I've moved to my own site: sheamores.com
Join me there for new posts on ceramic techniques for beginners, by a beginner. I'm currently navigating the commercial glaze jungle...come on over and see if I survive or if the wild glaze beasts devour me whole!
Friday, September 13, 2013
Friday, June 14, 2013
Stain / Antique Effect on Greenware using Underglaze
Here’s another technique that uses commercial underglazes, staining aka antique effect.
My staining video (click the Youtube icon to open a new window and view larger):
Supplies:
-Leather hard clay tile and/or pendants cut from 1/4” thick slab, cleaned up and prepped (hole or wire in pendant).
-Incising tools such as Kempers ball-tipped tools, wire stylus, or a pencil will do. You can use just about any blunt-tipped tool for incision.
-Commercial underglaze, any color (in contrast to clay color works best)
-Small container to mix underglaze with water
-Brushes to paint on stain, in size appropriate to the piece.
-Metal rib
Step 1:
Incise a design into leather-hard pieces (tile or pendants in my case). The lines need to be deep enough to hold the stain during the scrape-back step; 1/32” to 1/16” seems to hold the color well. The design can be freehand or an image that you download, print, and then transfer onto the moist clay by laying it down and then rubbing over it gently with a damp sponge. The laser ink will transfer to the clay to give you guidelines for incision, and then burn off in the first firing.
Step 2:
Allow the incised piece to dry to bone-dry stage. This may take a day or two depending on how thick/large your piece is.
Step 3:
In a small container, mix underglaze and water at an approximately 50:50 ratio. The underglaze will be thinner than milk; a very watery consistency.
Step 4:
Brush the stain over the bone-dry pieces. The stain will absorb into the clay immediately. To avoid over-saturating the clay with liquid, brush the stain on in rather quick strokes. Just one coat will do.
Step 5:
Use the straight edge of a metal rib to gently begin scraping back the stain, revealing the incised design below. I usually start at the center and work my way out, rotating the piece as I go.
Step 6: Bisque fire (I’m using earthenware so I bisque to cone 04)
Step 7: Glaze fire (mine are at cone 05). I used Amaco clear and Duncan Envsion transparent colored glazes for the demo pieces (Grape and Peacock).
I use underglazes for this technique, but Mason Stains may also be used. Here is a PDF from Georgie’s for using Mason Stains, with recipes.
It’s also possible to apply this technique to bisque that has some texture to it. Stain it the same way as greenware, but instead of using a metal rib to scrape back the excess, use a newspaper or damp sponge. The first layer of glaze is sponged on to keep the stain from smearing; some people fire their pieces in between the underglaze/stain application and the glaze application to avoid smearing.
And that wraps up the techniques for this slab! My next post will be about bisque and glaze firing in a computer-controlled test kiln. The controller makes basic cone firings very simple, just a couple of button presses and it’s ready to go.
After that, I’m deciding which techniques to cover in my next slab series...for now I’m leaning towards slip trailing, glaze scraping, and wax resist, but that may change by the time I get around to filming it.
Thanks for joining me, I hope that you’ll come back for the next slab. In the meantime, get your hands in some clay and start making those wonderful creations that have been knocking around inside your head for awhile now...you can do it!
Sunday, May 19, 2013
Sgraffito Technique
The next decorating technique that I’ll be demonstrating is sgraffito (which roughly means ‘scratch’ in Italian). It’s fairly straightforward and easy to do once you get a feel for when the best time to scratch through the underglaze is. Often times people make their own slips or underglazes (which are both quite similar in makeup) from their own formulas. Here is an underglaze formula from Vince Pitelka, and a decorating slip formula from Big Ceramic Store, if you’re interested in mixing your own batches.
I’ve used Amaco’s LUG (Liquid Underglaze) and Velvets series, both of which can be used on greenware or bisque. Spectrum’s 500 series can also be used on both. Duncan Concepts are for bisque only and so won’t work for this type of sgraffito. Make sure that the brand you pick can be used on greenware. Any color of underglaze may be used but in terms of contrast, naturally, dark underglaze will look better on light colored clay and light underglaze will look better on dark clay.
Here are pics of the three pendants I applied this technique to in the video:
The top photo is after a Cone 04 bisque firing, and the bottom are the finished pendants after a Cone 05 glaze firing.
My Sgraffito Video, showing how these pendants were made and brought to completion (you'll be better off clicking the 'YouTube' icon on the video to watch it at their site, I can't seem to get the video to appear larger here):
Supply List:
--Cheese- to Leather-hard clay; rolled out, cut, cleaned and prepped with hole/wire as desired.
--Small brushes with long bristles. I bought a set of mop brushes that had a couple with 1/4” to 1/2” wide brush heads.
--Duster brush to sweep away debris. I use an old blush/powder brush with sable bristles.
--Sgraffito tools: In the video I use the Kemper DBS and DBSS ball-tipped tools, the WLS wire stylus and the WS wire stylus. Many different tools can be used instead, including dental tools, a pencil, quill, skewer, pin tool, about anything with a fine tip will work.
-Underglaze, prepared, any color, shaken and stirred well
-Magnification headset, optional, helps when scratching fine details if your eyesight is weak
-Latex gloves as a precaution
Step 1: Dampen a brush with water and then load up with underglaze. You’ll get a feel for how much liquid to pick up on your brush after you’ve done a few pieces. The brush I use takes in too much for the small area of a pendant, so I wipe one side of the brush against the side of the container to get rid of half of it before brushing.
I try and brush in only one direction, but this usually leaves one edge with too much underglaze piling up, so I’ll brush it at an angle in the opposite direction to help even it out. You’re going for a smooth, even coat, without stirring up a lot of clay. The underglaze can get muddy-looking if the brush moves too much clay around, so try and minimize the number of strokes while keeping the coat even.
One coat is usually sufficient to cover the clay well. If you see the clay through the underglaze, it will probably need another coat.
For an interesting effect, a coat of one color may be brushed on, left to dry, and then a second coat of another color applied over the first. When you scratch through using varying pressure on the tool, some of the first layer’s color will remain if the lines are not too deep to reach the clay. This method works better when the piece has dried to bone dry. Either apply the underglaze when the piece is bone dry or let an underglazed piece go to bone dry.
The underglaze that I use (Velvets and LUG) may be applied at any greenware stage, from wet to bone dry, as well as to bisque. When brushed on wet stage clay, the underglaze stays like finger paints for awhile and dries very slowly. When brushed on cheese to leather hard stage and left to dry, the underglaze and clay are soft and it is easy to achieve fine lines and carving effects. When applied to bone dry stage clay, the underglaze and clay are both like compressed powder; designs may still be scratched through, but when lines intersect the space between the lines tends to flake off. I usually save my less detailed designs for bone dry sgraffito. You’ll find your own preference for which stage works best for your type of designs.
Step 2: Wait for the underglaze to dry. The color will lighten slightly and will no longer feel cool to the touch when it’s dry. Sometimes it helps to turn off the bright overhead light if you’re using one in order to see if there are damp parts still left on a piece (the shadows are clearer in dimmer light).
Step 3: You can start scratching through the underglaze with a fine-tipped tool freehand as I did in the video, or for more complex designs you can use a stencil or cutout to lightly trace the main outline of the design with a pin tool or other suitable instrument, and then add the finer details after removing the stencil. For larger areas of underglaze removal, I use the Kemper WS wire stylus, and for wider lines I use the WLS stylus.
Step 4: After the design is complete, the piece is left to dry for 3-4 days, depending on the humidity level. I usually keep the boards full of finished pieces covered lightly with a sheet of bubble wrap. It slows down the drying to keep warpage to a minimum.
Step 6: The pendants and tile are then bisque fired to Cone 04 using the Fast Bisque cone-fire setting on the computer controller of my electric test kiln.
Step 7: I brushed three coats of Amaco LG-10 clear to the black and white pendant and the tile, and two coats of Duncan Envision Peacock on the pendant with green lines, and Duncan Envision Grape on the purple pendant.
Step 8: The pendants and tile were then fired to Cone 05 using the Slow Glaze cone-fire program.
That’s about all there is to it, a pretty easy technique, eh? Next time I’ll be demo’ing Staining, as seen in the bottom right group of pendants here and the upper half of the tile:
Until then, may your hands be ever so muddy...have fun!
