3D0A-Ben=3D0A=3D0A=3D0A=3D0A_______=
______________=3D
___________=3D0A
Robert Harris on sat 28 apr 12
Thank you, everybody, for your replies.
Having done a bit of searching on the web, I can say that 800 grit SiC
(the finest I could find easily for retail) is marginally finer than
FFF grade (F to FFFF having a broader range of particle sizes
compared to numbered 'grits'.). 1500 grit is also available (although
I my have to buy 10 pounds), which may be something to look into if I
still have problems with suspending the SiC and/or getting speckles.
Almost everyone agrees that Copper Reds need to flow and be low in
Alumina. This obviously means that the glaze is low in clay, and
therefore is likely to have suspension problems anyway. I note that
most Copper Red recipes (even without SiC) have large amounts of
bentonite (3-6%) in them - presumably to remedy this problem. I wonder
if the addition of something like Veegum T to the glaze would help
suspend the SiC.
Most people also seem to mention that the glaze needs to be applied
relatively thickly, and that the addition of Tin Oxide (in an
approximately 3:1 ratio with CuCo3) is necessary for copper reds. Also
most of the glazes seem to be high in K and Na, rather than Ca.
Obviously copper reds craze like anything.
I will let you know how my experiments go.
I did briefly think of ball milling the SiC and CuCo3 with a bit of
glaze, but since SiC is harder than fired porcelain, I'm not sure how
well this would actually work. Anybody have any thoughts about this?
Thanks again to everyone.
Robert
Url Krueger on sat 28 apr 12
Robert,
How about using CMC as a suspending agent?
earl in Oregon
Impatiently waiting to see what's in
Oregon Potters Association Showcase
next week. Y'all come.
Robert Harris on sat 28 apr 12
Hmmm possibly. I know I have Veegum T, not sure if I've got any CMC at
the moment. Perhaps lurking somewhere.
I do know that I would want a suspending agent that will work with
high density grains, and (I'm assuming) is not dependent on clays
(electrostatic charge?). I'm not sure if SiC would carry any sort of a
charge that would help. I doubt it.
I forget the mechanism of action of Veegum T and CMC. One, no doubt,
is more suitable.
I think that is a Ron Roy question - Ron, any thoughts?
Robert
On Sat, Apr 28, 2012 at 3:53 PM, Url Krueger wrote:
> Robert,
>
> How about using CMC as a suspending agent?
>
> earl in Oregon
> Impatiently waiting to see what's in
> Oregon Potters Association Showcase
> next week. =3DA0Y'all come.
--=3D20
----------------------------------------------------------
Robert Harris on sat 28 apr 12
To address your last point first, unfortunately, since I fire to Cone
9, chrome pretty much disappears in the firing. I've made a few
Chrome-tin pinks that can be quite pretty, but even those have large
areas that are totally white.
Yes, alumina does destroy copper red, however Pete's Red for example
has alumina at 0.4, due to the large amount of Custer used (73%), so I
hardly think that a few percent of Veegum T is going to disrupt the
Oxblood when added to a glaze that (for example) has alumina at 0.23
as some of the others do. Certainly there may be something of a colour
change, but I am not sure the amount of Veegum T I would add (even
less than bentonite - which 90% of the Copper red recipes in John
Britt's book call for) would have that much of an effect. Indeed there
is one post in the ClayArt archives (by David Hendley I think) that
implies that the K+/Na+ ratio that is more important in determining
the colour and shade of red.
Anyway, maybe some of the chemistry Gurus will weigh in on this one.
Thanks again for being interested.
Robert
On Sat, Apr 28, 2012 at 9:16 PM, Ben Morrison wrote:
> Because copper only turns red in the absence of alumina. Veegum T is a
> magnesia alumina silicate. Even fairly small amounts of alumina will turn=
=3D
an
> oxblood red pink. The pdf below has information on Veegum T. Cee Gum is t=
=3D
he
> one you'd want to use as the previous gentleman wrote. It's an organic
> compound that will not discolor your glaze. However I personally enjoy th=
=3D
e
> rich red color I'm getting from the Chrome/Tin Red Glaze in the Ron Roy
> book, Mastering Cone 6 glazes. I never thought I'd like a chrome/tin glaz=
=3D
e,
> but he proved me wrong. I had no idea the ration of tin to chrome needed =
=3D
to
> be so high. Since I discovered just how nice this glaze is I don't miss
> reduction nearly as much as I used to. Now if he can make me a Malcolm Da=
=3D
vis
> style Shino for oxidation I'll be set.
