Pottery/Multiple Glazes on Medium Clay Body
Hello, I am a novice ceramic sculptor, making pieces primarily to add to other sculpture, and am confused as to what I can do with glazing. I made a cone 5 clay turtle shell and bisqued to 04. I would like to fire the inside and lip with cone 5 glazes, then later do the outside with 04 or 06 glazes and refire. Will my cone 5 glazes melt and stick to the kiln or stilts when I refire ? If so, how about if I use glazes that fire to 016...would that work? I am trying to make pieces that are glazed all over and cannot figure out the logistics...except for using some underglazes with no flux but then there is no gloss or protection. Also (sorry) , do you know if a cone 04 or 016 glaze/luster will work on an outdoor piece when fired on a matured cone 5 or 6 clay body already partially glazed with cone 5 glazes? Hope this is not confusing....appreciate any help!
Dear P J,
Thank you for your recent questions. Let me begin by answering your very last question. Nothing you have given in your question is confusing. I have been doing this for a very long time and I am quite use to potters, ceramists and sculptors giving multiple questions in various order with detailed interpretation of their current situation, displaying exceptional artistic expression and thought as they try to convey a problem that is, to them, the ultimate wall between success or failure of their current project. Now that I have given you a "detailed" answer to your question, perhaps we can now tackle the remaining questions without regard to any worries you may have about how you depict your questions to me. <wink>
To answer your question on firing a lower maturing temperature glaze, such as Cone 04/06 on a Cone 5 fired piece, the Cone 5 glaze will not reach high enough temperature to cause a melt, however, there may be a bit of sticking with the glaze to the stilt points, but I highly doubt it.
I am concerned that you are wanting to use a Cone 04/06 glaze on a maturing Cone 5 clay. If you are creating a project that will be used outdoors, you will want to use a glaze that will not chip from the piece. Using a lower maturing glaze will not allow the glaze to fuse to the clay body as needed.
The purpose of using a matching glaze with a clay body is two-fold. First, the expansion and shrinkage of the glaze on the clay surface during firing and after the project is complete is essential to the strength of the structure. Second, a low fire glaze does not fire high enough to fuse to the clay body as a matching glaze body, therefore, the finished product is a product with two surfaces, the clay and the glaze, risking chipping and separation of the clay from the glaze over time. Using the appropriate glaze on the clay body will cause the fusion during firing to create a single surface, much like interlacing your fingers together. The only damage over time to the glaze will be surface damage from weathering and the glaze will stay attached to the clay body as required.
Finally, you asked if a Cone 04/016 glaze/luster will work on an outdoor piece of a matured Cone 5/6 body with a Cone 5 glaze. Yes, but as described above, it will not have the strength you want and will not last long in the weather elements.
My suggestion to you is to use Cone 5 glazes with the Cone 5/6 clay body. There are beautiful Cone 5 glazes available that you can mix yourself, if you desire to create your own glazes. There are also wonderful Cone 5 manufactured glazes you can use also. If you are wanting to use a luster glaze, I have some wonderful luster recipes I would be willing to share, if you give me a detailed list of what you are wanting the glaze to look like. I also have beautiful Cone 5 glazes I developed over the last 30 years that I would also be willing to share if you need any glazes for your project. But your best bet is to use a glaze that matches the maturing cone of the clay your are using to complete the project and make a sound and strong piece.
I hope this answers your questions. If you have further questions, please feel free to contact me again any time. If you are interested in any glaze recipes, please let me know what you are looking for and I will be happy to accommodate you. Much luck to you.
Ms. Ti Phillips
Earth Stoke 'N Fire Pottery Studio and Artist Retreat