Period ____# _____ Name ____________________________ Date _____________ GLAZING 101 Glazes are thin layers of glass fused to the surface of ceramic (clay) bodies. They are composed of glass forming minerals (silica); fluxes (melting agents); clay, which gives body and helps control flow or viscosity of the glaze; and colorants if color is desired. Examples of colorants are iron oxide or cobalt. Glazes may be colored or clear; bright or dull; transparent, translucent, or opaque. Glazes can be glossy or have a semi-gloss, semi-matte, or matte appearance. Wet glaze is applied to a clay surface and when dried forms a powered layer. Glaze is applied by dipping, pouring, brushing or spraying. Most often we will dip or pour glaze on. *** IMPORTANT THINGS TO REMEMBER *** Glaze is applied to work that has been bisque fired (in most studios). Avoid handling bisque fired work too much (oil from your hands can affect glaze). Bisque fired work is still fragile – avoid using handles on cups until final firing. Once work has been glazed put it on the “To Be Glaze Fired” rack. It is very important to not put glaze on too thick. It is very important to not have any glaze on the bottom of a piece. Clean up any equipment you use: mixers, brushes, cups for pouring. Low-fire glaze is generally fired to a temperature range of 1600 - 2000˚ F. Some low-fire glazes (like luster glazes) are fired to a lower temperature. We will not be using low-fire glaze. We use High-fire glaze that is fired to Δ5 - 2151˚ Fahrenheit. Other glaze materials available are underglazes and oxides. BE EXTREMELY CAREFUL TO NOT CONTAMINATE GLAZES!!!!!!! If you are not paying attention you can easily pour the wrong glaze into the wrong container, put a brush in the wrong jar…. BE CAREFUL!!!!! Period ____# _____ Name ____________________________ Date _____________ GLAZING PROCESS 1. Use a damp sponge to get rid of any unwanted dust or oil which will prevent the glaze from sticking to the surface. You must be careful not to have oil or dust on your hands as you handle the unglazed pieces. 2. Apply wax resist to anywhere you do not want the glaze to be. Glaze will attach areas that it touches together. It is also wise to put the wax ¼" up the side of the pot too minimize glaze runs or drips. Let the wax dry (5 minutes) before going on to step #3. (Use the banding wheel to apply an even coat that has a clean line.) 3. Prepare the glaze by making sure it is totally stirred up as many of the glaze elements tend to settle. Also see if there is enough glaze available for what you are doing. Use clean tools when glazing (stirring utensils, pour cups, bowls, buckets, and dipping tongs). Do not mix the glazes together as they will contaminate each other and become unusable! 4. Apply the glaze. Glaze application will greatly affect the outcome. The most common method will be dipping and pouring. Pour glaze on inside, turn pot and pour out glaze (covering all inside). Dip piece in glaze (for 2-3 seconds) remove and shake off extra Cover any finger prints by dabbing glaze with finger tip (or brush). Clean off any drips or excess glaze (especially on bottom.) Glaze should be about 1mm thick (thickness of a fingernail). Underglazes are applied with a brush and 2-3 coats are applied. Glaze that is applied too thick may crack and fall off your piece. If you need to re-glaze a piece before it is fired; wash it off completely and let it dry at least 24 hours and try again. Glaze can be applied by brushing, spraying, pouring, and dipping. A combination of techniques can also be used. Glaze can be applied one over the other if allowed to dry in between applications. (Colored oxides can also be used under or over the glaze for added color and effect.) Continue to handle your piece with care as the glaze dries to a powder, do not touch other pieces if you have powdered glaze on your hands. 5. Clean any glaze off the foot of your work (dry-footing). Make sure no glaze is on a contact point, for example where a lid fits on a jar. 6. Place your work on the “To be fired” rack – and wait for it to be fired!