Although Phoenix Red is designed to be a low-fire glaze, it is stiff enough to successfully fire to Cone 5. I had fun testing this glaze alone to cone 5 on various clay bodies and also testing it on top of other glazes designed for mid-range stoneware. Anytime I push the limits of a glaze, I test it on the inside of a bowl. This lets me see how well the glaze will withstand the excessive heat while not ruining a kiln shelf (sadly, i learned this lesson the hard way…three times)
With Phoenix Red, I found that it was still very stiff and even semi-matte at the higher temperature. The main difference was in the color. At cone 5, the glaze is a more muted almost mauve color, and where it is thicker, it gives hints of purple. When used in combination with other glazes, the effects were downright stunning!
I just love the versatility of this glaze, especially for someone like myself who works at a variety of temperature ranges.