How to use KIWI Underglaze

Areas of use:

  • Applied to unfired, leather-hard clay, then raw fired, glossy glaze applied and glaze fired.
  • Apply raw fired clay, then glossy glaze and glaze fire.

Color and texture:

Kiwi underglazes have higher color intensity than many other underglazes on the market, and you can therefore brush thin coats at a time.

See tips for the best possible glazing here.

  • 1 coat = semi-opaque, 2 coats = more opaque, 3 coats = full coverage and most color.

The color becomes stronger and shinier when it is glazed and fired.

Without glaze, it gives a velvety matte surface, which is perfect for sculptural expressions.

Burning area:

Cone 04–9 (approx. 1050–1260°C). Brightest color around cone 4–5 (approx. 1180°C).

HEALTH AND SAFETY

At Scandiglaze we want to help you create amazing ceramics while staying safe and secure. With a little knowledge and care you can enjoy working with Kiwi underglazes without worry.

1. What do Kiwi underglazes contain?

Kiwi puts a lot of love into making underglazes, ensuring they are safe for everyday use. Like all ceramic materials, they require knowledge of handling.

  • Lead-free zone! Kiwi Underglaze is 100% lead-free – always has been, always will be.
  • Vibrant red and orange colors: some of these shades contain encapsulated cadmium. This means the cadmium is bound with zirconium silicate, making it over 1,000 times safer than free cadmium.
  • Silica: Silica helps give glazes transparency, durability and stability. We don’t want it in the air where you can breathe it in. Luckily, Kiwi underglazes are liquid, which means less dust and less risk to you. Just remember to work in a ventilated room if you’re going to scratch into dried underglaze.

2. Is it food safe?

Kiwi Underglaze is food safe when fired properly (like all underglazes). Finish your masterpiece with a clear glaze to make it food safe. If you have chosen a matte finish without a clear glaze, it is not food safe, but can be used for sculptures or other works that are not intended for food. Matte finishes can be more susceptible to scratching, which can cause pieces of underglaze to come off, which is why it is said to be not food safe without a clear glaze.

3. Cleaning and precautions

  • Keep it clean: wash your hands and wipe surfaces after using underglazes – they are not food safe in their raw form.
  • Good ventilation: work in a well-ventilated area, especially if you are going to spray the underglazes.
  • Mask: A dust mask is a must when sanding or spraying. If you have sensitive skin, you can also wear gloves. Wash your hands after using the underglazes.
  • Choose liquid: Kiwi underglazes are in liquid form, and the safest way to use underglazes.
  • Store smart: Store underglazes dry and away from direct sunlight.

4. Firing in the oven

  • Check your oven: make sure the elements are in top shape and make sure the oven is in a ventilated area.
  • Watch out for smoke: burning releases gases, so don't stay around the stove unless there is good airflow.

5. We love ceramics and the planet!

  • Dispose with care: When it's time to clean up, think about what's at the other end of the pipes. Try not to pour excess underglaze or rinse water down the drain. Instead, let the solids sink to the bottom of your container, carefully separate them, and dispose of them according to local waste disposal guidelines.
  • When it comes to spills, clean up with disposable cloths or paper towels, and dispose of responsibly.

6. Do you need more details?

Our Safety Data Sheet (SDS) has everything you need to know about composition, hazards and handling.

7. A quick reminder about use around children

Our underglazes are for passionate hobbyists, budding artists and professionals. If you work around children or have children who will be using the underglazes: make sure children are supervised when using them. Kiwi underglaze should NOT be eaten/drinked!

We are here to make your creative journey safe and fun.
Do you have any questions? Send us an email – we're happy to help!

About KIWI

Kiwi Underglaze is developed with a focus on quality, colour intensity and artistic freedom. The brand is known for its wide colour range and versatility – loved by professional potters and beginners alike. Combining reliable performance with creative possibilities, Kiwi offers products that are easy to use and deliver stunning results throughout the glazing process.

Kiwi Underglazes are manufactured in New Zealand. The company has been making pottery for over 20 years and is a well-known brand on the other side of the globe.

Kiwi underglazes – a colorful and versatile series with 50 shades that suit both colorful and subtle expressions.

Frequently asked questions

What is underglaze?

Underglaze is a type of ceramic color that is applied before the clear glaze and glaze firing. It allows you to paint detailed designs on your pottery and is more durable than brush glazes, as the clear glaze over it protects the design. Unlike regular glaze (brush glaze), underglaze stays where you paint it, without flowing out, making it perfect for precise designs and patterns.

What is the difference between glaze and underglaze?