>
> http://www.rtvanderbilt.com/documents/psdocs/72405.pdf
>
>
>
> ________________________________
> From: Robert Harris
> To: Ben Morrison
> Cc: "Clayart@LSV.CERAMICS.ORG"
> Sent: Saturday, April 28, 2012 5:56 PM
>
> Subject: Re: Tom Turner's electric red.
>
> OK, Why?
>
> Although I have to admit I am now leaning towards floculating the
> Gerstley with muriatic acid.
>
> Robert
>
> On Sat, Apr 28, 2012 at 8:30 PM, Ben Morrison wrote=
=3D
:
>> I'm pretty sure that the Veegum T would disrupt the copper red glaze
>> entirely.
>>
>>
>> -Ben
>>
>> ________________________________
>> From: Robert Harris
>> To: Clayart@LSV.CERAMICS.ORG
>> Sent: Saturday, April 28, 2012 3:34 PM
>>
>> Subject: Re: Tom Turner's electric red.
>>
>> Hmmm possibly. I know I have Veegum T, not sure if I've got any CMC at
>> the moment. Perhaps lurking somewhere.
>>
>> I do know that I would want a suspending agent that will work with
>> high density grains, and (I'm assuming) is not dependent on clays
>> (electrostatic charge?). I'm not sure if SiC would carry any sort of a
>> charge that would help. I doubt it.
>>
>> I forget the mechanism of action of Veegum T and CMC. One, no doubt,
>> is more suitable.
>>
>> I think that is a Ron Roy question - Ron, any thoughts?
>>
>> Robert
>>
>>
>>
>> On Sat, Apr 28, 2012 at 3:53 PM, Url Krueger wrot=
=3D
e:
>>> Robert,
>>>
>>> How about using CMC as a suspending agent?
>>>
>>> earl in Oregon
>>> Impatiently waiting to see what's in
>>> Oregon Potters Association Showcase
>>> next week. =3DA0Y'all come.
>>
>>
>>
>> --
>> ----------------------------------------------------------
>>
>>
>
>
>
> --
> ----------------------------------------------------------
>
>
--=3D20
----------------------------------------------------------
pdp1@EARTHLINK.NET on sat 28 apr 12
----- Original Message -----
From: "Robert Harris"
<<<<< snip >>>>>
> I did briefly think of ball milling the SiC and CuCo3 with a bit of
> glaze, but since SiC is harder than fired porcelain, I'm not sure how
> well this would actually work. Anybody have any thoughts about this?
>
> Thanks again to everyone.
>
> Robert
Yes...I would think...get the 1500 grit.,,or even finer if possible.
Or, get solid Tungsten Carbide 'Balls' for the solid Tungsten Carbide
Cannister Ball Mill...and Mill it down fine as Cigarette Ash.
Does anyone Calcine these ingredients first?
Or would it matter if one did?
Url Krueger on sat 28 apr 12
On 04/28/2012 03:34 PM, Robert Harris wrote:
> I do know that I would want a suspending agent that will work with
> high density grains, and (I'm assuming) is not dependent on clays
> (electrostatic charge?). I'm not sure if SiC would carry any sort of a
> charge that would help. I doubt it.
>
> I forget the mechanism of action of Veegum T and CMC. One, no doubt,
> is more suitable.
>
CMC is a high molecular weight organic molecule
that swells up in water like a tiny sponge. Put
enough CMC in your glaze and it will turn into
a jelly-like consistency that should hold anything
in suspension.
Of course being organic it is also prone to rot so
I wouldn't mix up a 5 gallon batch.
earl...