I’ve used Amaco’s LUG (Liquid Underglaze) and Velvets series, both of which can be used on greenware or bisque. Spectrum’s 500 series can also be used on both. Duncan Concepts are for bisque only and so won’t work for this type of sgraffito. Make sure that the brand you pick can be used on greenware. Any color of underglaze may be used but in terms of contrast, naturally, dark underglaze will look better on light colored clay and light underglaze will look better on dark clay.
Here are pics of the three pendants I applied this technique to in the video:
The top photo is after a Cone 04 bisque firing, and the bottom are the finished pendants after a Cone 05 glaze firing.
My Sgraffito Video, showing how these pendants were made and brought to completion (you'll be better off clicking the 'YouTube' icon on the video to watch it at their site, I can't seem to get the video to appear larger here):
Supply List:
--Cheese- to Leather-hard clay; rolled out, cut, cleaned and prepped with hole/wire as desired.
--Small brushes with long bristles. I bought a set of mop brushes that had a couple with 1/4” to 1/2” wide brush heads.
--Duster brush to sweep away debris. I use an old blush/powder brush with sable bristles.
--Sgraffito tools: In the video I use the Kemper DBS and DBSS ball-tipped tools, the WLS wire stylus and the WS wire stylus. Many different tools can be used instead, including dental tools, a pencil, quill, skewer, pin tool, about anything with a fine tip will work.
-Underglaze, prepared, any color, shaken and stirred well
-Magnification headset, optional, helps when scratching fine details if your eyesight is weak
-Latex gloves as a precaution
Step 1: Dampen a brush with water and then load up with underglaze. You’ll get a feel for how much liquid to pick up on your brush after you’ve done a few pieces. The brush I use takes in too much for the small area of a pendant, so I wipe one side of the brush against the side of the container to get rid of half of it before brushing.
I try and brush in only one direction, but this usually leaves one edge with too much underglaze piling up, so I’ll brush it at an angle in the opposite direction to help even it out. You’re going for a smooth, even coat, without stirring up a lot of clay. The underglaze can get muddy-looking if the brush moves too much clay around, so try and minimize the number of strokes while keeping the coat even.
One coat is usually sufficient to cover the clay well. If you see the clay through the underglaze, it will probably need another coat.
For an interesting effect, a coat of one color may be brushed on, left to dry, and then a second coat of another color applied over the first. When you scratch through using varying pressure on the tool, some of the first layer’s color will remain if the lines are not too deep to reach the clay. This method works better when the piece has dried to bone dry. Either apply the underglaze when the piece is bone dry or let an underglazed piece go to bone dry.
The underglaze that I use (Velvets and LUG) may be applied at any greenware stage, from wet to bone dry, as well as to bisque. When brushed on wet stage clay, the underglaze stays like finger paints for awhile and dries very slowly. When brushed on cheese to leather hard stage and left to dry, the underglaze and clay are soft and it is easy to achieve fine lines and carving effects. When applied to bone dry stage clay, the underglaze and clay are both like compressed powder; designs may still be scratched through, but when lines intersect the space between the lines tends to flake off. I usually save my less detailed designs for bone dry sgraffito. You’ll find your own preference for which stage works best for your type of designs.
Step 2: Wait for the underglaze to dry. The color will lighten slightly and will no longer feel cool to the touch when it’s dry. Sometimes it helps to turn off the bright overhead light if you’re using one in order to see if there are damp parts still left on a piece (the shadows are clearer in dimmer light).
Step 3: You can start scratching through the underglaze with a fine-tipped tool freehand as I did in the video, or for more complex designs you can use a stencil or cutout to lightly trace the main outline of the design with a pin tool or other suitable instrument, and then add the finer details after removing the stencil. For larger areas of underglaze removal, I use the Kemper WS wire stylus, and for wider lines I use the WLS stylus.
Step 4: After the design is complete, the piece is left to dry for 3-4 days, depending on the humidity level. I usually keep the boards full of finished pieces covered lightly with a sheet of bubble wrap. It slows down the drying to keep warpage to a minimum.
Step 6: The pendants and tile are then bisque fired to Cone 04 using the Fast Bisque cone-fire setting on the computer controller of my electric test kiln.
Step 7: I brushed three coats of Amaco LG-10 clear to the black and white pendant and the tile, and two coats of Duncan Envision Peacock on the pendant with green lines, and Duncan Envision Grape on the purple pendant.
Step 8: The pendants and tile were then fired to Cone 05 using the Slow Glaze cone-fire program.
That’s about all there is to it, a pretty easy technique, eh? Next time I’ll be demo’ing Staining, as seen in the bottom right group of pendants here and the upper half of the tile:
Until then, may your hands be ever so muddy...have fun!
Wednesday, May 1, 2013
Making Bisque Stamps for Impressing Into Clay
Stamped impressions are an easy way to add a raised image to the clay surface, and give the ability to produce multiple pieces with the same design fairly quickly. Stamps, rollers, texture mats, and found objects are all tools used to impress a design onto clay. Here are a couple of photos of the pendants I stamped in the last video:
The first pic is the raw clay after stamping and cleanup, the 2nd & 3rd is after bisque firing to Cone 04, and the last is after brushing on 3 coats of colored transparent glaze (Duncan Envision Clear Black and Grape) and firing again, this time to Cone 06, along with the bisque stamps that made the impressions at the raw clay stage.
I used bisque stamps for these pendants, but there are many options when it comes to impressing texture/designs into clay.
Where do you find the tools for clay impression? You could (A)make your own, (B)use found objects such as plants and shells, or (C)buy commercially made stamps/tools.
(A) Make Your Own
Make your own stamps, rollers and texture mats out of clay and then bisque fire (tutorial below with links to other tutorials); or carve into plaster, wood, linoleum, polymer or air-dry clay. The principal is the same with all of these materials: incise/carve a design into a flat face on the material (or with soft material like clay you can use found objects instead of incising--see ‘found objects’ below), fire it to bisque or cure it as necessary (polymer/air dry clay); it is then pressed into moist clay, leaving a positive/raised impression of the design on the clay. The design you incise/carve/impress on the stamp face should be no more than 1/16” inch deep, or else it will later make it hard to impress the deepest recesses of the stamp design without deforming the clay it’s being pressed into.
I make bisque stamp discs which are initially cut from a 1/4” thick slab of leather-hard low-fire white clay. Alternatively, you could slice pieces off of a coil or use a small ball of clay with a flattened face to hold the design.
Tutorial/Video: Making and Using Clay Bisque Stamps:
Step 1: Use a cutter to remove a circle from a rolled out slab of leather-hard clay. I use the same cutter that I use to cut out pendants (the bisque stamp will be slightly smaller than a raw clay cutout because of shrinkage in the bisque), or a cutter that is slightly smaller than my pendant cutter. Because I use a round cutter, a circle will be part of the impression left on wet clay. If I want a triangular impression with no circle as a background, I would cut the entire stamp into a triangle so that it would be the only shape comprising the background.
Step 2: Using wire, loop and/or ball-tipped tools, outline and then incise your design onto the top face of the clay cutout to no deeper than 1/16”. Use a soft brush (I use a makeup/powder brush) to swipe away the loose clay bits but while incising, try not to worry too much about the burrs and leftover clay along the lines. As the clay dries, these will be easier to brush away and the lines can be gone over again and smoothed over with you finger, a wood tool, or a barely damp sponge or soft, short-bristled brush (I use an eyeshadow brush for this).
If you’re not sure what to carve and/or don’t want to draw freehand, try Googling ‘black and white outline’, ‘silouhette’ or something similar to see some stock drawings. Download one that you like, or draw your own and then size it in Adobe Illustrator or other drawing application, print it up and transfer the image to the wet to leather-hard slab by slightly wetting the slab with a sponge and then lightly burnishing the printout onto the slab. This will leave an inked image on the slab (which burns off in the firing); you’ll then be able to easily see where your cutout and incision/carving lines are. These are the completed stamps in the video, and the impressions that they leave. Normally I would cut out the clay pendant shapes first, and then stamp them.
