Five Reasons to Convert Cone 10 Reduction Glazes to Cone 6 A Potter Shares His Rationale and His Recipes Rick Malmgren

There are a lot of traditional reduction glaze recipes out there, and they are typically formulated for firing at cone 10. But Rick Malmgren decided that he wanted to fire lower and still use a lot of these traditional glazes. So he set out to reformulate and adjust these cone 10 glazes to function well as cone 6 glazes.

What he found was that he not only saved time and money, but he also ended up with some gorgeous glazes.Today, Rick explains the benefits of firing lower and shares some of his great cone 6 reduction glaze recipes. - Jennifer Poellot Harnetty, editor

I have become a strong advocate of cone 6 reduction firing in recent years. My reasons are as follows:

• Lovely traditional glazes look as good as or better fired at cone 6 than they do at cone 10. Copper reds, Shinos, temmokus and dolomite mattes are virtually indistinguishable from their cone 10 brethren. Some cone 10 glaze recipes don’t even need to be adjusted— a few look just great at cone 6.
• Fuel savings amount to about 30% over a cone 10 firing. Granted, that isn’t much per firing (only the cost of two coffee mugs per kiln load, as Pete Pinnell once said), but if you are burning $2000 worth of propane per year, as I was a few years ago, it amounts to a nice $600 bonus at the end of the year.
• The savings in fuel costs is nothing, compared with the savings of time and energy. Being able to fire off a full kiln load in 7½ hours instead of the 10½ that it used to take me is where the real savings comes in. At cone 6, I can fire during the day and teach at night, on a more normal work schedule.
• Though I’ve fired my kiln more than 700 times, each ring takes its toll. The hotter it is red, the harder it is on the arch, the walls and the shelves. There is that much more expansion and that much more contraction, and that much more slumping. Cutting the temperature saves all the way around.
• Mountains of research have already been done for cone 6 oxidation, resulting in thousands of recipes. Oxidation potters have had to work hard with formulation to bring vitality to their glazes; they can’t depend on the atmosphere to do the work for them. Many of those same recipes fired in a reduction kiln are simply dazzling.

The following are my favorite cone 6 recipes.

 

**First published in 2010.