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!
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