rick mace on tue 6 jun 00
Waterproof Raku? Well, here are some ideas to play with for not just making
your Raku waterproof but also for having it keep it's copper luster colors.
I use this "copper sand revised #1" (formula below) It came from an article
in Ceramic Review Issue #159, May/June 1996. I believe Tom Buck cooked this
up (and wrote the article) to meet the problem of Raku losing it's color. I
have a piece I used it on three years ago and it still looks good. Most of
the Raku on my web page is this glaze and I think you will find it worth
looking at. If you do (look at my page) you will also notice that I call
many pieces "Raku Stoneware." That brings me to waterproofing.
When I first returned to pottery making after 20 years away, I was
introduced to Raku. But there were so many complaints about it's not being
strong or holding water. I decided to try raising the bisque temperature
and, using different cone 10 clays, bisqued them to cone 4 to 6 (not 06 to
04). That darn near makes it waterproof right there, and together with Tom's
revised copper sand, you've got waterproof Raku as Tom's glaze forms a glass
surface.
The problem is, you really have to baby the pieces in the cooling to keep
them from cracking as the near stoneware temperature bisque makes them very
"not happy" when cooled quickly, and they will crack.
So now, again if you are looking at my web page, you will find many of what
I've called "Puzzle Pieces." I hate to lose work and that "stoneware
bisque" did in many large pieces at Raku (small pieces make it through
pretty well, I even Raku fired a piece that had been previously cone 10
glaze fired and it worked). I would take my beautifully colored, but cracked
"Raku Stoneware" pieces and club them with a fat stick until I had many
small pieces. Then, being very very careful not to lose any pieces, I packed
newspaper around them and then set the newspaper on fire (isn't fire fun!).
That smoked the edges and changed the character quite a bit. Also, I would
keep out the brightest pieces from the fire (so that they would not be
smoked or changed). Then I put the whole works back together (puzzle pieces)
with Elmer's glue (duct tape helps). When that dries, you can wash the extra
glue off with water and the color is not effected as it is with most glues
which seem to destroy the color and basically make a mess. Then I'd mix some
Elmer's glue with any black powder to make a filler for any missing chips.
Then scrub it again. Then, when it's dry, I paint them with poly urethane
(probably didn't spell that right) and ... well ... take a look! And have
fun making waterproof Raku; be it stoneware-atized or poly urethane-ated.
Rick
Rick Mace Pottery
http://www.panworld.net/~rmace
Copper Sand Revised #1 (thanks Tom Buck)
Gerstley borate- 32
Borax (decahydrate)-30
Bone ash-11
Flint-18.5
Grolleg Kaolin-8.5
Copper carb - 5
Cobalt oxide - 2.5
CNW on wed 7 jun 00
Rick- I have done some of the puzzle pieces simliar to what you described. I
do sculptural work though.
I had to do something since I got too excited and opened the kiln when it
was was too hot. Then I knew what the term "dunting" meant.
I mashed them a little more then I pit-fired the broken pieces then glued
them. On one of the pieces I went the extra step of softening the edges by
rubbing them on the driveway. Made it a little harder to get a true fit but
it looked good. As a matter of fact one of my instructors and his wife have
that piece. Makes me smile when I visit.
Celia in NC
cwike@conninc.com
rick mace on wed 7 jun 00
To add to what I posted yesterday (copied below). It is very important to
pull out the work very hot. We used garbage cans lined with wet paper at the
top to make a nice seal. Then after 5 or 6 minutes we opened the top just
for a second or two. That really makes the colors develope.
Some of my web pictures were not loading correctly, but that should be fixed
now.
Rick
http://www.panworld.net/~rmace
>From yesterday:
Waterproof Raku? Well, here are some ideas to play with for not just making
your Raku waterproof but also for having it keep it's copper luster colors.
I use this "copper sand revised #1" (formula below) It came from an article
in Ceramic Review Issue #159, May/June 1996. I believe Tom Buck cooked this
up (and wrote the article) to meet the problem of Raku losing it's color. I
have a piece I used it on three years ago and it still looks good. Most of
the Raku on my web page is this glaze and I think you will find it worth
looking at. If you do (look at my page) you will also notice that I call
many pieces "Raku Stoneware." That brings me to waterproofing.
When I first returned to pottery making after 20 years away, I was
introduced to Raku. But there were so many complaints about it's not being
strong or holding water. I decided to try raising the bisque temperature
and, using different cone 10 clays, bisqued them to cone 4 to 6 (not 06 to
04). That darn near makes it waterproof right there, and together with Tom's
revised copper sand, you've got waterproof Raku as Tom's glaze forms a glass
surface.
The problem is, you really have to baby the pieces in the cooling to keep
them from cracking as the near stoneware temperature bisque makes them very
"not happy" when cooled quickly, and they will crack.
So now, again if you are looking at my web page, you will find many of what
I've called "Puzzle Pieces." I hate to lose work and that "stoneware
bisque" did in many large pieces at Raku (small pieces make it through
pretty well, I even Raku fired a piece that had been previously cone 10
glaze fired and it worked). I would take my beautifully colored, but cracked
"Raku Stoneware" pieces and club them with a fat stick until I had many
small pieces. Then, being very very careful not to lose any pieces, I packed
newspaper around them and then set the newspaper on fire (isn't fire fun!).
That smoked the edges and changed the character quite a bit. Also, I would
keep out the brightest pieces from the fire (so that they would not be
smoked or changed). Then I put the whole works back together (puzzle pieces)
with Elmer's glue (duct tape helps). When that dries, you can wash the extra
glue off with water and the color is not effected as it is with most glues
which seem to destroy the color and basically make a mess. Then I'd mix some
Elmer's glue with any black powder to make a filler for any missing chips.
Then scrub it again. Then, when it's dry, I paint them with poly urethane
(probably didn't spell that right) and ... well ... take a look! And have
fun making waterproof Raku; be it stoneware-atized or poly urethane-ated.
Rick
Rick Mace Pottery
http://www.panworld.net/~rmace
Copper Sand Revised #1 (thanks Tom Buck)
Gerstley borate- 32
Borax (decahydrate)-30
Bone ash-11
Flint-18.5
Grolleg Kaolin-8.5
Copper carb - 5
Cobalt oxide - 2.5
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