Ben Morrison on sat 28 apr 12
I'm pretty sure that the Veegum T would disrupt the copper red glaze entire=
=3D
ly.=3D0A=3D0A=3D0A-Ben=3D0A=3D0A=3D0A=3D0A________________________________=
=3D0A From: Rober=3D
t Harris =3D0ATo: Clayart@LSV.CERAMICS.ORG =3D0ASe=
nt: =3D
Saturday, April 28, 2012 3:34 PM=3D0ASubject: Re: Tom Turner's electric red=
.=3D
=3D0A =3D0AHmmm possibly. I know I have Veegum T, not sure if I've got any =
CMC =3D
at=3D0Athe moment. Perhaps lurking somewhere.=3D0A=3D0AI do know that I wou=
ld wan=3D
t a suspending agent that will work with=3D0Ahigh density grains, and (I'm =
as=3D
suming) is not dependent on clays=3D0A(electrostatic charge?). I'm not sure=
i=3D
f SiC would carry any sort of a=3D0Acharge that would help. I doubt it.=3D0=
A=3D0A=3D
I forget the mechanism of action of Veegum T and CMC. One, no doubt,=3D0Ais=
m=3D
ore suitable.=3D0A=3D0AI think that is a Ron Roy question - Ron, any though=
ts?=3D
=3D0A=3D0ARobert=3D0A=3D0A=3D0A=3D0AOn Sat, Apr 28, 2012 at 3:53 PM, Url Kr=
ueger ueger@gmail.com> wrote:=3D0A> Robert,=3D0A>=3D0A> How about using CMC as a =
suspen=3D
ding agent?=3D0A>=3D0A> earl in Oregon=3D0A> Impatiently waiting to see wha=
t's in=3D
=3D0A> Oregon Potters Association Showcase=3D0A> next week. =3DA0Y'all come=
.=3D0A=3D
=3D0A=3D0A=3D0A-- =3D0A----------------------------------------------------=
------
Robert Harris on sat 28 apr 12
My initial response to Ben was rejected by the liserv. Here is another try.
OK. Why (or perhaps a better question is how), do you think Veegum T
would disrupt the Copper Red entirely.
I have to admit that having read around the subject even more, it
seems likely that adding hydrochloric acid as a flocculent (affecting
the Gerstley Borate rather than the (mostly absent) clays), would be a
better approach.
Robert
>
> On Sat, Apr 28, 2012 at 8:30 PM, Ben Morrison wrote=
:
>> I'm pretty sure that the Veegum T would disrupt the copper red glaze
>> entirely.
>>
>>
William & Susan Schran User on sun 29 apr 12
On 4/28/12 9:38 PM, "pdp1@EARTHLINK.NET" wrote:
>Yes...I would think...get the 1500 grit.,,or even finer if possible.
>Or, get solid Tungsten Carbide 'Balls' for the solid Tungsten Carbide
>Cannister Ball Mill...and Mill it down fine as Cigarette Ash.
>Does anyone Calcine these ingredients first?
>Or would it matter if one did?
Wouldn't think calcining the materials would be necessary, except if zinc
is a component, then that should be calcined, but only to 1200F.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Robert Harris on sun 29 apr 12
I do have a couple of hypothetical technical questions on SiC.
One of the things that everyone seems to agree on is that copper reds
need to be reduced early. General consensus in the archives is ^010.
Do we know at what temperature SiC is likely to reduce CuO (CuCO3
decomposes at 290C to CuO). My guess is that it is a lot hotter than
cone 10.
Is there another reducing agent that is active at a lower temperature?
One thing I have considered using is graphite. There were a couple of
mentions in the archives of "rumours" of people using graphite. I did
a bit of online research and this isn;t quite as silly as it sounds.
Graphite does not start to oxidize until about 450C (850F) and even
then the rate of oxidation is slower than you might think. So it might
hang around long enough to be useful.
Unfortunately carbon isn't a particularly good reducing agent. In
blast furnaces (and reduction kilns) the main, most powerful reducing
agent is Carbon Monoxide, and I don't know if this would be produced,
even at the local level, in an electric kiln.
There is also the usual negatives to having carbon around anyway
(Black Coring - although I'm using a grolleg porcelain), etc etc.
So any other thoughts on a lower temperature reducing agent? Or at
what temp SiC starts to reduce?
