HANDBUILDING - FALL, SEPTEMBER-OCTOBER 18, 2023

October 18, 2023
All of your works have been bisque fired. We were introduced to Surface Decoration last week with Underglazed. We used two strategies with this: newspaper resist and applicatio of tissue prints. The next stage will be to apply a clear glaze. For this class, we use Duncan Pure Brilliance which we fire to cone 05 (low fire).

We learned how to make underglazes by using a slip recipe with added colorants.

Strategies for Decorating the Surface of your Green ware using slips, underglazes and stamps

Slips and Stains

Hand built forms in clay include a mix of surface decoration which might include commercial underglazes, slips, stains and glazes. When considering colour and surface decoration, the word “slip” refers to a recipe based medium for a colorants. People working with clay commonly refer to slip and understand the word as a liquefied suspension of clay particles in water which occurs whenever one works with clay. There is also “slip-casting” which is also a recipe-based concept and used with molds.

Often handbuilt forms in clay include a mix of surface decoration which might include commercial underglazes, slips, stains and glazes (often just a clear glossy or matte). When considering colour and surface decoration, the word “slip” refers to a recipe based medium for a colorants. People working with clay commonly refer to slip and understand the word as a liquefied suspension of clay particles in water which occurs whenever one works with clay. There is also “slip-casting” which is also a recipe-based concept and used with molds.

Slips are applied to wet or soft leather-hard greenware. Slip used on bisque usually follows an engobe recipe. They can be washed away to create a weathered look.

 

Slips are applied to wet or soft leather-hard greenware. Slip used on bisque usually follows an engobe recipe. They can be washed away to create a weathered look.

 

Susan Feagin  (Cone 04-9) Custer Feldspar  27 EP Kaolin 34 OM4 Ball Clay 20 Sikica  19 -------- Zircopax  5

Sunshine Cobb Base Slip Cone 04-9 Kaolin  34 Ball Clay  20 Potash Feldspar  27 Flint-silica  19 Zircopax  8 Soda ash  0.25 Sodium Silicate  0.25 ____________________

Robin Hopper: WHITE BASE Cone 04-12 in Ceramic Spectrum): Ball clay 75 Kaolin 10 Silica 10 Feldspar 5

Colorants are added to the slips. There are two categories 1) Minerals 2) Mason Stains.
 I. Common minerals: Rutile (tan); Cobalt carbonate (blue – 1-3%); Iron Oxide (red-up to 15%); Copper Carbonate (green – up to 10%); chrome (darker green 1-3%).
2. Mason stains: infinite

Replace Underglazes with Engobes on Bisque Ware
Engobe recipe R Hopper –

Raw Material

Cone 04-3

Cone 4-6

Cone 6-10

Kaolin	20	15	15
Calcined Kaolin	10	20	35
Talc	25	10	5
Calcium Borate (or Frit 3110)	15	10	0
Nepheline Syenite	0	10	15
Silica	15	20	15
Borax	5	5	5
Zircopax	10	10	10
Total

 

Class Pictures are coming