Other Blogs Demonstrating How To Make Stamps, Rollers, and Texture Mats for Clay:
Nancy Gallagher Pottery: Making Bisque Stamps and Texture Mats
Ceramic Arts Daily: Making Polymer Clay Texture Stamps
Tara Robertson/My Pottery Blog: Bisque Stamps
Ceramic Arts Daily: Making a Bisque Texture Mat with Fresh Flowers
B) Found Objects: Instead of using found objects to make bisque stamps as above, impress them directly onto the clay surface with each piece. That is, you’re using the object to make the impression each time you make a tile/pendant/whatever instead of using a stamp made out of an impression of the object. The design won’t be raised like a stamped design is, of course. You can use things like netting, lace, buttons, wallpaper, shells, wood, plants...anything with a nice texture or relief will work. Thrift shops and flea markets offer good opportunities to pick up some old buttons, etc.
C) Commercial Sources, here's a few to get you started:
Lisa Pavelka: Silicone Stamps and Texture Mats
ClayStamps on Etsy: Bisque rollers and stamps
MKM Wood Stamps at Big Ceramics Store
Xiem Clay Rollers at Bailey Pottery
Plaster Texture Molds at Dogwood Ceramics
Art Clay World USA: Rubber Stamps and Texture Mats.
Stampin.com: Rubber Stamps
Inkadinkado: Rubber Stamps
Above, I've used a commercially made wood stamps, leaves, shells, and stamps made of carved plaster and air-dry clay to leave impressions in the slab.
How to Use Impressing Tools:
Stamps: Apply equal pressure to the stamp as it is pressed into the clay. If the stamp is composed of non-porous material such as rubber, silicone, linoleum or polymer/air-dry clay, it is best to dust the stamp with a small amount of a release agent such as cornstarch before impressing.
Rollers: Roll over the slab before cutting out pendants/tile, or if cut out clay is still wet enough may be able to roll after cutting out.
Texture Mats: You’ll want to transfer the slab to the texture mat and then roll over the top of the slab with a rolling pin, with the texture mat underneath
Found Objects: Use a pastry/flower roller to press plants into the clay, other objects will take experimenting with, usually just press it in and see what you get!
Here's a pic of the finished pieces I'll be demonstrating the surface treatments for in upcoming videos:
The tile has sgraffito and staining, the stamped/impressed pendants for this post are in the upper right, the stained pendants are in the lower right and the sgraffito pendants are in the lower left. I'll be going over how each of these decorating techniques works as well as bisque firing, glazing, and glaze firing. Thanks for reading/viewing, and for now it's back to the slab! Have fun out there playing in the clay now...
The first pic is the raw clay after stamping and cleanup, the 2nd & 3rd is after bisque firing to Cone 04, and the last is after brushing on 3 coats of colored transparent glaze (Duncan Envision Clear Black and Grape) and firing again, this time to Cone 06, along with the bisque stamps that made the impressions at the raw clay stage.
I used bisque stamps for these pendants, but there are many options when it comes to impressing texture/designs into clay.
Where do you find the tools for clay impression? You could (A)make your own, (B)use found objects such as plants and shells, or (C)buy commercially made stamps/tools.
(A) Make Your Own
Make your own stamps, rollers and texture mats out of clay and then bisque fire (tutorial below with links to other tutorials); or carve into plaster, wood, linoleum, polymer or air-dry clay. The principal is the same with all of these materials: incise/carve a design into a flat face on the material (or with soft material like clay you can use found objects instead of incising--see ‘found objects’ below), fire it to bisque or cure it as necessary (polymer/air dry clay); it is then pressed into moist clay, leaving a positive/raised impression of the design on the clay. The design you incise/carve/impress on the stamp face should be no more than 1/16” inch deep, or else it will later make it hard to impress the deepest recesses of the stamp design without deforming the clay it’s being pressed into.
I make bisque stamp discs which are initially cut from a 1/4” thick slab of leather-hard low-fire white clay. Alternatively, you could slice pieces off of a coil or use a small ball of clay with a flattened face to hold the design.
Tutorial/Video: Making and Using Clay Bisque Stamps:
Step 1: Use a cutter to remove a circle from a rolled out slab of leather-hard clay. I use the same cutter that I use to cut out pendants (the bisque stamp will be slightly smaller than a raw clay cutout because of shrinkage in the bisque), or a cutter that is slightly smaller than my pendant cutter. Because I use a round cutter, a circle will be part of the impression left on wet clay. If I want a triangular impression with no circle as a background, I would cut the entire stamp into a triangle so that it would be the only shape comprising the background.
Step 2: Using wire, loop and/or ball-tipped tools, outline and then incise your design onto the top face of the clay cutout to no deeper than 1/16”. Use a soft brush (I use a makeup/powder brush) to swipe away the loose clay bits but while incising, try not to worry too much about the burrs and leftover clay along the lines. As the clay dries, these will be easier to brush away and the lines can be gone over again and smoothed over with you finger, a wood tool, or a barely damp sponge or soft, short-bristled brush (I use an eyeshadow brush for this).
If you’re not sure what to carve and/or don’t want to draw freehand, try Googling ‘black and white outline’, ‘silouhette’ or something similar to see some stock drawings. Download one that you like, or draw your own and then size it in Adobe Illustrator or other drawing application, print it up and transfer the image to the wet to leather-hard slab by slightly wetting the slab with a sponge and then lightly burnishing the printout onto the slab. This will leave an inked image on the slab (which burns off in the firing); you’ll then be able to easily see where your cutout and incision/carving lines are. These are the completed stamps in the video, and the impressions that they leave. Normally I would cut out the clay pendant shapes first, and then stamp them.
Other Blogs Demonstrating How To Make Stamps, Rollers, and Texture Mats for Clay:
Nancy Gallagher Pottery: Making Bisque Stamps and Texture Mats
Ceramic Arts Daily: Making Polymer Clay Texture Stamps
Tara Robertson/My Pottery Blog: Bisque Stamps
Ceramic Arts Daily: Making a Bisque Texture Mat with Fresh Flowers
B) Found Objects: Instead of using found objects to make bisque stamps as above, impress them directly onto the clay surface with each piece. That is, you’re using the object to make the impression each time you make a tile/pendant/whatever instead of using a stamp made out of an impression of the object. The design won’t be raised like a stamped design is, of course. You can use things like netting, lace, buttons, wallpaper, shells, wood, plants...anything with a nice texture or relief will work. Thrift shops and flea markets offer good opportunities to pick up some old buttons, etc.
C) Commercial Sources, here's a few to get you started:
Lisa Pavelka: Silicone Stamps and Texture Mats
ClayStamps on Etsy: Bisque rollers and stamps
MKM Wood Stamps at Big Ceramics Store
Xiem Clay Rollers at Bailey Pottery
Plaster Texture Molds at Dogwood Ceramics
Art Clay World USA: Rubber Stamps and Texture Mats.
Stampin.com: Rubber Stamps
Inkadinkado: Rubber Stamps
Above, I've used a commercially made wood stamps, leaves, shells, and stamps made of carved plaster and air-dry clay to leave impressions in the slab.
How to Use Impressing Tools:
Stamps: Apply equal pressure to the stamp as it is pressed into the clay. If the stamp is composed of non-porous material such as rubber, silicone, linoleum or polymer/air-dry clay, it is best to dust the stamp with a small amount of a release agent such as cornstarch before impressing.
Rollers: Roll over the slab before cutting out pendants/tile, or if cut out clay is still wet enough may be able to roll after cutting out.
Texture Mats: You’ll want to transfer the slab to the texture mat and then roll over the top of the slab with a rolling pin, with the texture mat underneath
Found Objects: Use a pastry/flower roller to press plants into the clay, other objects will take experimenting with, usually just press it in and see what you get!
Here's a pic of the finished pieces I'll be demonstrating the surface treatments for in upcoming videos:
Tuesday, April 16, 2013
Cutting Out, Cleanup and Prep of Small Clay Tile and Pendants
Slab #1 / Video #2
So now I’ve rolled out a slab, what’s next?
I’ll need the clay to vary from leather-hard on some pieces to bone dry on others in order to best apply the surface treatments I’ve chosen for the pieces I’m making out of this slab. There are other techniques that work better when the clay is still at wet-stage, such as adding sprigs and joining pieces for additive high relief, slip trailing/brushing, and adding impressions/texture to the slab, but I won’t be using any of those on these pieces (with the exception of stamp impression, which can be done at wet or leather-hard stage with a hard-surface stamp such as bisque, wood, or plaster).
