Test Tiles - For Glazing and Oxides

Transcription

1 Test Tiles - For Glazing and Oxides Why make Test Tiles? Making test tiles is a crucial way of learning how a glaze or oxide appears once it has gone through the firing process. There are many glazes/oxides out there to use and sometimes it s hard to get the exact finish you want by looking at the picture on the bottle! Glazes and oxides have different results due to the firing temperature in the kiln, the type of clay used and application method. Due to all these variations, it s good to use test tiles to experiment with! Testing glazes and oxides will help save you from disappointment. The last thing you want to do is ruin a piece that you ve been working on for weeks by putting on a horrible glaze that wasn t what you had in mind! Images sourced from online websites: creative-strategies/page/6/

2 Test Tiles - Gingerbread Men Introduction There are all kinds of test tiles shapes that you can make! I have opted for the gingerbread man - because I have a set of gingerbread cookie cutters sitting in my kitchen drawers! You can easily just make square tiles and cut these using a potters knife and ruler. They don t have to be perfect! It s also good to have some texture on the surface - this will give you an indication of how the glaze/oxide looks on an uneven surface.

3 Test Tiles Reference Sheet c (Low temp fire Glaze) Hole (optional) Test Tile Reference Letter Firing Temperature Clay Type My initials! (optional) Ref. Letter Glaze/Oxide Name Notes A B C D E F G H I

4 Test Tiles Reference Sheet c (Mid temp fire Glaze) Hole (optional) Test Tile Reference Letter Firing Temperature Clay Type My initials! (optional) Ref. Letter Glaze/Oxide Name Notes A B C D E F G H I

5 Test Tiles Reference Sheet c (High temp fire Glaze) Hole (optional) Test Tile Reference Letter Firing Temperature Clay Type My initials! (optional) Ref. Letter Glaze/Oxide Name Notes A B C D E F G H I

6 Pyrometric Cones (Orton Standard) Temperature Equivalent Chart Cone No. Centigrade / Earthenware This is the most common type of clay. Terra-cotta is one type of earthenware that is relatively coarse and red in color. Other earthenware bodies may be finer and have various colors, ranging from white to gray, buff and red. Earthenware clays are usually fired between 970c c. At this temperature the clay body is still porous and needs to be glazed, e.g. if it is to be used as dinnerware. Mid-Fire Mid-fire clays are a type of hybrid earthenware/stoneware clay that matures in between the two temperature ranges. This means that it is possible to get the qualities of the higher fired stoneware, while saving money and fuel in the firing. Mid-fire clays typically mature around 1150c c. Stoneware Stoneware clays are fired up to 1300c, where they become quite hard and vitreous. Colors range from off white to grey and dark brown. There are also various degrees of roughness or fineness, depending on the formulation. This the hardest, most durable type of clay. Porcelain Porcelain is a totally manufactured clay. While it is not synthetic as such, various natural ingredients are refined and mixed up according to formulas. A good porcelain must be very white, vitreous, translucent while at the same time being plastic enough to work with. Porcelain is fired from 1280c to 1400c. 1000c (Standard Bisque) c (Low Fire Glaze) 1140c (High Bisque) c (Mid Fire Glaze) 1300c (Porcelain) c (High Fire Glaze)