Thanks
Robert
On Sun, Apr 29, 2012 at 9:01 AM, William & Susan Schran User
wrote:
> On 4/28/12 9:38 PM, "pdp1@EARTHLINK.NET" wrote:
>
>>Yes...I would think...get the 1500 grit.,,or even finer if possible.
>>Or, get solid Tungsten Carbide 'Balls' for the solid Tungsten Carbide
>>Cannister Ball Mill...and Mill it down fine as Cigarette Ash.
>>Does anyone Calcine these ingredients first?
>>Or would it matter if one did?
>
> Wouldn't think calcining the materials would be necessary, except if zinc
> is a component, then that should be calcined, but only to 1200F.
>
> Bill
> --
> William "Bill" Schran
> wschran@cox.net
> wschran@nvcc.edu
> http://www.creativecreekartisans.com
--
----------------------------------------------------------
Robert Harris on sun 29 apr 12
On Sun, Apr 29, 2012 at 10:50 AM, Robert Harris w=
rote:
> Do we know at what temperature SiC is likely to reduce CuO (CuCO3
> decomposes at 290C to CuO). My guess is that it is a lot hotter than
> cone 10.
Ooops, I meant ^010 of course.
Eva Gallagher on sun 29 apr 12
Hi - Something that I read somewhere a few years ago is that the silicon
carbide needs to be incredibly fine - someting like 20.000 mesh if I
remember correctly. I have tried with regular Si from ceramic distributor
and never got anything good.
Glad to be back on Clayart - somehow got delisted a few weeks ago and for a
while I thought that Clayart was down again.
Eva Gallagher
Deep River, Ontario
http://newfoundoutpotter.blogspot.com/
----- Original Message -----
From: "Robert Harris"
To:
Sent: Sunday, April 29, 2012 10:50 AM
Subject: Re: Tom Turner's electric red.
>I do have a couple of hypothetical technical questions on SiC.
>
> One of the things that everyone seems to agree on is that copper reds
> need to be reduced early. General consensus in the archives is ^010.
>
> Do we know at what temperature SiC is likely to reduce CuO (CuCO3
> decomposes at 290C to CuO). My guess is that it is a lot hotter than
> cone 10.
>
> Is there another reducing agent that is active at a lower temperature?
>
> One thing I have considered using is graphite. There were a couple of
> mentions in the archives of "rumours" of people using graphite. I did
> a bit of online research and this isn;t quite as silly as it sounds.
> Graphite does not start to oxidize until about 450C (850F) and even
> then the rate of oxidation is slower than you might think. So it might
> hang around long enough to be useful.
>
> Unfortunately carbon isn't a particularly good reducing agent. In
> blast furnaces (and reduction kilns) the main, most powerful reducing
> agent is Carbon Monoxide, and I don't know if this would be produced,
> even at the local level, in an electric kiln.
>
> There is also the usual negatives to having carbon around anyway
> (Black Coring - although I'm using a grolleg porcelain), etc etc.
>
> So any other thoughts on a lower temperature reducing agent? Or at
> what temp SiC starts to reduce?
>
> Thanks
>
> Robert
>
> On Sun, Apr 29, 2012 at 9:01 AM, William & Susan Schran User
> wrote:
>> On 4/28/12 9:38 PM, "pdp1@EARTHLINK.NET" wrote:
>>
>>>Yes...I would think...get the 1500 grit.,,or even finer if possible.
>>>Or, get solid Tungsten Carbide 'Balls' for the solid Tungsten Carbide
>>>Cannister Ball Mill...and Mill it down fine as Cigarette Ash.
>>>Does anyone Calcine these ingredients first?
>>>Or would it matter if one did?
>>
>> Wouldn't think calcining the materials would be necessary, except if zin=
c
>> is a component, then that should be calcined, but only to 1200F.
