I have been using commercial glazes lately, because I have been working out of my home studio since I bought myself a kiln last year. This has been working okay so far, and some of these commercial glazes will remain in my repertoire, but I really want to start making my own so I can tweak them to be exactly what I want.
But starting from scratch and figuring out what you need in your pantry can be pretty daunting. Not anymore thanks to Deanna Ranlett's article in the November/December 2013 issue of Pottery Making Illustrated. Today, I am sharing an excerpt from that article, along with a pretty handy materials chart showing how commonly certain glaze materials are used at various firing temperatures. - Jennifer Harnetty, editor.
Helpful Tips for Building Your Glaze Pantry
by Deanna Ranlett
Much like cooking, there are staples to any great glaze pantry. Having a stockpile of materials on hand opens your options to hundreds of recipes you’ll be able to mix in minutes.
A Good Foundation
It’s important to start your glaze pantry with a good foundation of commonly used glaze ingredients. There are specific lists for each range of firing temperatures: low fire (cone 08–02), mid fire (cone 4–6), and high fire (cone 8–10). Many ingredients are shared between the ranges, but some, like frits, you will use in a higher percentage at lower temperature ranges. Others, like stains, need to be tested at mid- and high-fire temperatures before stocking up on them as potential colorants.
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While it’s hard to recommend material quantities without knowing what batch sizes you’ll be mixing, I usually give the following guidelines:
If you’re mixing test batches, start with 5–10 pounds of the basics (feldspars, frits, kaolin, silica), ¼-pound bags of colorants, opacifiers, and stains, and maybe 1–2 pounds of rare ingredients. Planning ahead and buying in bulk may save you money in the long run.
If you’re mixing larger batches (5-gallon buckets), start with 50-pound bags of the basics, 5 pounds of Zircopax, ½–1 pound of oxides and common stains, and 5–10 pounds of less common ingredients. I’d recommend using a spreadsheet (see pdf attachment) or glaze calculation software to keep track of ingredients, amounts, and pricing.
Use this shopping list to help you get started at your local clay supplier. The list includes the essential materials you’ll want to start a glaze pantry and labels them as “common.” Those that are less needed but occasionally called for in recipes are noted as well followed by “occasional” or “rare”. Note: I have placed an asterisk (*) next to ingredients to buy in bulk if you’ll be mixing multiple batches or large 5-gallon buckets—although most ingredients can be purchased in various small quantities, 50-pound bags can save a significant amount of money. If it’s your first time mixing and you’re only mixing a few tests, a 5-pound bag would suffice.
Once you have the foundations of your glaze lab set up, you may want to consider adding a few additional items: a drill mixer for mixing large batches of glaze in 5-gallon buckets; an immersion blender for mixing small test batches; a rack or rolling cart to keep bulk ingredients off the floor; a sturdy table for mixing; glaze software; and a vent equipped with a dust filter. Have fun experimenting and building your glaze pantry!