A great project for children, making pottery and glaze encourages creativity and fine motor skills. Unfortunately, many chemicals used in the process of making pottery are not child-safe. Teachers and parents who want to share the beautiful art of pottery with children can create their own child-safe glazes so that children can experience the joy of glazing their very own bowls and vases.
Choose a Child-Friendly Glaze Recipe
Pottery glazes have four basic components: glass-forming element, the refractory element, the flux, and the colorants or glaze modifiers. Of these basic components, the latter two are usually the most toxic because these are often metallic oxides. Some toxic ingredients to avoid include asbestos, barium carbonate, cadmium, all chromates, cobalt oxide, copper, ferrous sulphite, lead, and any kind of lead and uranium compounds. This is not a complete list by any means, but it does provide a good start when evaluating the ingredients in any glaze recipe.
Mix and Sieve the Ingredients
An adult equipped with a good protective mask should mix the ingredients. Even relatively non-toxic chemicals like silica are dangerous when inhaled. After measuring the ingredients according to the ratios given in the recipe, mix and add them to water. Always add the powder to water in order to avoid forming lumps at the bottom. Once the mixture gets to the right thickness—often described as the thickness of low-fat milk—pour it through a sieve to check for lumps. Sieve it several times.
Using the Glaze
Children can participate in this step, although wearing latex gloves is a good idea to avoid contact with the chemicals in the glaze. Be aware that the colour of the glaze is not the same colour that shows after the pottery is fired. Let it dry and fire it the kiln. At this point, proper ventilation is essential since many chemicals release toxic fumes when exposed to high heat.
Check for Defects
Creating a glaze, even with the help of a recipe, is a trial-and-error process. In fact, it may be a good idea to use the glaze on test tiles first before using it on pottery. Glaze defects like pinholes, crazing, shivering, and blisters point to different issues with the recipe that have to be corrected with more or less of certain ingredients. Adjust the recipe and try again until you have a child-safe ceramic glaze that produces the look you want.