-To test if a slab is leather-hard, I try gently moving the slab by pushing opposing corners, without forcing it. When it pulls away from the board and moves easily, it’s ready to cut out.
Here's a photo of the pieces where they are right now, ready for bisque firing. I'll point out real quickly which decorating techniques I'll be demonstrating in upcoming videos, and then I'll let you get on to the Cutting Out/Prep video:
Blue Circle: incised circles to bisque into stamps; Yellow: pendants with stamp impressions; Red: Incised, stained, and scraped back pendants; Green: Pendants with sgraffito ('scratch') through underglaze; Pink: tile with sgraffito and stain. These will be bisque fired this week and I'll update the photo in my next post of how they are progressing. I'll begin the decorating videos next time with how to make and use bisque stamps and found objects to impress images, patterns and texture into clay.
Cutting out, cleanup and prep of clay tiles and pendants Video:
Supply List:
-Rolled slab of clay, dried to leather-hard stage
-Sponge/small bucket of clean water
-Pin Tool, Xacto knife, or fettling knife (for cutting clay)
-Ware board approx. 1 sq. ft. plywood, fiber board, masonite, wallboard or other hard porous work surface
-Small pastry roller (optional)
(1) Template method:
-Cereal carton or cardboard box (to make template out of)
-Scissors or Xacto knife (cutting out template)
(2) Shape Cutter method:
-Shape cutters (I mainly use these plastic ones and sometimes these Kemper rose cutters on thinner slabs
-Cornstarch
Pendant prep supplies:
-Ball-tipped tool (Kemper BSL) or Wooden skewer, even a large needle or small quill works (for drilling holes)
OR
-High Temperature Wire (other gauges available, I use 24 gauge but it is very light, like Xmas ornament wire)
-Wire cutters
-Small pliers
(other gauges available, I use 24 gauge but it is very light, like Xmas ornament wire)
Method 1: Using a Template
Step 1: Make a template by first measuring/drawing the size & shape you want your tile to be onto a flat carton or piece of cardboard (you’ll likely need a power saw for making a plywood cutout). For measuring squares/rectangles I use a framing square, a compass for circles, triangles for angles, etc.). Cut the shape out of the carton using scissors or an Xacto knife (the scissors are much easier to use on beverage/cereal cartons, the Xacto is easier on corrugated cardboard).
Step 2: Place the template on the slab and begin making the cuts along the edge of the template, always drawing the blade towards you when cutting while holding the template firmly in place. Keep the blade/pin tool straight up and down as you cut or at a very slight outward facing angle. Make all of the cuts and then remove the template.
Step 3: Soften each tile’s corners (they tend to be the first part of the tile to dry out and crumble if left at a sharp angle) by cutting a tiny piece off at a slight angle and then gently rounding and pushing them in with your fingers. When the tiles are firm enough to pick up (past the stage of bending easily), gently soften the edges of the tile with your pin tool, a wood tool, or your finger and then run and blot a clean, barely damp sponge over the edges and the rest of the tile.
-Step 4: See **’Drying Method’ below
Method (2): Using cutters to cut out shapes:
Step 1: Rub a little cornstarch between your fingers and then run your fingers over the sides of the cutter (this is only necessary on the cutters without the release plunger).
Step 2: Push the cutter straight down with even pressure into the clay. Hold the surrounding slab down as you pull the cutter out. The cut piece will likely be in the cutter instead of having remained on the slab. Apply firm pressure to an edge or two of the clay from the top of the cutter to push it out onto the work board. Once the piece has released from the cutter, gently pat down the piece to flat again if it has bent out of the cutter. Using a flower/pastry roller helps to flatten the tile again.
Step 3: See **Drying Method below
The following steps are for Pendant prep (drilling holes or placing high temp wire):
-I work on one pendant at a time, taking it from under the bag leaving the others covered. If I’m going to be stamping a raised image onto the front face, I press the image in before drilling the the stringing hole or inserting the high temperature wire.
a) High Temp Wire: High temperature wire can be purchased from a ceramic supplier and is useful when you want to eliminate a hole in your pendant. Using it instead of a hole also makes glazing prep and clean up a lot faster, is easier to fire, and provides a built in ring for attaching the finished pendant easily to a cord or jump ring.
Step 1: Prepare the wire loops before cutting out your pendants. I make a bunch at a time and store them for later use. Make a loop by bending a short (approx. 2”) length of the wire in half, and then wrapping one end of the wire around the other end. Keep the end that is being wrapped in a straight line with the hoop while the other end is twisted around it.
Step 2: Lightly squeeze both faces of the pendant on either side of the place you’ll be inserting the wire. Push the twisted end of the wire straight into the side of the pendant; your other fingers will be able to help guide the wire and keep it from splitting through the face. It’s better to keep the end towards the back face of the pendant so that if it burns through a bit in the firing it won’t affect the front face.
-Once the wire is in place, try not to move it around or hold the piece by the wire. After it’s bisque fired, you’ll be able to hold the piece (for glazing and such) by the wire without it coming loose. I’ve really tugged on them, trying to pry them loose after bisque firing, but they’re in there for the duration. You will however still be able to twist the loop after firing, so you don’t have to worry about facing the loop forward or sideways before firing. A thicker gauge of wire than I’m using (24 gauge) may not be as flexible after firing.
b) Drilling a Hole through the pendant instead of using high temp wire: Place an index finger on the side of the pendant, just above where you’ll be drilling the hole. This will help prevent the top side from cracking through if you make the hole too close to the top edge. With the pendant face-up and flat on the board, push a ball-tipped tool straight from the front to the back. Pick up the pendant and clean the clay from the exposed tool on the back before pulling it through to the front again. Level the area around the hole and pass the tool through the clay again, towards the front this time. These same steps are taken when using a wooden skewer instead of a tool. Dampen the end of the skewer with water before turning it in circles while at the same time pushing it through the clay.
**Drying Method for all Cut Pieces: After cleaning up the tiles/pendants, I place them back on the work board. They are now ready to decorate, or I’ll cover the whole board/tiles with a plastic bag if I’ll be away a few hours. If away from the pieces for more than a couple of hours, I’ll cover the board itself with a plastic bag, then lay the tiles on the plastic-covered board, and then cover the whole thing with yet another plastic bag. Spraying a fine water mist into the bag every once in a while helps slow down drying. The pieces can be kept almost indefinitely this way, until you’re ready to work on them. When they are then decorated, you’ll want to dry your pieces slowly and evenly by keeping them under plastic and exposing them once in a while to air, and then turning them over and covering them again, and repeating for a couple of days. Slower, even drying will help prevent warpage.
----------------------------------
Added Notes on Templates: Can be made from just about any material from paper to cereal cartons, corrugated cardboard, or a piece of plywood if you’re going to be cutting many multiples of the same size and shape and need the template to last a long time. In the video I’m making a 2” square template from a cereal carton and using it as a template to cut out a single tile. You may want to utilize a rectangular shaped template for cutting up a whole slab at one time.
To give you an idea how that works, here’s a Ceramic Arts Daily video with Angelica Pozo who shows how to use rectangular templates from masonite for cutting up larger groups of tiles:
Templates can be used for cutting out at any stage of clay dryness between wet to leather-hard. Unless I’m attaching pieces (sprigs) to wet clay, I usually wait until leather-hard for cut-out; it leaves cleaner, more workable edges. Wet clay is very easy to tear and smoosh so more care has to be taken when cutting it.
Added Notes on Using Shape Cutters: I usually use this method for smaller pieces like pendants, but I also use them quite often in cutting out tiles as well. The two sets of cutters I use are a) 3/4”H plastic cutters, which vary from 1.5” to 5.5” squares, circles, hexes, ovals, stars and hearts; and Kemper’s rose cutter set, which are 1/4”H circles that vary from 1/2” to 2” in diameter. This last set has a plunger release feature which ejects the piece of clay from the cutter, but they don’t work well on slabs over 1/8” thick; the plunger also leaves a circular impression on the pendant face. I usually use this set for circular pendants that I’ll be stamping, using the impression left by the cutter as a guideline for my stamp.
