Marcia Selsor on mon 1 oct 01
Dear Gene.
I use this glaze often. For the best colors.. fire to 1850. Because it is dry you
can't judge by the surface if firing by eye.
Put into straw or paper for reduction quicker than a crackle glaze.. Give it some
air after a minute or so to let the combustion material reignite. Then close until
cool..
Marcia Selsor, Profoessor Emeritus Montana State University Billings
Arnolds Home Improvements wrote:
> Hello all !!!
>
> This weekend I plan to attempt to do my first raku firing using a copper
> based glaze. The glaze I have chosen is one I found in the question column
> of this months ceramics monthly, it is as follows.
>
> New Dry Alligator
>
> bone ash 28.57%
> gerstley borate 57.14
> nep. syenite 14.29
>
> cobalt carb. 1.43%
> copper carb. 5.00
> manganese dioxide 1.43
>
> now for the question
>
> I have done raku white crackle but never copper.
>
> Is there a special way to do reduction in order to get the best colors?
>
> Do you put these in water or let then cool in the reduction?
>
> Do copper glazes go directly into reduction or set out a little like the
> crackle glazes?
>
> Thanks in advance for any help !!!!!!!!!!!!
>
> Gene Arnold
> mudduck@advi.net
> Playing in the mud in N.C.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
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>
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Arnolds Home Improvements on mon 1 oct 01
Hello all !!!
This weekend I plan to attempt to do my first raku firing using a copper
based glaze. The glaze I have chosen is one I found in the question column
of this months ceramics monthly, it is as follows.
New Dry Alligator
bone ash 28.57%
gerstley borate 57.14
nep. syenite 14.29
cobalt carb. 1.43%
copper carb. 5.00
manganese dioxide 1.43
now for the question
I have done raku white crackle but never copper.
Is there a special way to do reduction in order to get the best colors?
Do you put these in water or let then cool in the reduction?
Do copper glazes go directly into reduction or set out a little like the
crackle glazes?
Thanks in advance for any help !!!!!!!!!!!!
Gene Arnold
mudduck@advi.net
Playing in the mud in N.C.
Dannon Rhudy on mon 1 oct 01
>New Dry Alligator
This alligator glaze is very similar to one
the students use here. My experience
is that the quicker you get it into the
reducing chamber, the more colorful it will
be. The longer it is out in the air, the
more green/blue it will be.
Keep in mind that such glazes often fade
as the copper oxidizes later.
regards
Dannon Rhudy
Lamar, Luke on tue 2 oct 01
Hi Gene,
In addition to getting the pieces into the reduction chamber quickly, I also
reduce in the kiln. Five to ten minutes to the completion of the firing, I
reduce the air intake and cover the hole (with fiber) in the top of the kiln
halfway. The last ten to 15 seconds of the firing I completely cover the
hole - you will see flames come out of the burner port. I have always gotten
beautiful coppers this way (luck??). Also, don't open your reduction
chamber too quickly - copper might disappear.
With regard to Marcia's comments on judging when pots are done... I have a
glossy copper glaze (Radcliff Apple Green) that matures at about the same
temperature as my matte copper glazes. I always have at least one Apple
Green piece visible through the peephole as a witness piece.
Good luck with your firing!
Luke Lamar
llamar@bacweb.org
-----Original Message-----
From: Arnolds Home Improvements [mailto:mudduck@ADVI.NET]
Sent: Monday, October 01, 2001 8:04 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: copper raku
Hello all !!!
This weekend I plan to attempt to do my first raku firing using a copper
based glaze. The glaze I have chosen is one I found in the question column
of this months ceramics monthly, it is as follows.
New Dry Alligator
bone ash 28.57%
gerstley borate 57.14
nep. syenite 14.29
cobalt carb. 1.43%
copper carb. 5.00
manganese dioxide 1.43
now for the question
I have done raku white crackle but never copper.
Is there a special way to do reduction in order to get the best colors?
Do you put these in water or let then cool in the reduction?
Do copper glazes go directly into reduction or set out a little like the
crackle glazes?
Thanks in advance for any help !!!!!!!!!!!!
Gene Arnold
mudduck@advi.net
Playing in the mud in N.C.
____________________________________________________________________________
__
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.
Arnolds Home Improvements on sun 14 oct 01
Thanks to all that responded to my post on reducing copper raku!!!
I did my first copper raku firing this weekend (have done crackle but this
was my first copper matte). Got some great colors!!
Is there something that can be applied to the pots to keep the colors from
fading over time?
