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!
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