Make your own brushable glazes

I am building up layers with different glazes on this large piece.

Brush on glazes are expensive but so useful!

Sometimes it is just easier to brush on a glaze when you have a very large piece and not much glaze or you want to layer up glazes or just to have more control and take you time where the glaze is going on the piece.

Great news! Any glaze can be made into a brush on glaze by adding a mixture of CMC and water. This can be done when mixing a new glaze from scratch by just replacing the water with a CMC mix by letting the mixed glaze settle and replacing the water with the CMC mix.

CMC is Carboxymethyl cellulose (CMC), or cellulose gum and it comes in a powder that you can mix with water to make a brushing medium.

Here is the recipe for the CMC mix

10g CMC

1.5 litres water

Blend the CMC into the water. Hot water and a hand blender can help with this process.

Leave the mix to age for at least 24-48 hours where it will become thinner.

How does it work?

When you glaze a bisque fired pot, the water from the glaze is drawn into the piece leaving the glaze on the surface. The addition of the cellulose gum slows down this process by briefly encapsulating the water and so the glaze can be brushed for longer.

Will it affect the glaze?

No the CMC will burn away on the glaze firing. You will need to experiment with how many layers you apply for the best effect and also apply consistent brush stokes for a smooth effect. I like to use 2” hake brushes for this.

You can get CMC from ceramic supply stores.

If you are in New Zealand - Botpots have the CMC https://www.botpots.co.nz/product/cmc-powder/

You could also experiment with wallpaper paste if you have some already.