Kiwi Underglaze is designed to work with a wide variety of clear glazes. Most commercial clear glazes perform well, though results can vary depending on clay body, firing temperature, glaze thickness, and kiln conditions. We always recommend testing your chosen glaze combination before larger runs, particularly when using homemade glaze recipes.

There is a small amount of flux in the formula, so out of an abundance of caution, we do not recommend putting it straight on the shelf in case it sticks. 

However, we do without any sticking issues! And we also have many customers who do. But to be safe, if you would like to - do a small test tile first.

Colour is brightest when clear glazed and fired to cone 4 or 5 (approximately 1180°C / 2150°F), but full glaze firing range is cone 04 to cone 9 (approximately 1050-1260°C / 1920-2300°F).

If you’ve finished your Kiwi Underglaze masterpiece with a durable clear glaze and fired it to the appropriate temperature (105 -1260 Celsius /1920 - 2300 Fahrenheit), congratulations—your creation is ready to shine at the dinner table! However, if you’ve opted for a matte finish without a clear glaze, we don’t recommend using it for food. Matte surfaces can be more prone to scratching, which could lead to bits of underglaze coming loose.

Lead-free zone! Kiwi Underglaze is 100% lead-free—always has been, always will be.

Vivid reds & oranges: some of these fiery shades contain encapsulated cadmium. This means that the cadmium is bonded with zirconium silicate, making it significantly less bioavailable than unbonded cadmium.

Silica superstar: silica helps give your finished glazes transparency, durability and stability, it’s amazing stuff! But it’s best kept in your glazes, not in the air where you can breathe it in. Luckily, our underglazes are liquid, which means no dust and less risk for you.

Our underglaze range is designed primarily for the midfire range. It has a wider range in which it will harden on and be foodsafe, but as with all things ceramics – whether it is clay, glaze or underglaze, you are going to get different colours at different temperatures. The boldest colour will be achieved at around cone 4-6 (midfire). This is where the colours really pop!

Our underglazes are for pottery pros, passionate hobbyists and budding artists alike, but please make sure the kids are supervised when using them.

When left unglazed and fired to around cone 06 (1000°C / 1800°F) or more, the colours assume a velvet matte appearance. This is a good surface for sculptural forms and as a decorating effect where glazing is not essential.

Yes. Kiwi Underglaze can be applied to leather hard clay or greenware. We recommend bisque firing to cone 06 (approximately 1000°C / 1830°F) before applying a clear glaze, as this generally provides the best adhesion and most reliable final results.

Sorry not just at the moment.

We use DHL Express for all our international deliveries. They're pretty speedy, but if you're really in a hurry, get in touch with us so we can discuss other options with you. Please also check out our Stockist Finder page for a stockist near you!

The company is located in New Zealand. We produce the underglaze at our facility near Hamilton, Waikato.

Cracking or flaking is most commonly caused by either applying the underglaze too thickly, or by dust, residue, or oils being present on the bisque surface.

Because bisque ware is very absorbent, it can be tempting to apply heavy coats to build colour quickly. However, underglaze shrinks as it dries, and overly thick application can lead to cracking, lifting, or poor adhesion.

We recommend testing with one, two, and three thin layers to find the best result for your particular clay body and firing temperature. Keep in mind that colour develops and intensifies significantly after firing, especially once a clear glaze is applied.