Low Fire Clear Glaze-Brushing

Preserve and enhance the surface of your work with Mayco’s Brushing Clear Glazes.

NT-BR, S-2101 and C-300

Our clear glazes provide a gloss or matte finish over top of your colored glaze decoration. Mayco offers three clear brushing glazes: NT-BR, S-2101 and C-300. Brushing glazes differ from dipping versions as they contain organic additives, making the brushing glazes thicker, more viscous than dipping formulas. The amount of glaze deposited on bisque is primarily a function of glaze viscosity and the amount of time the bisque is left in the glaze – careful attention to these two details are critical to obtaining satisfactory results.

Products

NT-BR Clear One Brushing

Fast drying and gloss finish. Compatible with Chrome Tin pigments and luster. Also available as a dipping glaze (NT-CLR).

S-2101 Crystal Clear Brushing

Clean, clear surface and gloss finish. Luster compatible. S-2101 may not be compatible with all red clays as a blueish haze may appear after firing.

C-300 Matte Transparent Brushing

Matte sheen at cone 06 and will gloss at higher temperatures. Luster compatible.

Low-Fire Clear

Clear glaze forms an impervious barrier that protects against liquids, dirt and abrasion.

General Use

Shake well. Apply one to two coats to shelf cone 04 (1060°C) bisque, unglazed or decorated with low fire glazes or underglazes. Dry thoroughly and fire to shelf cone 06 or 05 (999°C-1046°C). NT-BR and S-2101 will fire to a gloss finish. C-300 will fire to a matte finish.

ACMI CLFood SafeDinnerware Safe

All Mayco Brushing Clear glazes are AP Non-Toxic, Food Safe and Dinnerware Safe, when used according to manufacturer’s directions.

Usage Variations and FAQs

What is a clear glaze?

Clear glazes are glass coatings used to completely seal the ware (decorated or undecorated, making the ware impervious to liquids. They are also used to boost the brilliance of the underlying color. Clear glazes can come in different finishes such as gloss (NT-BR, S2101) or matte (C-300).

Should I use a dipping or brushing clear glaze?

Choosing a dipping or brushing version of a clear glaze is dependent on application preference, quantity of glazing and time. Mayco offers pre-made low fire clear glaze in both dipping and brushing formulas. Brushing clear glazes differ from dipping versions in that they contain organic additives, which make the brushing glazes thicker (viscous) than dipping formulas. These additives are meant to improve the flow of glaze from the brush and assist with the even-ness of application, enhancing the fired surface finish. The amount of glaze deposited on the ware is primarily a function of glaze viscosity and the number of applications. Typically, 2 applications are required, allowing dry time between coats. Dipping clear glazes contain fewer organic additives, making dipping glazes less viscous than their brushing counterpart. The amount of glaze deposited on the ware is a function of glaze viscosity and the amount of time left in the glaze. Often dipping glazes are preferred in a studio or production environment where a large quantity of ware is processed.

What does coefficient of expansion (COE) mean and how does it impact my choices of glazes, clay or bisque?

Glaze and clay/bisque bodies are both ceramic materials. During the firing process they expand and then contract together; the rate of expansion/contraction can be measured and mathematically stated as a coefficient of expansion.

Glaze and clay/bisque bodies are both ceramic materials. During the firing process they expand and then contract together; the rate of expansion/contraction can be measured and mathematically stated as a coefficient of expansion. If the two materials are not compatible – if they expand or contract at widely varying rates – the glaze may crack or chip off the body (please understand that incompatible COE’s are only one cause for glazes to chip or crack).

Mayco strives to produce glazes that are as tolerant of as many major sources of earthenware and stoneware bodies as is feasible. We stock over 20 types of clay bodies for testing purposes and glaze and fire samples from every shipment of bisque. But there are hundreds of clay bodies in use around the world, with hundreds of color glaze and clear glaze combinations being used on these bodies.

With respect to clear glaze: if you are experiencing an inordinate amount of shivering – glaze chipping off the body– you may want to try S-2000. If you are experiencing crazing – glaze in which cracks appear – you may want to try NT-CLR.

Occasionally I find hard, white pellets in my clear glaze. What are they?

Oolites are little pebbles of calcium carbonate. They form naturally although the exact reasons for their formation are unclear. With respect to clear glaze their occurrence is usually during the late summer months – the combination of the warm temperatures and vibration the glaze may experience during transit may factors. These materials can be strained out of the glaze using a fine mesh sieve.

The C-300 fired with a milky finish, what happened?

If the application of glaze is too heavy the C-300 will fire to a hazy/milky finish.

Are the brush on clear glazes luster compatible?

Yes, it takes on the finish of the clear glaze i.e. if applied to a gloss glaze it will be glossy, if applied with a matte glaze it will be matte.

C-300 did not fire matte. What happened?

Use witness cones to verify the kiln is firing to the correct temperature. This is the only way to verify the internal kiln temperature.

Can the brush on glaze be fired to cone 6?

It was formulated for a cone 06/05 firing. Mayco recommends the Stoneware line of clear glazes for higher temperatures.

I used S-2101 over the top of a red clay and it fired to a milky purple/bluish finish, why?

Mayco’s quality control with clear glazes are on white clay bodies. Iron Oxide reacts with clear glazes causing the tint.

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