Dani dowling Posted July 12, 2022 Report Share Posted July 12, 2022 (edited) Hi guys! I am new to pottery and keep experiencing issues. I have success when I bisque fire, and SOMETIMES success when I glaze fire. Sometimes I have shivering or crazing but not all the time, and I'm always using the same glazes. Which leads me to believe it's an error on my end or how I'm running the kiln. Anyways I spent days glazing these little owls and all of them came out shivering so bad and also they were matte and not shiny and the color is completely off. Something went wrong just not sure what. Any and all advice is appreciated again I am SUPER new at this so please be kind. I am using sax true flow ceramic glaze. Edited July 12, 2022 by Dani dowling To add a photo Quote Link to comment Share on other sites More sharing options...
Min Posted July 12, 2022 Report Share Posted July 12, 2022 Hi Dani and welcome to the forum. 18 minutes ago, Dani dowling said: Anyways I spent days glazing these little owls and all of them came out shivering so bad and also they were matte and not shiny and the color is completely off. Something went wrong just not sure what. Any and all advice is appreciated again I am SUPER new at this so please be kind. I am using sax true flow ceramic glaze. Couple questions about your firing. Did you use witness cones on the shelf(ves) you fired the owls on? Manual kiln with a kiln sitter or electronic kiln? The fact that they came out matte and not shiny (given you used a gloss glaze) would more than likely mean they are underfired. If this is the case you can refire them to the correct cone. 21 minutes ago, Dani dowling said: Sometimes I have shivering or crazing but not all the time, and I'm always using the same glazes. If the glaze is underfired and immature it isn't giving you optimum results. If the glaze is fired to maturity and you are still getting either crazing or shivering that would mean the glaze doesn't fit the clay it's on. It is highly unusual to get both shivering and crazing of a glaze but it is possible to have an underglaze shiver and a glaze craze. Quote Link to comment Share on other sites More sharing options...
Pres Posted July 12, 2022 Report Share Posted July 12, 2022 @Dani dowling, is there any glaze on the shelves around the pieces? best, Pres Quote Link to comment Share on other sites More sharing options...
neilestrick Posted July 12, 2022 Report Share Posted July 12, 2022 Shivering and crazing are opposites. In shivering the clay is shrinking more than the glaze, in crazing the glaze is shrinking more than the clay. So for both to happen to the same glaze would be very unusual unless there's some sort of inconsistency in the batch of clay. What cone are you bisque firing to? What cone are you glaze firing to? Rae Reich and Pres 2 Quote Link to comment Share on other sites More sharing options...
Dani dowling Posted July 18, 2022 Author Report Share Posted July 18, 2022 Thank you for your response, and I really don't know what I'm talking about I'm totally new to this so I think right now I'm just mainly dealing with the shivering. So far 3 glaze fires in a row this has happened. I'm wondering if the pieces I Bisqued didn't bisque enough or something? Cone 08 Quote Link to comment Share on other sites More sharing options...
Dani dowling Posted July 18, 2022 Author Report Share Posted July 18, 2022 (edited) Would I be able to add feldspar powder to my already made sax trueflow glaze to avoid shivering? Cone 08 Edited July 18, 2022 by Dani dowling Quote Link to comment Share on other sites More sharing options...
Hyn Patty Posted July 18, 2022 Report Share Posted July 18, 2022 Wait, you /only/ bisque fired to cone 08? That's a pretty low fire to bisque even earthenware. So of course we want to know what clay you are using. Even earthenware usually bisques to at least cone 06 and better if at 04. So that is a possible issue even before you added your underglaze and clear glaze if you aren't bisque firing to maturity first. Definitely sounds like you are underfiring but we need more information. Quote Link to comment Share on other sites More sharing options...
PeterH Posted July 18, 2022 Report Share Posted July 18, 2022 41 minutes ago, Hyn Patty said: Wait, you /only/ bisque fired to cone 08? That's a pretty low fire to bisque even earthenware. So of course we want to know what clay you are using. Even earthenware usually bisques to at least cone 06 and better if at 04. So that is a possible issue even before you added your underglaze and clear glaze if you aren't bisque firing to maturity first. Definitely sounds like you are underfiring but we need more information. 9 hours ago, Dani dowling said: Would I be able to add feldspar powder to my already made sax trueflow glaze to avoid shivering? Cone 08 Having difficulty finding the full firing range for "sax trueflow glaze", but this https://www.amazon.co.uk/Sax-True-Flow-Gloss-Glaze/dp/B0044SCR6O says Dinnerware safe when fired to cone 06-05 (so cone 08 seems low). Quote Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted July 18, 2022 Report Share Posted July 18, 2022 Without knowing the composition of the glaze, you can try altering the glaze with additional ingredients but it’ll be a random guess if it’ll work, and you’ll void any warranties from the manufacturer. And typically, adding feldspar isn’t a remedy for fit issues in any case. If you’re working with a commercial glaze, you’re better off asking your clay supplier what they recommend. They’ll know which clay/glaze combos work the best. Quote Link to comment Share on other sites More sharing options...
Babs Posted July 18, 2022 Report Share Posted July 18, 2022 (edited) @Dani dowling A re you damp wiping your pots to get rid of dust prior to glazing? Are youR hands oil free? Are you measuring temp/ cone your kiln is reaching with cones? Is this happening all over your kiln shelves, every firing or what? Cone 08 is way low for a bisque or a glaze firing. What cone are your glazes maturing at? Dull unshiny glazes often means required maturation cone not reached. What is your firing schedule? Start making a log book recording your firings and results. Exciting, eh? Edited July 19, 2022 by Babs Quote Link to comment Share on other sites More sharing options...
Bill Kielb Posted July 18, 2022 Report Share Posted July 18, 2022 (edited) Sax trueflow glazes fire from 06 to cone 6, much like stroke and coat. Sort of a lowfire glaze that can survive midfire temperatures. They finish glossy and my guess is they need to be fired to cone 06 minimum to melt. Cone 08 is uncommon so I think to solve this you will need to answer or get the answer to many of the questions above. What is you clay, do you fire using witness cones, etc….. Glazes such as this often contain lots of boron but are quite high in alumina and silica or fairly stiff as they say. Adding things probably won’t help. Firing this to 06-04 likely gets it glossy and maybe an even better fit. Among many questions - what does your clay mature at? Hey just thinking, cone 04 is hotter than 05 is hotter than 06 …. Sort of like on the negative side of the number line. Not sure if anyone has explained this to you. If you know it already, apology in advance for assuming. Edited July 19, 2022 by Bill Kielb Quote Link to comment Share on other sites More sharing options...
neilestrick Posted July 19, 2022 Report Share Posted July 19, 2022 @Dani dowling what clay body are you using? Are you bisque firing and glaze firing to cone 08? Quote Link to comment Share on other sites More sharing options...
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