You can also use cookie or pastry cutters, available from gourmet and chef suppliers. Tile cutters for making larger, standard sized (4.25” and 6”) tiles are available from ceramic suppliers, these have spring loaded releases to keep the tile flat on the board at all times. They cost around $50.
It’s best to wait until the slab is at the firmer stages to use cutters as they tend to stick and bend the clay more when used in wet stage clay.
--------------------------------
Added Notes on Other Forming and Shape Cutting Methods Not Included in Video:
There are several other ways to make tile and pendant forms from clay that don’t always involve slabs such as small push molds, coils (for beads and jewelry), slip casting, and extrusion…the first two I’ve used and will eventually make videos for, but I haven’t tried the last two yet.
One last method that I use quite a bit but again didn’t cover in this video is the use of computer printouts. Not the laser printers with iron oxide toner which becomes a permanent part of the clay decoration (wish I would have kept my old HP!), but just a regular inkjet printer that leaves temporary guidelines on the slab. I print out my file from Adobe Illustrator (in reverse and with a 2 pt. border), lay ink-side down on a wet-stage clay slab, and burnish the paper lightly to transfer the image onto the clay. To cut out the tiles, I wait until the slab is leather hard, line up my ruler on the inked border lines and make the cuts. You’ll see me use this method on future demo slabs.
One last thing, while I’m separating my cut pieces into different sets for each technique I’ll be demonstrating with this particular slab, it would likely be much more efficient when creating a larger number of pieces to use one technique, underglaze, glaze, etc. at a time.
Now get back to that clay, you know you want to!!!
So now I’ve rolled out a slab, what’s next?
I’ll need the clay to vary from leather-hard on some pieces to bone dry on others in order to best apply the surface treatments I’ve chosen for the pieces I’m making out of this slab. There are other techniques that work better when the clay is still at wet-stage, such as adding sprigs and joining pieces for additive high relief, slip trailing/brushing, and adding impressions/texture to the slab, but I won’t be using any of those on these pieces (with the exception of stamp impression, which can be done at wet or leather-hard stage with a hard-surface stamp such as bisque, wood, or plaster).
-To test if a slab is leather-hard, I try gently moving the slab by pushing opposing corners, without forcing it. When it pulls away from the board and moves easily, it’s ready to cut out.
Here's a photo of the pieces where they are right now, ready for bisque firing. I'll point out real quickly which decorating techniques I'll be demonstrating in upcoming videos, and then I'll let you get on to the Cutting Out/Prep video:
Cutting out, cleanup and prep of clay tiles and pendants Video:
Supply List:
-Rolled slab of clay, dried to leather-hard stage
-Sponge/small bucket of clean water
-Pin Tool, Xacto knife, or fettling knife (for cutting clay)
-Ware board approx. 1 sq. ft. plywood, fiber board, masonite, wallboard or other hard porous work surface
-Small pastry roller (optional)
(1) Template method:
-Cereal carton or cardboard box (to make template out of)
-Scissors or Xacto knife (cutting out template)
(2) Shape Cutter method:
-Shape cutters (I mainly use these plastic ones and sometimes these Kemper rose cutters on thinner slabs
-Cornstarch
Pendant prep supplies:
-Ball-tipped tool (Kemper BSL) or Wooden skewer, even a large needle or small quill works (for drilling holes)
OR
-High Temperature Wire (other gauges available, I use 24 gauge but it is very light, like Xmas ornament wire)
-Wire cutters
-Small pliers
(other gauges available, I use 24 gauge but it is very light, like Xmas ornament wire)
Method 1: Using a Template
Step 1: Make a template by first measuring/drawing the size & shape you want your tile to be onto a flat carton or piece of cardboard (you’ll likely need a power saw for making a plywood cutout). For measuring squares/rectangles I use a framing square, a compass for circles, triangles for angles, etc.). Cut the shape out of the carton using scissors or an Xacto knife (the scissors are much easier to use on beverage/cereal cartons, the Xacto is easier on corrugated cardboard).
Step 2: Place the template on the slab and begin making the cuts along the edge of the template, always drawing the blade towards you when cutting while holding the template firmly in place. Keep the blade/pin tool straight up and down as you cut or at a very slight outward facing angle. Make all of the cuts and then remove the template.
Step 3: Soften each tile’s corners (they tend to be the first part of the tile to dry out and crumble if left at a sharp angle) by cutting a tiny piece off at a slight angle and then gently rounding and pushing them in with your fingers. When the tiles are firm enough to pick up (past the stage of bending easily), gently soften the edges of the tile with your pin tool, a wood tool, or your finger and then run and blot a clean, barely damp sponge over the edges and the rest of the tile.
-Step 4: See **’Drying Method’ below
Method (2): Using cutters to cut out shapes:
Step 1: Rub a little cornstarch between your fingers and then run your fingers over the sides of the cutter (this is only necessary on the cutters without the release plunger).
Step 2: Push the cutter straight down with even pressure into the clay. Hold the surrounding slab down as you pull the cutter out. The cut piece will likely be in the cutter instead of having remained on the slab. Apply firm pressure to an edge or two of the clay from the top of the cutter to push it out onto the work board. Once the piece has released from the cutter, gently pat down the piece to flat again if it has bent out of the cutter. Using a flower/pastry roller helps to flatten the tile again.
Step 3: See **Drying Method below
The following steps are for Pendant prep (drilling holes or placing high temp wire):
-I work on one pendant at a time, taking it from under the bag leaving the others covered. If I’m going to be stamping a raised image onto the front face, I press the image in before drilling the the stringing hole or inserting the high temperature wire.
a) High Temp Wire: High temperature wire can be purchased from a ceramic supplier and is useful when you want to eliminate a hole in your pendant. Using it instead of a hole also makes glazing prep and clean up a lot faster, is easier to fire, and provides a built in ring for attaching the finished pendant easily to a cord or jump ring.
Step 1: Prepare the wire loops before cutting out your pendants. I make a bunch at a time and store them for later use. Make a loop by bending a short (approx. 2”) length of the wire in half, and then wrapping one end of the wire around the other end. Keep the end that is being wrapped in a straight line with the hoop while the other end is twisted around it.
Step 2: Lightly squeeze both faces of the pendant on either side of the place you’ll be inserting the wire. Push the twisted end of the wire straight into the side of the pendant; your other fingers will be able to help guide the wire and keep it from splitting through the face. It’s better to keep the end towards the back face of the pendant so that if it burns through a bit in the firing it won’t affect the front face.
-Once the wire is in place, try not to move it around or hold the piece by the wire. After it’s bisque fired, you’ll be able to hold the piece (for glazing and such) by the wire without it coming loose. I’ve really tugged on them, trying to pry them loose after bisque firing, but they’re in there for the duration. You will however still be able to twist the loop after firing, so you don’t have to worry about facing the loop forward or sideways before firing. A thicker gauge of wire than I’m using (24 gauge) may not be as flexible after firing.
b) Drilling a Hole through the pendant instead of using high temp wire: Place an index finger on the side of the pendant, just above where you’ll be drilling the hole. This will help prevent the top side from cracking through if you make the hole too close to the top edge. With the pendant face-up and flat on the board, push a ball-tipped tool straight from the front to the back. Pick up the pendant and clean the clay from the exposed tool on the back before pulling it through to the front again. Level the area around the hole and pass the tool through the clay again, towards the front this time. These same steps are taken when using a wooden skewer instead of a tool. Dampen the end of the skewer with water before turning it in circles while at the same time pushing it through the clay.
**Drying Method for all Cut Pieces: After cleaning up the tiles/pendants, I place them back on the work board. They are now ready to decorate, or I’ll cover the whole board/tiles with a plastic bag if I’ll be away a few hours. If away from the pieces for more than a couple of hours, I’ll cover the board itself with a plastic bag, then lay the tiles on the plastic-covered board, and then cover the whole thing with yet another plastic bag. Spraying a fine water mist into the bag every once in a while helps slow down drying. The pieces can be kept almost indefinitely this way, until you’re ready to work on them. When they are then decorated, you’ll want to dry your pieces slowly and evenly by keeping them under plastic and exposing them once in a while to air, and then turning them over and covering them again, and repeating for a couple of days. Slower, even drying will help prevent warpage.
