Cone 6 Glaze Testing & Reporting

131 members

Description

Collaborate on building an online list of well documented glaze recipes, with application and firing methods. Strong photo documentation. Only glazes that are mature at cone 6 will be included.

Testing the glazes, and identifying their problems and fixing them. Also, if there are obvious issues just by looking at a glaze recipe (like high barium, insufficient clay to suspend or harden, too much feldspar (which causes crazing), too much clay (causing crawling, peeling), hard-to-get materials, non-specific materials, etc) then it needs to be fixed as part of the testing I would say.

Tony Hansen included links below to procedures for a few glaze tests that could be done. Another good one would be to appraise the rate at which it settles, how hard is the dry layer, the water content of the slurry, the viscosity, these could be measured with commonly available tools.

Links:

Thermal shock test

Melt flow test

Glaze hardness test

Glaze leaching test

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  • Joseph Fireborn

    I created the currie discussion board, lets move all future chat there. 

    Jun 6, 2016

  • Tom Anderson

    Hi George:

    I read through the posts/comments in this section, hopefully I did not miss any of them. The testing parameters shown are certainly welcomed and should be used by those mixing their own glazes.

    From some of the comments, I also noticed there was no discussion on glaze formulation criteria: unity formula, formula limits, and acid index. From the post on  the currie grid test: the SI/AL topic has not come up either. Everyone has their  own priorities for glaze mixing: for me it is SI/AL. Although I focus on crystalline glaze, I have spent a fair amount of time researching these glaze fundamentals.

    Also looked through the glaze recipe you referenced: as a rule of thumb any time I see a recipe with more than 70% flux I automatically check the COE. Even more so when sodium and potassium are the primary fluxes.

    Seeing as though this is a cone 6 dedicated site: I think it is important for members to know what fluxes are doing at this temp. Sodium and potassium are in a gaseous state at 2232F. Lithium, magnesium, calcium, and strontium are in a liquid state at this same temp. I am sure everyone has noticed that pin-holing almost always occurs when sodium and potassium are the primary fluxes in glaze; and in some cases the clay. Obviously there are many parameters governing this problem; but recipes with Na or K should always be suspect for the reasons stated.

    Tom Anderson

    Jul 24, 2016

  • Lawrence Weathers

    I have the GlazeChem database from about 2013. Tony says that I can upload it to Insightlive. Do you folks want me to do that via C6P.

    I have no idea what's in it since I don't have GlazeChem.

    Jan 28, 2017