Cone 5 clay fired to cone 6 to accommodate a cone 6 glaze

[Kristine]

I have recently set up my own studio, but lack knowledge in the area of firing . I have found some great cone 6 glaze recipes but have not been able to find a commercial cone 6 clay. Before I experiment and do something which might damage my kiln I wonder if anyone has any experience in doing this. It is my understanding that the cone 5 clay would likely fire to cone 6 and worst case scenario I might have some warping. Any recommendations?

[neilestrick]

Most cone 5 clays, although not labeled for cone 6, will work just fine. Ask the manufacturer to be sure. Also, most cone 6 glazes will work fine at cone 5.

[perkolator]

best thing to do is probably to perform a test and see how it goes so you know exactly how YOUR setup acts. we can tell you all sorts of things, but until you do it yourself you won't know for sure. I am fairly confident you will not ruin your kiln doing this test - if you ARE worried about experimentation, it's not a bad idea to build yourself a saggar or firing trays (FIRED FIRST to ensure crack-free) to test your things inside and keep mishaps fairly contained should the occur.

 

personally, i consider ^5 and ^6 sorta interchangeable as "mid range"since they are fairly close together temperature-wise. I guess it'd really comes down to how your clay acts at the hotter temp as well as the needs of your particular glaze. It's fairly common for a kiln to fire hotter on top since heat rises, and it can be as much as a cone's difference depending on how the kiln fires. I'd also assume a commercial clay is formulated to be slightly forgiving in terms of 1-2 cone difference - but then again some clays will slump at the temp indicated on the label, it all depends. You're also not specifically limited to a ^5-6 clay - lots of people who fire to mid-range still use stoneware clay body (depending on what you're doing of course!). Same goes for glaze - some work great at either cone, just depends on the glaze.

[Pam S]

I too use cone 5 and 6 interchangeabley. I also find some 6 glazes perform better for me at cone 5 and visa versa.

[Radagast97]

I agree with the previous posters, most cone 5 clay's should work, but also remember that different parts of your kiln may fire differently. It's not unusual to get a cone 5 at the one part of the kiln and 6 1/2 in a different part. Be sure to use a few cone packs to ensure you know what all the parts of your kiln are firing to.