Creating Subtle Layers with Sgraffito, Slip, and Multi-Toned Glazes

I just love the sugary matt surfaces, color schemes, and subtle layers in Kristin Pavelka’s work. Kristin uses gorgeous red earthenware to her advantage by creating linear sgraffito marks through white slip. Then she creates subtle layers of glazes–often using two tones of the same color–in a paint by number fashion. The result is work that looks as yummy as a frosted sugar cookie.

In this post, Kristin explains these decorating techniques. She also shares glaze and slip recipes! – Jennifer Poellot Harnetty, editor.


Decorating with Slip and Sgraffito

figure 7. Pour white slip onto the middle of the plate, turning the piece clockwise until the entire face is covered.

I slip my pots when they look dry but have a small bit of moisture in them. This allows for a relatively even coating of slip, yet it dries a bit slower giving me time to complete my sgrafitto before the slip starts to chip when scratched. Because the slip dries quickly, I have to work fast to complete my design, so I plan the patterns ahead of time in a sketchbook or by drawing with a soft pencil on the unslipped plate itself.

Once I’ve decided on a pattern, I can begin slipping. Holding the plate vertically, I pour the white slip onto the middle of the plate using a large ladle, turning the piece clockwise until the entire face is covered (figure 7). Keep the plate vertical until the slip drips have firmed, then rest the plate on the tabletop and allow the slip to dry for a few minutes until you can touch it without a fingerprint remaining, but while it still feels cold and damp.

figure 8. Scratch through the slip so that the tool just barely digs into the underlying clay.

Lightly draw a grid on the piece using a soft pencil, like a 2B. Breaking up the space symmetrically on a circular form is a quick and easy way to understand the space. I sometimes draw my pattern on the piece to double check the placement of key elements, but usually I draw directly with my sgraffito tool using just the grid as an aid for placing the design.

My sgrafitto tool had a previous life as a dentistry tool and is thicker and duller than a standard needle tool. A long nail with a dull point is a good substitute. The line created is thicker than an X-Acto blade or needle tool and can give a similar line quality as a standard-sized pencil lead. Medium pressure is exerted with the tool tip so that it scratches through the white slip and just barely digs into the red underlying clay (figure 8). I brush a stiff yet soft-bristled brush across the surface of the plate once the design is carved to clean up the edges of the incised lines as well to rid the surface of the slip crumbs (figure 9).

figure 9. Brush the surface once the design is complete to clean up the edges of the incised lines.

Finally, a Scotch Brite pad is lightly rubbed along the rim to help expose the red earthenware beneath. This helps create more depth in the surface once it has gone through the glaze firing.

Note: For all three of the above steps that create crumbles or fine powder, wear a mask and work over a bucket of water to minimize the amount of dust entering the air and to make clean-up easier.

 


Create surfaces that will turn heads!

Erin Furimsky shows you how in her Layered Surfaces DVD!


Glazing by Numbers

figure 10. Load up a small brush with the darker-toned glaze and fill in the pod shapes on the bisque-fired plate.

I bisque fire to cone 01, then, to prepare the piece for glazing, give it a good shower under running water to clean any leftover sgrafitto dust from the surface. Leave the piece to dry overnight. The first glaze application is much like a paint-by-number painting. Often using two tones of the same color, I’ll load up a small brush with the darker tone and fill in the “pod” shapes. Little pressure is used when painting as the glaze should flow from the brush onto the bisque, eliminating brush strokes (figure 10). I fill the sgrafitto lines with this first glaze, which helps eliminate pinholes in the glaze-fired impression. This first layer of glaze is left to dry several hours to overnight.

The second, lighter tone of glaze is then poured on the plate in a similar fashion to the white slip—rotating a vertically-held plate clockwise while pouring the glaze in the middle of the piece (figure 11). This second coat is left to dry.

figure 11. Once the first glaze is dry, apply a coat of a lighter-toned satin glaze using the same technique as for pouring the slip.

figure 11. Once the first glaze is dry, apply a coat of a lighter-toned satin glaze using the same technique as for pouring the slip.

The final glazes are now ready to be applied to the dots using a small soft brush or a fingertip. I can usually see a light indentation of the sgrafitto dot through the poured glaze to use as a guide for dot placement. If I am unable to determine where to place my dot within the design, I sometimes guess and other times fire the piece and then apply the dots to the fired glaze and refire. The final dots are made up of a lighter-toned large dot with a smaller dark toned dot on top (figure 12).

The dry, glazed piece is fired to cone 04, held at that temperature for 15 minutes and then fired down to cone 010 before being turned off. This schedule helps to produce a nice satiny finish to the glaze surface.

Kristin Pavelka is a full-time studio potter living in Maplewood, Minnesota. To see more of her work visit www.pavelkapottery.com.

figure 12. Apply the accent glazes, starting with the lighter glaze, and finishing with small dots of darker glaze.


 

**First published in September 2011
Comments
  • Kristin makes such great pots. Nice to see her featured.

  • I enjoyed your technique… I’m going to experiment. Thank you.

  • Audrey W.

    Something new to try. Thank you for sharing. Always interested in surfaces. Audrey Worman

  • Can someone tell me what is a nice white and red cone 04/05 clay to use? I am using Bmix, a cone 5 clay that I love and want a nice smooth clay with some tooth to it.

  • Hi Kristen,

    Is there an error in the recipe for Kat Red? The base components add up to 90.4% rather than 100%.

    Liz

  • Kristin P.

    Liz,

    The recipe is correct, but yes, the components do not add up to 100% The corrected numbers should read as follows to add up to 100%.

    Wollastonite: 15
    Frit 3195: 47
    EPK: 26
    Flint: 12

  • Kathy M.

    Could you please specifically explain, “then fired down to cone 010 before being turned off.”? Does this mean after the 15 minute hold, kiln is set to cone 010 and then once it reaches cone 010 I shut the kiln off? Thank you!

  • Sherry R.

    I am just starting to investigate earthenware clay as I normally use stoneware. I am a bit confused and am having trouble finding out about the firing. I was told that you sort of do things backwards, fire the bisqueware to 04 which brings it to vitrification and then glaze to 03. You indicate you fire to 01, then glaze. could you help me? Thanks

  • Julie J.

    I was excited to find a pourable earthenware glaze. But I mixed up the Satin Base with the mason stains and it is thin as water. I added a ton of epsom salt solution and poured off as much water as possible from settling. Is there something missing from the recipe? It doesn’t have much clay, are the numbers perhaps off? Not sure what to do with what I got, it is not even brushable. I used a lot of mason stains that I’m not happy to throw out.

  • Kristin,
    On your “frosted maiolica glaze, how much difference would it make if one were to use all EPK instead of half each Georgia Kaolin and EPK?

    Love your work by the way!

    judy

Enter Your Log In Credentials
This setting should only be used on your home or work computer.

Larger version of the image

Send this to a friend