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raw vs high fired raku?

updated thu 2 dec 10

 

Cathi Newlin on sun 28 nov 10


I did a search of the archives and found one post, but wanted a little
more input if you have a moment...

Typically I do single-fired cone 10 reduction ware.
Eliminating the bisque firing has really worked well for me in terms of
energy consumption, glaze fit, etc. I have to do 2 cone 10 firings this
week to get ready for a show/sale next Sat.
One of the things I whipped up were some ornaments.
I will probably glaze and fire some in the next 2 firings, but I thought
it would be nice to raku a few of them also.

I have 2 choices, as I see it...#1 is to fire all the ornaments to cone
10 and then go back and raku some of them, and #2 is to raw fire Raku them.
One extreme or the other as it were.
These are simple little one-piece slabs - nothing fancy - but I think a
good white crackle on them will make them kinda special.

Anyone have any thoughts on which way they would go and why?
Thanks. Hope everyone has had a great holiday!

--
Cathi Newlin, Angels Camp, Ca
box49@caltel.com
http://www.cnewlin.com

paul gerhold on mon 29 nov 10


Cathi,
If your work is vitreous at cone 10 firing to this point and then doing a
Raku firing will most probably result in broken pieces from the thermal
shock. You will stand a better chance doing the Raku firing with raw glaze=
d
pieces although I wouldn't give it a great probability of success.

Paul

James Freeman on mon 29 nov 10


On Sun, Nov 28, 2010 at 1:47 PM, Cathi Newlin wrote:

> I have 2 choices, as I see it...#1 is to fire all the ornaments to cone
> 10 and then go back and raku some of them, and #2 is to raw fire Raku the=
=3D
m.
> One extreme or the other as it were.



Cathi...

Dittos to what Paul said. I would offer two additional possibilities:

Bisque fire the pieces you intend to raku in your raku kiln, just
going slower than for a glaze firing.

High fire the pieces with a cone 10 crackle glaze, then rub india ink
or dye into the crackle.

Good luck.

...James

James Freeman

"All I say is by way of discourse, and nothing by way of advice.=3DA0 I
should not speak so boldly if it were my due to be believed."
-Michel de Montaigne

http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources

L TURNER on mon 29 nov 10


Cathi

Robin Hopper, when asked a firing/glazing question, responded: T.I.A.S
(Try It And See).

I can only add: evaluate the risks.

1. The original raku work was done with greenware in a wood/charcoal
kilns - (& yes the potter had an coarse and open clay body.) Just
fire the green pieces in your raku kiln very slow - i.e. bisque fire
in the raku kiln. Make sure the ware is DRY before you start. Allow
some time for burnout and sintering. In other words the raku firing
of greenware will take a lot longer than a regular raku firing.
Be patient.

2. Firing to cone 10 followed with a raku firing is no different than
firing to cone 10 and followed by a china paint firing. If the china
painters can do it so can you. (just don't use the R word around the
pots and the pots will never know the difference).


2.a. The cone 10 fired ware will be non-porous so you will have to
modify your glaze medium to get it to stick to the pot when you apply
it. I have successfully used both Elmer's glue and acrylic medium to
hold the glaze on to the pot. Just make a thick batch of glaze and
add the glue or acrylic to thin the glaze you are going to put on the
pot. Let it dry thoroughly before you put it in the kiln.

2.b. Being non-porous, the cone 10 fired ware will not pick up much
black soot when in the reduction chamber, so the crackle lines might
not be as visible as with lowfired raku. The reduction should work
just fine on the glaze however.


Regards,

L. Turner
The Woodlands, TX

Cathi Newlin

paul gerhold on tue 30 nov 10


I am not at all sure that a Raku firing is similar to a china paint firing.
Do you really remove pieces at 800-900 degrees and then put them into
combustable material in a china paint firing. Seems to me the thermal shoc=
k
will be totally different.

Paul

Lee Love on wed 1 dec 10


You could put the "raku" pieces at the top of the kiln and then pull
only those at what ever temp. Close, and fire the regular cone 10.
Or, if you do hikidashi, you'd pull the pieces near the end of the
firing.

One altermative could be to saggar fire some of the work at the same
time as cone 10.

In my wood kiln, I have put refires in the ashpit below the
grates and got some wonderful yohen (changing chamber) effects,
similar to putting charcoal in the kiln at the end of the firing.

Try! Experiment! Test!

On Sun, Nov 28, 2010 at 12:47 PM, Cathi Newlin wrote:
> I did a search of the archives and found one post, but wanted a little
> more input if you have a moment...
>
> Typically I do single-fired cone 10 reduction ware.
> Eliminating the bisque firing has really worked well for me in terms of
> energy consumption, glaze fit, etc. I have to do 2 cone 10 firings this
> week to get ready for a show/sale next Sat.
> One of the things I whipped up were some ornaments.
> I will probably glaze and fire some in the next 2 firings, but I thought
> it would be nice to raku a few of them also.
>
> I have 2 choices, as I see it...#1 is to fire all the ornaments to cone
> 10 and then go back and raku some of them, and #2 is to raw fire Raku the=
=3D
m.
> One extreme or the other as it were.
> These are simple little one-piece slabs - nothing fancy - but I think a
> good white crackle on them will make them kinda special.
>
> Anyone have any thoughts on which way they would go and why?
> Thanks. Hope everyone has had a great holiday!
>
> --
> Cathi Newlin, Angels Camp, Ca
> box49@caltel.com
> http://www.cnewlin.com
>



--=3D20
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/

=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi