Low Fire Friday - A brief into to glazes and glaze mixing

Glaze – A Brief Intro

A glaze is glassy substance that has been adhered to the surface of ceramics through firing. It is made up of a glass former, a stabilizer and a flux. 

 The glass former is the glass. Typically this will be in the form of silica/flint

The stabilizer is what keeps the glass from completely running off of the ceramic piece.

Alumina is the main stabilizer and is found in clay.

The flux is an oxide (generally Alkaline) which causes ceramic fusion when combined with other oxides and heated.

Glaze recipes are usually written as a list with ingredients totaling 100%. This base glaze is usually clear/white. Any colorants, opacifiers, suspenders, and gums are written below the 100% line and are added as a percentage of the total glaze.

Base 4
Base Glaze	Frit 3195	65
	Gerstly Borate	10
	Wollastonite	15
	EPK	10
		100
	Bentonite	2
Colorants
Dark Brown	Red Iron Oxide	10

Glazes are usually measured and mixed by weight. However, any unit of weight can be used as long as it is constant throughout the entire recipe. I weigh my materials out in grams and typically mix a 500g batch (about the size of a large yogurt container). This means that I would multiply each material the recipe by 5. 

So, I would actually be measuring and mixing the above recipe like this…

Base 4
Base Glaze	Frit 3195	65	325g
	Gerstly Borate	10	50g
	Wollastonite	15	75g
	EPK	10	50g
		100	500g
	Bentonite	2	10g
Colorants
Dark Brown	Red Iron Oxide	10	50g

Water is added until the desired consistency is reached. This is a matter of preference and application technique. I brush my glazes on super, SUPER thick, so my glazes are usually about the consistency of Greek yogurt.

I hope this answered a few of your questions and will help get you started if you're new to glaze mixing. If you have any other questions, please feel free to comment or email me. 

Cheers!

Meagan