Glaze provides a glossy, glass-like protective surface and can flow together during firing, creating great variations in color and expression. Underglaze is designed for painting and detail work and stays where you place it, as well as allowing you to mix colors in a more precise and controlled way. You can use glaze alone, while underglaze should be topped with a clear glaze to protect the design and make it food-safe.

Is KIWI underglaze more expensive than other brands?

No, on the contrary! When you compare price per ml, as you do when buying food (kroner per kg/liter), we see that KIWI is actually cheaper than most other brands on the market. We have checked all the competitors' prices and sizes. What we see is that our 100ml bottles, at 1.40kr per ml, are one of the most reasonable on the market. Other brands' underglazes (from 59 ml to 118 ml) cost between 1.50-2.00kr per ml. With KIWI you get more underglaze for your money, plus the fantastic quality and color variation that makes every kroner count extra. It's just like choosing the big yogurt box in the store - you get more value per kroner. The bonus of the larger size of the bottles is also that you don't have to run out of your favorite color in the middle of the project!

At what temperature should I fire KIWI underglaze?

KIWI underglazes have a firing range of 1050 to 1260°C (cone 04 to cone 9). The colours are most vibrant when fired to cone 4 or 5 (approx. 1180°C) with a clear glaze over them. At ScandiGlaze, all underglazes are fired to 1240°C.
They work well at both stoneware and earthenware temperatures. Be aware that some colors may fade at higher temperatures, so always do test firings before embarking on larger projects.

When should I apply underglaze - on unfired or raw fired ceramics?

KIWI underglaze can be applied to both unfired ceramics (greenware) and unfired ceramics (bisqueware). You have several options:

  • Application to unfired ceramic, then raw firing at cone 06 (~1000°C) before application of clear glaze and glaze firing.
  • Application to raw fired ceramic, followed by clear glaze and then glaze firing.
  • Application to raw fired ceramic, followed by an optional additional raw firing at cone 06 (~1000°C) to "harden" the color before glazing and glaze firing.

Do I need clear glaze over the underglaze?

For best results and durability, we recommend a clear glaze over KIWI underglazes. After firing, the colors become more intense. When the underglaze is covered with a clear glaze and fired to cone 4 -5 (approx. 1180°C), the colors are at their most vibrant. FYI, our own works under the “inspiration” tab are fired at 1240°C.

Without a clear glaze and fired to around cone 06 (~1000°C) or more, the colors have a matte, velvety surface that is beautiful for sculptural forms and decorative effects where glazing is not necessary. Please note that you must have a clear glaze over the underglaze for it to be considered food safe!

Can I mix KIWI underglaze colours?

Yes! This is one of the great advantages of underglaze - you can mix all the colors to create your own unique shades. Unlike regular glazes, which are often not mixable, underglazes give you total freedom to experiment with colors.

Is KIWI underglaze safe to use?

KIWI underglazes are 100% lead-free and always have been. Some vibrant red and orange shades contain encapsulated cadmium, which means the cadmium is bound with zirconium silicate, making it over 1000 times safer than free cadmium. The glazes are completely safe to use in their liquid form.
For safe use: wash hands and wipe surfaces after use, work in well-ventilated areas (especially when spraying), wear a dust mask when sanding or spraying, and store bottles tightly closed in a dry place away from direct sunlight.

Why is my underglaze becoming cloudy or spotty?

This can be caused by several things: too thick an application (use thin layers to avoid cracking or flaking), dirty brush or sponge (always use a clean brush), or the underglaze was not well mixed (always mix thoroughly before use as underglaze can separate over time). KIWI underglaze bottles are shaken well before use.

Apply the color as thinly as possible in layers to achieve the desired effect. Allow the underglaze to dry completely between each layer and before applying the clear glaze.

Can I apply more underglaze after the raw firing?

Yes! This is one of the advantages of KIWI underglaze. You can apply underglaze to unfired pottery, raw fire it, and then add more color and detail before applying clear glaze and firing again. This gives you the flexibility to build up designs in layers.

Where did my discount code go?

First, check if you received an email from us that ended up in your junk or spam folder.

If you don't find it there:
Contact us at hei@scandiglaze.no and we'll fix it!

Which glossy glazes do you recommend?

We’ve tested the following clear glazes over KIWI underglaze:

  • 1091 Porcelain Glaze (dipping glaze)

  • Amaco Mixing Clear Gloss (brush-on glaze)

  • Botz Transparent Glaze (brush-on glaze)

  • Amaco Clear Zinc-Free (brush-on glaze — useful on dark clay)

There are of course many others that will work as well, so we highly recommend making your own test tiles and firing them in your kiln using your own firing schedule.