>>
>> Bill
>> --
>> William "Bill" Schran
>> wschran@cox.net
>> wschran@nvcc.edu
>> http://www.creativecreekartisans.com
>
>
>
> --
> ----------------------------------------------------------
>
>
Steve Slatin on sun 29 apr 12
Robert -- Harding Black did a piece in the Feb 2002 Ceramics Monthly.=3D0A=
=3DA0=3D
=3D0AHe refers to Baggs and Littlefields' Journal of the ACS article of May=
, =3D
1932,=3D0ABlack doesn't deal with most of these questions, but he does repo=
rt=3D
=3D0Asuccess at ^06, using SiC, so I'd tend to the belief that's enough hea=
t=3D
=3D0Ato disassociate SiC.=3D0A=3DA0=3D0AOnce the SiC has disassociated, my =
understa=3D
nding is that the reduction=3D0Ais a chemical reaction, and not a heat-driv=
en=3D
one.=3DA0 That is consistent with=3D0ASiC being used successfully for redu=
ctio=3D
n at ^06, 6, 8, and 9.=3D0A=3DA0=3D0AThis is wholly speculative, but I'd gu=
ess th=3D
at the reason why painting =3D0ASiC on top of a copper glaze doesn't give r=
ed=3D
is that the SiC disassociates=3D0Aand generated CO in atmosphere, giving i=
mm=3D
ediate CO2.=3D0A=3DA0=3D0AThose gas bubbles in the glaze I cracked open sho=
w that=3D
they remain within=3D0Athe glaze for sufficient time to get to ^6, hold, a=
nd=3D
do a slow cool.=3DA0 That would=3D0Aput the CO within the body of the glaz=
e wh=3D
ere it can react with the copper.=3D0A=3DA0=3D0AThe Baggs and Littlefield a=
rticle=3D
was reprinted by ACS, so you'll probably need=3D0Aa library ID to get it o=
n =3D
line.=3DA0 They do deal with some of the questions that=3D0Ayou're interest=
ed i=3D
n, though, like putting the SiC in the slip.=3D0A=3DA0=3D0AJust my two kopi=
--=3D0A=3D
=3D0ASteve Slatin=3DA0 =3D0A=3D0A=3D0AN48.0886450=3D0AW123.1420482 =3D0A=3D=
0A=3D0A----- Origi=3D
nal Message -----=3D0AFrom: Robert Harris =3D0ATo:=
Cla=3D
yart@LSV.CERAMICS.ORG=3D0ACc: =3D0ASent: Sunday, April 29, 2012 9:50 AM=3D0=
ASubje=3D
ct: Re: Tom Turner's electric red.=3D0A=3D0AI do have a couple of hypotheti=
cal =3D
technical questions on SiC.=3D0A=3D0AOne of the things that everyone seems =
to a=3D
gree on is that copper reds=3D0Aneed to be reduced early. General consensus=
i=3D
n the archives is ^010.=3D0A=3D0ADo we know at what temperature SiC is like=
ly t=3D
o reduce CuO (CuCO3=3D0Adecomposes at 290C to CuO). My guess is that it is =
a =3D
lot hotter than=3D0Acone 10.=3D0A=3D0AIs there another reducing agent that =
is act=3D
ive at a lower temperature?=3D0A=3D0AOne thing I have considered using is g=
raph=3D
ite. There were a couple of=3D0Amentions in the archives of "rumours" of pe=
op=3D
le using graphite.
Steve Slatin on sun 29 apr 12
Lou -- Sorry, Ceramic Society.
Steve Slatin --
N48.0886450
W123.1420482
----- Original Message -----
From: L TURNER
To: Steve Slatin
Cc:
Sent: Sunday, April 29, 2012 8:21 PM
Subject: Re: Tom Turner's electric red.
Is this a journal article in Journal of American Ceramic Society or in
Journal of American Chemistry Society?
Lou Turner,
ivor and olive lewis on mon 30 apr 12
Dear Robert Harris.
Are you reducing Black copper oxide to Red Copper oxide or to elemental
Colloidal Copper
If you lay out balanced equations for potential reactions between Silicon
Carbide and Black Copper oxide it is a simple matter to substitute values
for the Heats of Formation (kJ per Mol) for the reactants and products, d=
o
the sums and draw the conclusions.
You can also calculate the temperature at which this is likely to happen.
Regards,
Ivor Lewis,
REDHILL,
South Australia
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