What is the best method to clean the pots after reduction and cooling? Do
you scrub them like crackle or is there something else?
Is there a recipe that will give great colors but with a shine instead of
matte?
Gene Arnold
mudduck@advi.net
Playing in the mud in N.C.
james w. thomas on tue 16 oct 01
Hello Gene,
I,ve been experimenting with a high gloss copper raku glaze for about two years now.
The original was given to me by Steve Ochs at Southern Arkansas University where I took my first clay class. His recipe was titled BLACK MAGIC
80 Colemanite
20 Custer Feldspar this gives a beautiful clear crackle
to this add
10 copper carb.
5 red iron oxide
1 cobalt carb.
This gives a glaze that matures at about 1780 F
My own revised version of this glaze is J2 Black Magic
80 Laguna borate
20 Custer Feldspar
20 Copper carb.
10 Red Iron Oxide
2 Cobalt carb.
This glaze matures around 1900 to 2000 F. I fire Raku by site instead of a pyrometer. I let the kiln soak for 5 minutes or so then turn the gas down slightly to allow for a more comfortable pull from the kiln. I know that one day the colors will start changing but so for in two years there has been no noticeable change. (I tell every customer that the colors may change in time)If you leave the ware buried in damp saw dust over night or at least until it cools below 1000 F you will get a very brilliant copper gloss.
I also like to scoop out a hole in the saw dust and lay in a thin layer of newspaper to keep the saw dust from imprinting the glaze. I clean up with comet and a sponge or bristle brush but this will take your colors away if you rub too hard.
Have fun, I have.
Soon to have a website up I hope within the next 2 to 3 weeks we are waiting for a high speed digital line to be installed.
Get your FREE download of MSN Explorer at http://explorer.msn.com
BobWicks@AOL.COM on tue 16 oct 01
Hi Lamar:
If you make your formula to meet the limit for SiO2 in your copper Raku
formula you will find that it eliminates the so called change in color over
time. You can check this out with Tony on the INSIGHT Web Site.
BOB
Lamar, Luke on tue 16 oct 01
Hi Gene,
>Is there something that can be applied to the pots to keep the
>colors from fading over time?
I have tried using a matte, acrylic spray. It works, but it will change the
appearance of the glaze - not the colors, just the surface texture and
shine.
>What is the best method to clean the pots after reduction and
>cooling? Do you scrub them like crackle or is there something else?
For my copper mattes, I use a dry, stiff brush like a fingernail brush. I
try to brush off excess ash only.
>Is there a recipe that will give great colors but with a shine
>instead of matte?
Copper Penny (recipe follows) produces a moderately shiny copper surface
under heavy reduction and a moderately shiny dark green brown (ugly IMHO) in
oxidation. I have seen it produce rainbow like colors, but I haven't been
too successful at getting this effect.
Copper Penny Recipe
Feldspar - 38
Gerstley Borate - 62
Add:
Copper Carbonate - 7.7
Red Iron Oxide - 3.8
My absolute favorite, shiny raku glaze is Radcliffe Apple Green (recipe
follows). In oxidation this glaze produces a beautiful blue/green color. In
moderate reduction it produces blue/green with copper patches and an overall
copper sheen. In heavy reduction it produces fantastic copper (not rainbow,
just copper), blue/green patches, and sometimes red/maroon patches. Thin
applications of the glaze over a white clay body yields a whitish, speckled
blue color. I always get something I like with this glaze.
Radcliffe Apple Green Recipe
Frit 3134 - 90
EPK - 10
Add:
Copper Carbonate - 4
Tin Oxide - 5
Bentonite - 2
Epsom Salts - 1
Glaze is very powdery, so I recommend applying it by pouring or dipping, not
painting. My last batch came out somewhat opaque. Add less Epsom salts
maybe??
If you use this glaze I would like to know how it works for you. Also, if
you come across any other shiny raku glazes let me know. Thanks.
Luke Lamar
llamar@bacweb.org
Carolyn Bronowski on wed 17 oct 01
Hi--this is for Bob. What is the INSIGHT web side and who is Tony. Thank
you Carolyn
> -----Original Message-----
> From: BobWicks@AOL.COM [SMTP:BobWicks@AOL.COM]
> Sent: Tuesday, October 16, 2001 7:47 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: copper raku
>
> Hi Lamar:
> If you make your formula to meet the limit for SiO2 in your copper Raku
> formula you will find that it eliminates the so called change in color
> over
> time. You can check this out with Tony on the INSIGHT Web Site.
>
> BOB
>
> __________________________________________________________________________
> ____
> 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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