what does sodium silicate do to pottery

The Secret Sauce: What Sodium Silicate Does to Pottery

(what does sodium silicate do to pottery)

Pottery making is an old art. It mixes creativity with science. One key material in this craft is sodium silicate. Many potters use it. But what does it do exactly? Let’s find out.

Sodium silicate is a chemical. People also call it water glass. It is a solution of silicon and sodium oxide. It looks like a thick, clear liquid. It dries to form a hard, glassy crust. This property makes it very useful in pottery.

1. What is Sodium Silicate?

Sodium silicate is a compound. It comes from sand and soda ash. Factories melt these materials together. Then they dissolve the result in water. The outcome is a syrupy liquid. This liquid is sodium silicate.

Potters buy it in bottles. They use it in its liquid form. When applied to clay, it dries fast. It leaves behind a brittle, shiny layer. This layer is key to its effects on pottery.

2. Why Use Sodium Silicate in Pottery?

Potters use sodium silicate for several reasons. The main reason is its ability to seal surfaces. It creates a barrier on the clay. This barrier prevents the clay from absorbing water quickly.

This sealing action is important for certain techniques. One popular method is called “crackle glaze.” Potters apply sodium silicate to leather-hard clay. The sodium silicate dries and cracks. Then they apply glaze over it. During firing, the glaze melts. It fills the cracks. This creates a beautiful pattern.

Sodium silicate also helps in joining clay pieces. It acts like a glue. But it is not a permanent adhesive. Its main job is to stiffen the clay surface. This makes attaching handles or other parts easier.

3. How Do You Use Sodium Silicate?

Using sodium silicate is simple. But timing is everything. Apply it when the clay is leather-hard. This means the clay is firm but still damp. If the clay is too wet, the sodium silicate will not form a good crust. If the clay is too dry, the crust may flake off.

Apply the liquid with a brush. Cover the areas you want to treat. Work quickly. Sodium silicate dries fast. You will see a shiny film form. This film will start to crack as it dries more. The cracks are what you want for effects like crackle glaze.

After applying sodium silicate, let it dry fully. Then you can apply your glaze. Fire the pottery as usual. The heat melts the glaze. It flows into the cracks made by the sodium silicate. The result is a unique, decorative surface.

4. Applications in Pottery

Sodium silicate has many uses beyond crackle effects. Potters use it to create texture. Apply it to clay. Let it dry and crack. Then brush off the loose bits. You get an interesting, rough surface. This surface can be glazed or left raw.

Another application is slip trailing. Mix sodium silicate with slip (liquid clay). Use this mixture for decorating. The sodium silicate makes the slip set faster. It helps the design hold its shape.

Sodium silicate is also good for repairing pottery. Got a small crack in your bisque ware? Dab a bit of sodium silicate on it. It can help seal the crack before glazing.

Some potters use it to resist glaze. Paint a design with sodium silicate. Let it dry. Apply glaze over the whole piece. The sodium silicate acts as a barrier. The glaze does not stick where the sodium silicate is. After firing, wash off the sodium silicate residue. Your design shows through.

5. Sodium Silicate FAQs

Is sodium silicate safe? Yes, when used correctly. Wear gloves. Avoid getting it on your skin. It can be drying. Do not ingest it. Keep it away from children. In the kiln, it burns away cleanly. It leaves no harmful residues.

How long does sodium silicate last? Store it in a cool place. Keep the bottle tightly closed. It can last for years. If it gets too thick, add a little water. Stir well.

Can I use sodium silicate on any clay? Yes. It works on earthenware, stoneware, and porcelain. The results may vary slightly. Test it on a small piece first.

Why is my sodium silicate crust flaking off? The clay might be too dry. Or you applied it too thickly. Try spraying the clay lightly with water first. Apply a thinner coat of sodium silicate.

(what does sodium silicate do to pottery)

Can I color sodium silicate? Not really. It dries clear. But you can mix it with colored slips. Or apply colored glazes over it. The effects come from the texture and cracks.