----------------------------------
Added Notes on Templates: Can be made from just about any material from paper to cereal cartons, corrugated cardboard, or a piece of plywood if you’re going to be cutting many multiples of the same size and shape and need the template to last a long time. In the video I’m making a 2” square template from a cereal carton and using it as a template to cut out a single tile. You may want to utilize a rectangular shaped template for cutting up a whole slab at one time.
To give you an idea how that works, here’s a Ceramic Arts Daily video with Angelica Pozo who shows how to use rectangular templates from masonite for cutting up larger groups of tiles:
Templates can be used for cutting out at any stage of clay dryness between wet to leather-hard. Unless I’m attaching pieces (sprigs) to wet clay, I usually wait until leather-hard for cut-out; it leaves cleaner, more workable edges. Wet clay is very easy to tear and smoosh so more care has to be taken when cutting it.
Added Notes on Using Shape Cutters: I usually use this method for smaller pieces like pendants, but I also use them quite often in cutting out tiles as well. The two sets of cutters I use are a) 3/4”H plastic cutters, which vary from 1.5” to 5.5” squares, circles, hexes, ovals, stars and hearts; and Kemper’s rose cutter set, which are 1/4”H circles that vary from 1/2” to 2” in diameter. This last set has a plunger release feature which ejects the piece of clay from the cutter, but they don’t work well on slabs over 1/8” thick; the plunger also leaves a circular impression on the pendant face. I usually use this set for circular pendants that I’ll be stamping, using the impression left by the cutter as a guideline for my stamp.
You can also use cookie or pastry cutters, available from gourmet and chef suppliers. Tile cutters for making larger, standard sized (4.25” and 6”) tiles are available from ceramic suppliers, these have spring loaded releases to keep the tile flat on the board at all times. They cost around $50.
It’s best to wait until the slab is at the firmer stages to use cutters as they tend to stick and bend the clay more when used in wet stage clay.
--------------------------------
Added Notes on Other Forming and Shape Cutting Methods Not Included in Video:
There are several other ways to make tile and pendant forms from clay that don’t always involve slabs such as small push molds, coils (for beads and jewelry), slip casting, and extrusion…the first two I’ve used and will eventually make videos for, but I haven’t tried the last two yet.
One last method that I use quite a bit but again didn’t cover in this video is the use of computer printouts. Not the laser printers with iron oxide toner which becomes a permanent part of the clay decoration (wish I would have kept my old HP!), but just a regular inkjet printer that leaves temporary guidelines on the slab. I print out my file from Adobe Illustrator (in reverse and with a 2 pt. border), lay ink-side down on a wet-stage clay slab, and burnish the paper lightly to transfer the image onto the clay. To cut out the tiles, I wait until the slab is leather hard, line up my ruler on the inked border lines and make the cuts. You’ll see me use this method on future demo slabs.
One last thing, while I’m separating my cut pieces into different sets for each technique I’ll be demonstrating with this particular slab, it would likely be much more efficient when creating a larger number of pieces to use one technique, underglaze, glaze, etc. at a time.
Now get back to that clay, you know you want to!!!
Thursday, April 4, 2013
Rolling a Clay Slab
Rolling out a slab of clay.
Supplies:
Any type of clay body (earthenware, stoneware, or porcelain),
A ruler
--2 strips of wood: 12” Long x 2 “ Wide x 1/4” High (from a home improvement store)
--2 sheets of canvas, cut to around 18” x 18” (from a fabric store) --
Roll the slab directly on drying boards for mid or high fire clay (generally stonewares and porcelains in the cone 5-11 range), and flip the slabs on the boards instead of the canvas. See my last post about using mid and high fire range clays, I'll only covering low-fired clay bodies until I've tested the others for myself a few times.
--rolling pin (unfinished wood is best)
--cutoff wire, you can use a guitar string or heavy nylon
--pin tool, fettling knife, or other blade, even a pizza cutter will work
--A piece of approx. 12” square plywood, fiberboard, wallboards, or any other porous surface to dry your clay on.
My video for slab rolling (click the Youtube icon to view larger in new window):
I make tiles that are 1/4” thick and the pendants are usually 1/8”, though I’ll sometimes make them 1/4” to add a little weight to them. Even at 1/4” thick, the finished, glazed white clay 1 1/4” oval pendants weighs just 10 grams. A stoneware/porcelain or a mix of the two would weigh considerably more, due to their greater mass.
Step 1: Use your ruler to make a mark into the block of clay on all four sides at 1/2” down from the top of the block. These are your guides in lining up the cutoff wire. A 1/2” cut piece off the block will roughly double its area once it is rolled out to 1/4” thickness.
Step 2: Line up the middle of your cutoff wire with the bottom of the ruler mark on the side of the clay block that is facing away from you. Then loosely wrap the wire around both sides of the block of clay, keeping it at the bottom of the ruler marks, without yet cutting into the clay block. Continue bringing both ends of the wire around to the front. When both sides of the wire handles meet at the front, bring the handles together and pull the wire straight back through the clay. Run your fingers
along the wire to remove the clay before it dries there.
Step 3: Remove the cut piece from the block of clay and drop it straight down on the canvas. Flip it over to the other side into your hand by pulling up the canvas and then drop it straight down again. Place the slab in the center of the canvas. Re-tie the bag of your clay block so that it won’t dry. Use your fingers to push and slap the cut slab into the most even thickness possible, if it’s not already pretty even.
Step 4: Place the pieces of 1/4” H wood on either side of the clay.
Step 5: Start rolling the clay, first straight back and forth, then diagonally from each corner back and forth, and then turn the canvas 90 degrees and roll back and forth again. (Think of the Union Jack flag and roll in that configuration; it’s also very similar to rolling out a pie crust). Pick up your rolling pin between each swipe, as keeping it continuously on the surface of the clay may cause the clay to stick to and curl around the roller.
Step 6: Remove the wood strips and place the other sheet of canvas over the top of the slab. Grab the edges of both sheets of canvas and using your hand as leverage on top, flip over the slab and both sheets of canvas.
Step 7: remove the top sheet of canvas, place the pieces of wood on the sides of the slab again and begin the rolling pattern over again.
Step 8: keep repeating the rolling and flipping until the rolling pin rolling only on the strips of wood and is no longer stretching the clay. If the clay gets wider than the rolling pin, use a pin tool or cutting tool to trim back the edges of the slab to a smaller size.
(You can save these trimmings by putting them in a plastic bag for future use; these can be used to roll into coils for making beads, or rolled into another mini-slab for stamps, texture mats, pendants, whatever. Just mash all the still-wet clay into a ball shape and either separate and roll into coils right away (the clay has to be pretty fresh off the block to make coils without cracks, unless you add some more water to it), or roll into a ball to throw down hard into a flat shape, and then roll out again.)
You can stop rolling when the slab reaches 1/4” thickness, or replace the wood strips (paint stirrers are just the right height) with 1/8” strips and keep rolling until it reaches that thickness. When it's at the thickness you want, trim off the edges again, as they are often thinner than the rest of the slab.
When you're done rolling, transfer the slab to a piece of plywood or fiber board by placing your hand over the top of the slab and using the canvas to flip it, pulling your hand away as you ease the slab onto the plywood. If you’ve rolled the slab out on a piece of plywood, you can simply place another piece of plywood on top of the clay and flip the whole thing over like you have been doing, or keep it at the side it’s on. Remove the sheet of canvas. Using a metal rib or a damp sponge, scrape/wipe the top of the clay to remove the canvas marks, unless you’re going to use the canvas texture in your design.
Now what are you going to do with it? If you’re going to use additive clay techniques such as sprig molded pieces, slip joined pieces or relief sculpture, and for impressing with many stamps or textures, the wet ware stage is the best time to join attachments, etc. I've stamped into clay that is pretty firm and still come away with a pretty solid impression, though.
