Sculpturezsil Posted August 21 Report Share Posted August 21 Question. (I'm new with ceramics.) Normally speaking when I have my clients make any projects, they use underglaze and clear glaze after. The first bisque firing is done at Cone 04 at slow speed and cone 06 at med speed for the clear glaze. I recently was given new glazes that say they need to be fired at cone 5 or 6. I'm wondering can I use these kinds of glazes on clay that is first fired at 04? Will it be okay in the kiln or do I need mid-fire clay for cone 5/6 glazes?? Quote Link to comment Share on other sites More sharing options...
Hulk Posted August 21 Report Share Posted August 21 Is the clay mid fire, cone 5/6? What is the indicated firing range? Clay designed for cone 04 could melt and make rather a mess if pushed to cone 5/6. Glazing cone 5/6 clay wares that have been first fired to cone 04, then glaze firing to cone 5/6, that's normal. Some potters first fire a bit warmer, some a bit cooler*. Clays and glazes designed for about the same firing target, good idea. *Some potters glaze raw clay wares and fire just once! Bill Kielb, Pres and PeterH 3 Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted August 27 Report Share Posted August 27 You definitely don’t want to use cone 6 glazes on clay that is supposed to be fired at cone 06! If you fire the glazes to maturity, the clay will likely be a puddle. When looking at the numbers on Orton cones, the 0 is like a decimal. So cone 06 is a lot cooler (relatively speaking) than cone 6. Cones measure melt, so there’s time and temperature ratio involved. but cone 06 is about 1816 F, cone 04 is about 1922 F and cone 6 is about 2194 F. Pres 1 Quote Link to comment Share on other sites More sharing options...
Pres Posted August 27 Report Share Posted August 27 Check an Orton cone chart to realize the differences in the cone numbers. Realize then that clay manufacturers use different formulas to manufacture clays that fire at different temps. This is because the clay matures/vitrifies at different temps depending on the formula for the clay. best, Pres Callie Beller Diesel 1 Quote Link to comment Share on other sites More sharing options...
Denice Posted August 27 Report Share Posted August 27 I have been around kilns that had low fire clay and high fire glaze. One was a electric the pots melted into a puddle, the other was a gas firing C10 the pots turned into a liquid and dripped all over the other work and shelves. Denice Pres and Callie Beller Diesel 2 Quote Link to comment Share on other sites More sharing options...
Chilly Posted September 1 Report Share Posted September 1 As above, plus, if you fire the ^6 glazes to ^06/04, the glaze will not mature. It will likely be matt, rough, chalky. To be brutal - it will be ugly. Pres and Callie Beller Diesel 2 Quote Link to comment Share on other sites More sharing options...
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