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  1. Hello! I have been harvesting a beautiful blue marbled clay, processing it, and then making cups. I did a test-bisque at cone 04 which turned out great, but the low-fire glaze that I applied afterward (cone 05-06 glaze) did not absorb easily and took several hours to dry. Is it worth trying to fire it anyways? And in the future: Will I run into complications if I bisque at a lower temperature (cone 05-08?) then apply glaze and fire at 05? The glaze directions say to bisque at cone 04, but I'm assuming its not necessary if the clay I'm working with is extremely low-fire? Thanks for the help! I am a beginner ceramicist working at home with access to a community kiln. I have never worked with locally harvested clay before and its amazing but difficult to figure it all out.
  2. Thanks for the help and clarifications-- I do mean cone 04/05/06 (would bisque at cone 04, then pit-fire, then apply a food safe low fire glaze and fire in a kiln at cone 05) I will experiment using this process and several types of clay (one that I've harvested and another standard grey clay) and post the results. I do not expect most of the coloration from pit-firing to stay, but am curious to see what the results are anyways.
  3. Ok, so I have an earthenware glaze that is food safe and low fire (cone 5 or 6) so I'm wondering:: If I bisque at cone 4, then pit fire, then glaze and re-fire in the kiln at cone 5, will it still keep the coloring from a pit-fire? Thanks for help!
  4. I mean food safe-- they will be used for drinking water from.
  5. I have not tested the blue clay yet and will need to do that as soon as its dry enough to work with.. Thanks for the help! I also reached out to another professional ceramicist who had this to say: I never make any guarantees about predicting what clay may or may not do. It continues to surprise me all the time and I encourage experimenting. Presumably if you are firing a stoneware clay to high temperatures (i.e. Cone 8-10) then you are vitrifying the clay and it isn't going to change significantly in a lower temperature firing environment. That being said, a pit fire may be a reduction atmosphere and cause the clay to go black or purple. Also, any soluble salts that could be introduced due to the fuel or soil might cause further color changes. Keep in mind if a clay body is vitrified then it can be food safe without a glaze and that just because a glaze is high fire doesn't necessarily mean it is food safe. Also:: I'm wondering if it might be possible to just seal the pit-fired cups with something to make them water-safe..? Was looking into Tung Oil, but ideally it would be something that doesn't wash off easily.. Thoughts?
  6. Hello! Is it possible to high fire a glaze on the interior of a cup and around its lip, and to then pit fire? I'm trying to find a way to make pit-fired cups food/water-safe! I'm assuming that this process wouldn't affect the high-fire glaze, but perhaps the outside (unglazed) body would no longer be able to take in the marvelous colors produced in a pit fire? I'm new to this process, but will be doing a ton of experimenting over the coming months with local blue clay that I've begun harvesting. Thanks for any insights!
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