If you’re decorating the surface at leather hard stage, the slab will take a couple of hours covered in canvas, paper, board for it to get firm enough to start working with, depending on the humidity and temperature conditions in your room. Wait until the slab moves freely on the board when you gently push adjacent corners to see if it can move free of the board. Then you can slide it around a little to work with the shape you'll cut. It’s usually dry enough to cut at that stage and still get a nice clean line without much fuss. So grab a nice cup of herbal tea and draw out some designs first if you like of what you'll put on the clay, or maybe consider which tools you’ll be using for decorating if you’re going to freehand your design. Look through some of the books I've listed, many of which are available at the library. The surface decorations that I'll be demonstrating can be found in detail within their pages, and you'll refer to them again and again. Good pottery books are always worth the investment because you'll use them a lot, so if you find one that you find helpful, keep a copy around. Before long you'll have plenty of reference materials.
Next it’s time to start cutting out your pendant or tile shapes and making holes in the pendants and cleaning them up to have them ready for decorating and bisque firing. Be back next week, but for now it's back to the clay!
Supplies:
Any type of clay body (earthenware, stoneware, or porcelain),
A ruler
--2 strips of wood: 12” Long x 2 “ Wide x 1/4” High (from a home improvement store)
--2 sheets of canvas, cut to around 18” x 18” (from a fabric store) --
Roll the slab directly on drying boards for mid or high fire clay (generally stonewares and porcelains in the cone 5-11 range), and flip the slabs on the boards instead of the canvas. See my last post about using mid and high fire range clays, I'll only covering low-fired clay bodies until I've tested the others for myself a few times.
--rolling pin (unfinished wood is best)
--cutoff wire, you can use a guitar string or heavy nylon
--pin tool, fettling knife, or other blade, even a pizza cutter will work
--A piece of approx. 12” square plywood, fiberboard, wallboards, or any other porous surface to dry your clay on.
My video for slab rolling (click the Youtube icon to view larger in new window):
I make tiles that are 1/4” thick and the pendants are usually 1/8”, though I’ll sometimes make them 1/4” to add a little weight to them. Even at 1/4” thick, the finished, glazed white clay 1 1/4” oval pendants weighs just 10 grams. A stoneware/porcelain or a mix of the two would weigh considerably more, due to their greater mass.
Step 1: Use your ruler to make a mark into the block of clay on all four sides at 1/2” down from the top of the block. These are your guides in lining up the cutoff wire. A 1/2” cut piece off the block will roughly double its area once it is rolled out to 1/4” thickness.
Step 2: Line up the middle of your cutoff wire with the bottom of the ruler mark on the side of the clay block that is facing away from you. Then loosely wrap the wire around both sides of the block of clay, keeping it at the bottom of the ruler marks, without yet cutting into the clay block. Continue bringing both ends of the wire around to the front. When both sides of the wire handles meet at the front, bring the handles together and pull the wire straight back through the clay. Run your fingers
along the wire to remove the clay before it dries there.
Step 3: Remove the cut piece from the block of clay and drop it straight down on the canvas. Flip it over to the other side into your hand by pulling up the canvas and then drop it straight down again. Place the slab in the center of the canvas. Re-tie the bag of your clay block so that it won’t dry. Use your fingers to push and slap the cut slab into the most even thickness possible, if it’s not already pretty even.
Step 4: Place the pieces of 1/4” H wood on either side of the clay.
Step 5: Start rolling the clay, first straight back and forth, then diagonally from each corner back and forth, and then turn the canvas 90 degrees and roll back and forth again. (Think of the Union Jack flag and roll in that configuration; it’s also very similar to rolling out a pie crust). Pick up your rolling pin between each swipe, as keeping it continuously on the surface of the clay may cause the clay to stick to and curl around the roller.
Step 6: Remove the wood strips and place the other sheet of canvas over the top of the slab. Grab the edges of both sheets of canvas and using your hand as leverage on top, flip over the slab and both sheets of canvas.
Step 7: remove the top sheet of canvas, place the pieces of wood on the sides of the slab again and begin the rolling pattern over again.
Step 8: keep repeating the rolling and flipping until the rolling pin rolling only on the strips of wood and is no longer stretching the clay. If the clay gets wider than the rolling pin, use a pin tool or cutting tool to trim back the edges of the slab to a smaller size.
(You can save these trimmings by putting them in a plastic bag for future use; these can be used to roll into coils for making beads, or rolled into another mini-slab for stamps, texture mats, pendants, whatever. Just mash all the still-wet clay into a ball shape and either separate and roll into coils right away (the clay has to be pretty fresh off the block to make coils without cracks, unless you add some more water to it), or roll into a ball to throw down hard into a flat shape, and then roll out again.)
You can stop rolling when the slab reaches 1/4” thickness, or replace the wood strips (paint stirrers are just the right height) with 1/8” strips and keep rolling until it reaches that thickness. When it's at the thickness you want, trim off the edges again, as they are often thinner than the rest of the slab.
When you're done rolling, transfer the slab to a piece of plywood or fiber board by placing your hand over the top of the slab and using the canvas to flip it, pulling your hand away as you ease the slab onto the plywood. If you’ve rolled the slab out on a piece of plywood, you can simply place another piece of plywood on top of the clay and flip the whole thing over like you have been doing, or keep it at the side it’s on. Remove the sheet of canvas. Using a metal rib or a damp sponge, scrape/wipe the top of the clay to remove the canvas marks, unless you’re going to use the canvas texture in your design.
Now what are you going to do with it? If you’re going to use additive clay techniques such as sprig molded pieces, slip joined pieces or relief sculpture, and for impressing with many stamps or textures, the wet ware stage is the best time to join attachments, etc. I've stamped into clay that is pretty firm and still come away with a pretty solid impression, though.
If you’re decorating the surface at leather hard stage, the slab will take a couple of hours covered in canvas, paper, board for it to get firm enough to start working with, depending on the humidity and temperature conditions in your room. Wait until the slab moves freely on the board when you gently push adjacent corners to see if it can move free of the board. Then you can slide it around a little to work with the shape you'll cut. It’s usually dry enough to cut at that stage and still get a nice clean line without much fuss. So grab a nice cup of herbal tea and draw out some designs first if you like of what you'll put on the clay, or maybe consider which tools you’ll be using for decorating if you’re going to freehand your design. Look through some of the books I've listed, many of which are available at the library. The surface decorations that I'll be demonstrating can be found in detail within their pages, and you'll refer to them again and again. Good pottery books are always worth the investment because you'll use them a lot, so if you find one that you find helpful, keep a copy around. Before long you'll have plenty of reference materials.
Next it’s time to start cutting out your pendant or tile shapes and making holes in the pendants and cleaning them up to have them ready for decorating and bisque firing. Be back next week, but for now it's back to the clay!
Wednesday, April 3, 2013
Clay Bodies and Glazes that I'm Using and why
I'm currently using two types of clay body, low-fire: white clay and terra cotta
earthenware clay. I like the variety of commercially available glazes in
this firing range, and the 'forgiving' nature of the clay itself. By
forgiving, I mean that when I bend a piece of the clay and then flatten
it out again, it won't warp to the bent shape later while drying or
during firing like a porcelain body would be more prone to do. I'd like
to go to mid range temperature stoneware by year's end, but I'm enjoying
the lower fuel costs in the meantime while I learn how to use the
different tools and techniques. I would also love to eventually work
with porcelain, nothing compares to it's beauty, but I don't feel I'm
ready for the high temp firings just yet. I've read that porcelain is
for the more experienced hand. I'm not making functional ware (eating
utensils, teapots, or flower vases for example) or tiles/jewelry that
will be continually wet, so I'm not highly concerned with the piece
being vitreous; I glaze the entire surface so as to maximize resistance
to moisture. I use Laguna's #10-T white clay, and their #20 red earthenware (these are Northeast clays). The note in the supply list of the next post, about rolling out mid to high fire glazes shows why I haven’t yet started firing clay in the upper cone ranges, plus a few other reasons like I’m just starting out. When making a flat ceramic piece for tile or flat jewelry, keeping the raw clay slab flat at all times is more important in those higher cone range clay bodies, though I've heard that stoneware or a mix of stoneware/porcelain properties is easier to work with than a purer porcelain body. Stoneware and porcelain bodies are denser, and so have more ‘memory’. The increased number of platelets in the clay remember every shape you bend them into, and will try again at all stages of drying and firing to re-bend to those shapes.
