Dave Finkelnburg on sun 28 may 06
Dear Claydance,
It would be polite, it seems to me, if you would
identify yourself.
Rob makes his living from that glaze, has invested
major time in developing it, so I won't comment on the
ingredients in it. If I knew that he had published
the recipe, that would be different. Perhaps he will
tell you.
What Rob has done is made a glaze that crawls in a
controlled fashion. It is a very high shrinkage
glaze--shrinkage between wet and fired--so it shrinks
a lot as it gets heated and begins to melt. It is
also a very viscous glaze, so when it melts it doesn't
run.
A crazed glaze melts in the firing and then cracks
on cooling due to thermal expansion mismatch with the
body it's applied to. Rob's glaze is really made
differently.
Regards,
Dave Finkelnburg, thinking about "Decoration
Day," as it used to be called, this last Monday in May
here in the US, and about so many who deserve our
gratitude for their sacrifices...
--- claydance wrote:
> Robert Sutherland Jr. has a pot on page 52 of
> American Craft June/July 2006.
> Does anyone have a clue about how to get that
> surface effect?
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claydance on sun 28 may 06
Robert Sutherland Jr. has a pot on page 52 of American Craft June/July =
2006. It is called Two Necked Vase and has the most incredible white =
crackle pattern I have ever seen. It has a smooth, three dimensional =
type of surface where the crackle lines are indented, but not black. The =
areas in between the lines protrude in a "pillowy" pattern .
Does anyone have a clue about how to get that surface effect? I have =
done white crackle in oxidation, and that forms a flat glassy mechanical =
looking crackle. I have done white crackle in raku, and that produces an =
organic type of pattern, but not pillowy, and shows black where the =
glaze crackles.
I desperately need a clue. I have 2 year old bisqued pots waiting for =
the perfect "skin". I'm doing cone 6 porcelain and my pieces are very =
thin, "liquid" looking (or attempted), and all curves.
Even a theory at this point would be more than I have now.
Des & Jan Howard on mon 29 may 06
Claydance
Identify yourself & you'll get an answer, promise.
Des
claydance wrote:
>Robert Sutherland Jr. has a pot on page 52 of American Craft June/July 2006. It is called Two Necked Vase and has the most incredible white crackle pattern I have ever seen. It has a smooth, three dimensional type of surface where the crackle lines are indented, but not black. The areas in between the lines protrude in a "pillowy" pattern .
>
>Does anyone have a clue about how to get that surface effect? I have done white crackle in oxidation, and that forms a flat glassy mechanical looking crackle. I have done white crackle in raku, and that produces an organic type of pattern, but not pillowy, and shows black where the glaze crackles.
>
>I desperately need a clue. I have 2 year old bisqued pots waiting for the perfect "skin". I'm doing cone 6 porcelain and my pieces are very thin, "liquid" looking (or attempted), and all curves.
>
>Even a theory at this point would be more than I have now.
>
>
--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
claydance on mon 29 may 06
Dave,
I am Vicki Gardner in College Station, Texas. I'm so happy to be on this
fantastic listserve. Hi everybody!
Rob's surfaces are definitely unique and identifyable, and I certainly
wouldn't want an exact duplication. However, a pillow like breakup of a
glaze is worth exploring and I am guessing may have many variations. I think
you have given me the direction I needed. The only theory I knew was the
expansion mismatch and cracking upon cooling. But what you are saying (I
think) is that there is an alternative - the glaze forms a pattern when it
melts even before it cools.
Personal info:
- My daytime job is a multimedia designer
- Summer hobby is sand sculpting
- My passion is clay. 5 years experience, local classes and workshops. I
have a converted garage with electric wheel and electric kiln. Kids are off
to college and I have time to create when I'm not working overtime.
Thanks for the tip
Vicki Gardner (Claydance)
----- Original Message -----
From: "Dave Finkelnburg"
To:
Sent: Monday, May 29, 2006 12:45 AM
Subject: Re: Glaze on Robert Sutherland Jr. pot in American Craft
> Dear Claydance,
> It would be polite, it seems to me, if you would
> identify yourself.
> Rob makes his living from that glaze, has invested
> major time in developing it, so I won't comment on the
> ingredients in it. If I knew that he had published
> the recipe, that would be different. Perhaps he will
> tell you.
> What Rob has done is made a glaze that crawls in a
> controlled fashion. It is a very high shrinkage
> glaze--shrinkage between wet and fired--so it shrinks
> a lot as it gets heated and begins to melt. It is
> also a very viscous glaze, so when it melts it doesn't
> run.
> A crazed glaze melts in the firing and then cracks
> on cooling due to thermal expansion mismatch with the
> body it's applied to. Rob's glaze is really made
> differently.
> Regards,
> Dave Finkelnburg, thinking about "Decoration
> Day," as it used to be called, this last Monday in May
> here in the US, and about so many who deserve our
> gratitude for their sacrifices...
>
> --- claydance wrote:
>> Robert Sutherland Jr. has a pot on page 52 of
>> American Craft June/July 2006.
>> Does anyone have a clue about how to get that
>> surface effect?
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>
> ______________________________________________________________________________
> 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.
>
John Post on tue 30 may 06
Hi Vicki,
I haven't seen the pot you are talking about in the magazine but from
your description it sounds like a glaze that is high in magnesium
carbonate. This is the light fluffy powder chemical. If you add enough
to a glaze it will make the glaze crack when drying (sometimes it even
falls off as it dries). Black underglaze is probably applied to the pot
first. Then the pot is either dipped or sprayed with glaze containing
the magnesium carbonate.
The reason these glazes can be tricky is that if you get them too thick,
they crack and fall off. If you don't apply them thick enough, they
don't crack on the pot as the glaze dries. It is best to load and fire
pots glazed in this type of glaze immediately after you glaze them. If
you let them sit around on a shelf there are more chances for the glaze
to fall off.
I believe that Lana Wilson's book has a few recipes for these types of
glazes in it. And if you check in the archives for the words "Ball
Crawl" or beaded, beading texture glazes, you might come up with
something to get you started.
John Post
Sterling Heights, Michigan
claydance on tue 30 may 06
Thanks, John
The Lana Wilson lead helped me a lot, especially in relation to heavily
applied engobes containing borax. Now it's making sense how a pattern can be
so varied because of chunks actually falling off inbetween drying and
firing.
Vicki Gardner
College Station, TX
----- Original Message -----
From: "John Post"
To:
Sent: Tuesday, May 30, 2006 3:40 PM
Subject: Re: Glaze on Robert Sutherland Jr. pot in American Craft
> Hi Vicki,
>
> I haven't seen the pot you are talking about in the magazine but from
> your description it sounds like a glaze that is high in magnesium
> carbonate. This is the light fluffy powder chemical. If you add enough
> to a glaze it will make the glaze crack when drying (sometimes it even
> falls off as it dries). Black underglaze is probably applied to the pot
> first. Then the pot is either dipped or sprayed with glaze containing
> the magnesium carbonate.
>
> The reason these glazes can be tricky is that if you get them too thick,
> they crack and fall off. If you don't apply them thick enough, they
> don't crack on the pot as the glaze dries. It is best to load and fire
> pots glazed in this type of glaze immediately after you glaze them. If
> you let them sit around on a shelf there are more chances for the glaze
> to fall off.
>
> I believe that Lana Wilson's book has a few recipes for these types of
> glazes in it. And if you check in the archives for the words "Ball
> Crawl" or beaded, beading texture glazes, you might come up with
> something to get you started.
>
> John Post
> Sterling Heights, Michigan
>
> ______________________________________________________________________________
> 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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