Old Man River Potters Guild - Surface Decoration Workshop

ORPG: Surface Decoration  - Low FireClear Glaze tests Cone 05/04

Deb’s Clear Base   Cone 04 Ferro Frit 3195   45 % Ferro Frit 3134   30 EPK Kaolin       25 100 % Butter Yellow: Add: Mason Stain 6464 Zirconium Yellow.. 2 % This glaze is transparent and shiny. Apply thin in order to ensure the fired glaze will be a transparent clear. It is very responsive to colorants. Use a thicker application with colorants to achieve a rich translucent glaze.

Hirsh Satin Matt Base (Cone 04–02) Gerstley Borate   32 % Lithium Carbonate  9 Whiting     17 Nepheline Syenite    4 EPK Kaolin   4 Silica (Flint)   35 100 % Add: Bentonite  2 %

What is SLIP?
*Slip (noun) is a liquefied suspension of clay particles in water and used in the production of ceramic ware.

* Most slips are made for application in the early leather hard stage

* A close relative of slip is slurry, which is generally thinner. Slip is usually the consistency of heavy cream.
*Deflocculants, such as sodium silicate or Darvan, can be added to the slip to disperse the raw material particles.

* A special slip called “casting slip” is used with mold-made shapes (these have a specific recipe).

*Slip is often used in decoration. It may be left the natural color of the clay body from which it is made, or it may be colored with mason stains or oxides. If colour is important, then a white slip is used.

*It is applied to wet or soft leather-hard greenware. (Slip used on bisque usually follows an engobe recipe).

Kathy Triplett: “Slips made from slurry will shrink much more than those made from casting slip, they won’t adhere as well unless special ingredients are added to minimize shrinkage…Add 3%-5% ceramic stains to any casting slip recipe”. In Handbuilt Ceramics by Kathy Triplett ( p. 141)

Uses of Slip

A slip may be made for various purposes in the production and decoration of ceramics. Slip can be used:

1.    To join of sections of unfired ware or greenware, such as handles and spouts (this may simply be a wetter version of the clay you are using or one with the addition of darvan or sodium silicate).

2.    Decoratively by adding mason stains – what you see is what you get (usually no more than10-15%). Traditional slipware uses oxides.

3.    To pour into a mold to create a form and called slip casting.

4.    To adhere figures or other motifs to unfired ware, called sprigging.

5.    To repair cracks in your greenware (with the addition of toilet paper)

6.    A specialized slip (engobe) is used to further decorate a bisque piece.

Application of underglaze slip
Underglazes can be applied by brushing, pouring, dipping, spraying, sponging—pretty much anything goes. Each application method has different requirements. If an underglaze is too thick for spraying or using as a wash, just add water to thin it down. If it’s too thin for silk screening or monoprinting, leave the container exposed to air to evaporate some of the liquid.

RECIPES

Low fire - white slip (cone 05, 06)

Carol Gouthro – low fire white slip (cone 05, 06) EPK 12.5 Calcined Kaolin  12.5 Ball Clay 25 Frit 3124  20 Talc 5 Silica 20 Zircopax  5

Robin Hopper: WHITE BASE SLIP   (will fit most clays & easily colored, cone 04-12 in Ceramic Spectrum): Ball clay 75 Kaolin 10 Silica 10 Feldspar 5 (at cone 2 or lower it may cause the glaze to craze)