Use & technique
Which clear glaze works best with Kiwi Underglaze?
Kiwi Underglaze is compatible with most commercial clear glazes. The final result can vary depending on the clay body, firing temperature, and glaze thickness. Working with a new clear glaze or your own recipe for the first time? Always do a test tile first before starting a larger run.
Can I place my work directly on the kiln shelf?
Kiwi Underglaze contains a small amount of flux. In theory, this could cause pieces to stick slightly to the kiln shelf, but in practice most potters experience little to no issues. Not sure? Always fire a test tile first.
At what temperature or cone do I fire Kiwi Underglaze?
The full firing range runs from cone 04 to cone 9 (approximately 1050–1260°C). The most vivid and saturated colours are achieved at cone 4 to 5, around 1180°C. Outside that range, shades may shift slightly in tone or intensity, but they will never disappear completely.
Do I always need to apply a clear glaze on top?
Not necessarily. Without a clear glaze, fired to around cone 06 (1000°C), you get a beautiful matte, velvety finish. This is particularly suited to sculptural work or decorative pieces that will not come into contact with food or liquids.
Can I apply Kiwi Underglaze to greenware?
Yes — Kiwi Underglaze can be applied to both leather-hard and bone-dry greenware. For the best adhesion and most reliable results, we recommend bisque firing to cone 06 before applying glaze.
The underglaze is flaking or cracking after firing — what now?
This is almost always caused by applying the underglaze too thickly, or by dust, grease, or residue on the bisqueware. Make sure the surface is clean and grease-free, and apply several thin coats rather than one thick layer.
Safety
Is the finished result food safe?
Yes, when correctly finished. When the underglaze is covered with a durable clear glaze and fired within the recommended range (1050–1260°C), the pieces are food safe. Unglazed or matte-finished ceramics are not recommended for contact with food or drinks.
Does Kiwi Underglaze contain harmful substances or lead?
Kiwi Underglaze is 100% lead-free — and always has been. Some vivid red and orange shades contain encapsulated cadmium bonded with zirconium silicate, making them stable and safe when used correctly. As the underglaze is supplied in liquid form, dust formation and inhalation are not a concern.
Are the colours truly permanent after firing, or do they burn away?
The colours do not burn away. At midfire temperatures (cone 4–6) you achieve the deepest results. At higher or lower temperatures, shades may come out slightly lighter or warmer, but they will always remain visible after firing.
Is Kiwi Underglaze suitable for children?
Kiwi Underglaze is accessible for all ages and experience levels. As with any creative material, always keep an eye on children while they work.