Flint Grey Underglaze

We have always used Ferro glazes (Ferro 6155 is what we use), as they seem to play well with Kiwi Underglaze! However, many people also use Amaco clear. In fact, we are not aware of any issues with any commercial glazes; quite often issues that have arisen in the past have related to home-made formulas.

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. 

Personally, 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 over 1,000 times safer than free 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 less 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. That 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 make sure the kids are supervised when using them. Having them test out whether yellow underglaze is banana flavoured isn’t going to be the best of fun!

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.