That density of platelets, there because of the chosen formula of materials used in mixing the clay body, is also what makes stoneware and porcelain ware able to sustain higher temperature firings to become vitreous/glasslike, very strong and impervious to liquid. I can fire a low fire clay to it’s near-vitreous state, and the fired piece will have a ‘ring’, but the finished piece will be quite brittle and fragile in comparison to stoneware or porcelain clay bodies at higher cone temperatures. Also, bringing a clay to its near melting point in order to achieve a vitreous clay is not the main quality I'm looking for right now. Like I said I’m not making outdoor sculpture (water will get in and at freezing temperatures crack the piece), tile that will be in continuous contact with water like bath surround tiles, or with food and hot liquids like eating/drinking utensils, or functional flower vases; for now I’m making tiles to hang on an inside wall as is or in a group, or to use as coasters. The ones I don’t like can be broken for mosaics.
I glaze the entire piece except the hole on jewelry pieces, and over the top and a bit over the edge for tiles. That helps to create more of a barrier between moisture and the fired clay, but still shouldn’t be exposed to continuous water for a long time or water seepage is more likely to grow within the clay structure and out through the glaze over time. Those cracks in the glaze allow a healthy environment for bacteria to live in the fired clay, so cracked glazes are ok on non-functional higher fire clay bodies that were fired to their higher cone rating, but not so great on low fire clay bodies that haven’t been fired to their highest cone rating. At the lower end of their cone ratings, low fire clay bodies are still considered ‘open’, porous/punky, even after bisque and glaze firings when not brought to their upper cone rating. You can feel it in the weight, they feel almost as light as air (because they’re holding a lot of air!) Still, the pieces that I make will be around for a really long time…pottery shards of unglazed earthenware are thousands, sometimes tens of thousands of years old in the right conditions. That’s a lot longer than I expect to be around to see it deteriorate, and that's if I’ve glazed them well. So glazed low fire white clay and red earthenware is right for my application.
I’ll try and mention what I can now and then about the upper firing ranges (cones 5-8 for mid and cones 8-11 for high fire, approximately), but until I’ve experimented myself with them I probably won’t have much to add. That’s one of the main reasons I started this blog anyways, to organize my links to studio/production potters/artists and other pros within the industry who have many more answers than I do, the ones that I look to when I need answers, and there are a billion questions. I’m a lifelong learner so I don’t mind spending the time reading, practicing and experimenting; I’m in it for the long haul because of the clay itself and the way it makes me feel when I’m being creative with it. It’s something to look forward to, every day, and helping me to live in the present moment and appreciate life here on our beautiful planet and the gifts that it has bestowed upon all of us.
I use commercially prepared glazes and underglazes because at the scale I'm working at it doesn't make much sense for me to make my own yet. A two ounce jar of underglaze can cover a lot of pendants and tile! Plus there are tons of colors and textures available from several companies. Here are their color charts: Duncan, Amaco, Spectrum, Mayco and Laguna have underglazes and both low fire and mid fire range glazes, and Coyote has underglazes and mid fire glazes (cone 6). I'll be adding a list of great ceramic suppliers in the coming posts.
I'm reading all that I can on glaze chemistry at the moment, so who knows? It's yet another of my goals to someday mix and test my own batches. Be here for that, too, those first tests ought to be ...'interesting' shall we say. I'm using about a half dozen or so Duncan Envision transparent glazes and a handful of Amaco underglazes, both the LUG and Velvets series. I use the clear transparent LG-10 Amaco glaze over the underglazes. Both Duncan and Amaco have shown to be excellent product lines that 'fit' my clay body really well. My kiln is an Olympic Doll Kiln, just the right size for jewelry components and small (less than 4") tile. I dream of a gas kiln someday, don't we all, but I figure at the rate I make things now it would probably take me the better part of the year to fill more than a couple cubic feet of kiln space (mine is less than .5 cubic foot).
Here's a pic from my 2nd glaze firing:
Bad lighting... maybe I should leave pictures to my photographer daughter. I'll be going over all of the techniques you
see here in the coming months: stamp making, sgraffito, patinas...and I
have a bunch more that I'll be trying out for the first time including
slip trailing, paper resist, wax resist & cuerda seca, terra
sigillata, I have a long bucket list of things I *neeeeed* to try with
clay. I'll start from the beginning with slab rolling and work from
there. So take a trip to your ceramic supply store and pick up some clay
for goodness sake, you know this is what you want to do with your life!
That density of platelets, there because of the chosen formula of materials used in mixing the clay body, is also what makes stoneware and porcelain ware able to sustain higher temperature firings to become vitreous/glasslike, very strong and impervious to liquid. I can fire a low fire clay to it’s near-vitreous state, and the fired piece will have a ‘ring’, but the finished piece will be quite brittle and fragile in comparison to stoneware or porcelain clay bodies at higher cone temperatures. Also, bringing a clay to its near melting point in order to achieve a vitreous clay is not the main quality I'm looking for right now. Like I said I’m not making outdoor sculpture (water will get in and at freezing temperatures crack the piece), tile that will be in continuous contact with water like bath surround tiles, or with food and hot liquids like eating/drinking utensils, or functional flower vases; for now I’m making tiles to hang on an inside wall as is or in a group, or to use as coasters. The ones I don’t like can be broken for mosaics.
I glaze the entire piece except the hole on jewelry pieces, and over the top and a bit over the edge for tiles. That helps to create more of a barrier between moisture and the fired clay, but still shouldn’t be exposed to continuous water for a long time or water seepage is more likely to grow within the clay structure and out through the glaze over time. Those cracks in the glaze allow a healthy environment for bacteria to live in the fired clay, so cracked glazes are ok on non-functional higher fire clay bodies that were fired to their higher cone rating, but not so great on low fire clay bodies that haven’t been fired to their highest cone rating. At the lower end of their cone ratings, low fire clay bodies are still considered ‘open’, porous/punky, even after bisque and glaze firings when not brought to their upper cone rating. You can feel it in the weight, they feel almost as light as air (because they’re holding a lot of air!) Still, the pieces that I make will be around for a really long time…pottery shards of unglazed earthenware are thousands, sometimes tens of thousands of years old in the right conditions. That’s a lot longer than I expect to be around to see it deteriorate, and that's if I’ve glazed them well. So glazed low fire white clay and red earthenware is right for my application.
I’ll try and mention what I can now and then about the upper firing ranges (cones 5-8 for mid and cones 8-11 for high fire, approximately), but until I’ve experimented myself with them I probably won’t have much to add. That’s one of the main reasons I started this blog anyways, to organize my links to studio/production potters/artists and other pros within the industry who have many more answers than I do, the ones that I look to when I need answers, and there are a billion questions. I’m a lifelong learner so I don’t mind spending the time reading, practicing and experimenting; I’m in it for the long haul because of the clay itself and the way it makes me feel when I’m being creative with it. It’s something to look forward to, every day, and helping me to live in the present moment and appreciate life here on our beautiful planet and the gifts that it has bestowed upon all of us.
I use commercially prepared glazes and underglazes because at the scale I'm working at it doesn't make much sense for me to make my own yet. A two ounce jar of underglaze can cover a lot of pendants and tile! Plus there are tons of colors and textures available from several companies. Here are their color charts: Duncan, Amaco, Spectrum, Mayco and Laguna have underglazes and both low fire and mid fire range glazes, and Coyote has underglazes and mid fire glazes (cone 6). I'll be adding a list of great ceramic suppliers in the coming posts.
I'm reading all that I can on glaze chemistry at the moment, so who knows? It's yet another of my goals to someday mix and test my own batches. Be here for that, too, those first tests ought to be ...'interesting' shall we say. I'm using about a half dozen or so Duncan Envision transparent glazes and a handful of Amaco underglazes, both the LUG and Velvets series. I use the clear transparent LG-10 Amaco glaze over the underglazes. Both Duncan and Amaco have shown to be excellent product lines that 'fit' my clay body really well. My kiln is an Olympic Doll Kiln, just the right size for jewelry components and small (less than 4") tile. I dream of a gas kiln someday, don't we all, but I figure at the rate I make things now it would probably take me the better part of the year to fill more than a couple cubic feet of kiln space (mine is less than .5 cubic foot).
Here's a pic from my 2nd glaze firing:
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