raku with lusters - john martin
DESCRIPTION
The Golden TouchEnhancing raku with lustersby John Martin“Raku Floral Form,” 11”x19”x7”. Thrown and assembled with applied vitreous slip texture, colored slips and lusters applied at various stages. Multiple firings ending with raku post-firing reduction.There’s a renaissance in raku occurring with the advancements and availability of new colors. New technologies have allowed the potter to buy ready-to-use pre-made colors. Stains and gold lusters have become a more consistent and durableTRANSCRIPT
PotteryMaking Illustrated • January/February 2007 15
There’s a renaissance in raku occurring with the advancements and availability of new colors. New technologies have allowed the potter to buy ready-to-use pre-made colors.
Stains and gold lusters have become a more consis-tent and durable means of infusing a surface with saturated color. Different stains can be mixed togeth-er just like mixing paint. This allows a potter to have an unlimited palette rich in color, while maintaining the atmospheric quality and crackle of raku.
With commercial lusters, the glazed form records the memory of the fire. Gold luster flashes in the raku reduction, extending its range of character while cre-ating beautiful transitions of color that reflect light. The real secret to using lusters effectively is know-
The Golden TouchEnhancing raku with lusters
by John Martin
ing how to develop the glazed and unglazed surfaces underneath.
By building up the surface quality with vitreous slips, copper accents and glossy glaze the harmony of the gold is balanced by the opportunity for spon-taneous variation.
The lusters are applied outdoors with an airbrush using both red and yellow gold. The vessel is then fired in an outdoor electric kiln to cone 019. After cooling, a thin coat of opal is applied. The thin wash of opal creates a rainbow of color, so a light over-spray in areas enhances the flash of the fire.
The final firing at cone 021 is sufficient red heat to create an intersection of carbon transfer, good crack-le, copper flash and gold flash.
“Raku Floral Form,” 11”x19”x7”. Thrown and assembled with applied vitreous slip texture, colored slips and lusters applied at various stages. Multiple firings ending with raku post-firing reduction.
16 PotteryMaking Illustrated • January/February 2007
1To get a heavily textured surface, I apply slip to the outside of a freshly thrown
form. The slip should be thick enough to create a variey of textures without running.
2 Use a torch to dry the slip until it’s no longer shiny and
starts to crackle. The crackle is enhanced by stretching the clay using a wooden rib on the inside.
3 After the clay reaches leather hard, construc-
tion is completed. Here I’ve taken a cylinder, cut it in half, attached it to the sides and added caps.
4 After bisque firing to cone 04, pour glaze into the piece and work quickly to roll it around.
Rotate the piece as you pour out the glaze to evenly coat the rim.
5 To highlight the texture, brush on White Crackle glaze over the vitreous slip. Next, sponge away
the surface to leave glaze in the low areas and cracks.
6 White glaze is applied with a slip trailer and bamboo brush, then I begin to add colors, often
overlapping up to five coats. Slip trailing white over the pattern adds even more movement.
7 Copper accents are brushed onto the unglazed areas and the vitreous slip. Splatter more white
glaze over the exterior using a scrubbing brush and fire to cone 06.
PotteryMaking Illustrated • January/February 2007 17
WARNING: When spraying lusters, it is very important to
use a NIOSH/MSHA approved respirator with an organic vapor cartridge that blocks or removes vapors. I use an in-line air hood that delivers
fresh air through a hose.
8 Apply liquid N-Gold luster with an airbrush over the copper accents, then apply Gold 170 over
remaining areas of slip stopping just below the edge of the glazed surface.
9 Fire the piece to cone 019, then spray the lusters with a thin coat of Opal.
Fill a can halfway with
dry sawdust then line the perimeter with newsprint. Fire the piece to cone 021 and remove it hot. Light the paper and place the piece into a metal trash can of burning sawdust and news-print. The preheated environment reduces thermal shock and unnecessary cracking.
Pour in more sawdust and add more newsprint to establish a
blazing fire and add to the insulation in the cooling period.
10
11 Detail showing effects of crackled surface, multiple colored glazes and lusters after post-firing reduction.12
18 PotteryMaking Illustrated • January/February 2007
Golden Touch Recipes
Vitreous Stretch SlipFerro Frit 3134 . . . . . . . . . . . . . . . . . 30 %EPK Kaolin . . . . . . . . . . . . . . . . . . . . 70 100 %
Shiny White CrackleCone 06
Ferro Frit 3134 . . . . . . . . . . . . . . . . . 70 %EPK kaolin . . . . . . . . . . . . . . . . . . . . 30 100 %
Add: Gum . . . . . . . . . . . . . . . . . . . . 2 %To get intense colors, add 30% of the following stains to this glaze . All the stains are Mason stains unless otherwise noted .
6121 Saturn Orange 6129 Golden Ambrosia 6207 Tangerine 6343 Mediterranean Blue 6378 Cerulean Blue 6381 Blackberry Wine 6404 Vanadium Yellow 6319 Lavender Bordeaux Red 44769 (Cerdec) Intense Red 44768 (Cerdec)
Copper AccentCone 06
Copper Carbonate . . . . . . . . . . . . . . 70 %Borax . . . . . . . . . . . . . . . . . . . . . . . 30 100 %
Add: Gum . . . . . . . . . . . . . . . . . . . . 3 %
JadeCone 06
Ferro Frit 3134 . . . . . . . . . . . . . . . . . 70 %EPK Kaolin . . . . . . . . . . . . . . . . . . . . 30 100 %
Add:Copper Carbonate . . . . . . . . . . 2 %Gum . . . . . . . . . . . . . . . . . . . . . . . . 2 %
LustersEngelhard N-Gold: Fire to cone 019Engelhard Luster Gold 170: Fire to cone 019Engelhard Opal 850: Final firing at Cone 021
John Martin received his BFA from Western Kentucky University and an MFA from Southern Illinois University. John is a studio pot-ter in Berea, Kentucky, where he’s also an instructor at the Kentucky School of Craft. For comments or questions, contact John at [email protected].
GREAT LAKESCLAY & SUPPLY COMPANY
120 S Lincoln Avenue Carpentersville, Illinois 60110
800-258-8796 Fax 847-551-1083www.GreatClay.com
email [email protected]
CALL US FOR MOREINFORMATION
Introducing the
*Weighs under 45 pounds and can center 50+ pounds of clay!*Complete - Includes stool, Versa-BatTM, three bats, splash pan.*Stackable - Reclaim valuable workshop or classroom space.*Portable - Easily carry it to throwing demos or workshops.*Internal storage - For buckets, bats, tools or clay.*Reversible - With the flip of a switch.
-- NN -- GGOO TM!! (Patent Pending)TThhrrooww