Hopefully there are some ceramic gurus on here. I have bought a premixed stoneware glaze powder. It has directions to add 1 L of water and 0.5 L of pehatine (so 1.5 L water) to 1 kg of glaze powder (so 2.5 kg total). This would result in a specific gravity of approximately 1.67 (2.5 kg / 1.5 L).

I don't want to brush the glaze but pour and dip it, so I don't need the pehatine for that. I read that a specific gravity of 1.8 was pretty much the highest possible without using deflocculation.

I started mixing the powder with water only. I didn't power mix it, but just stirred it vigorously with a spork. I used 0.25 kg powder and 0.3 L water (specific gravity 1.83), so as not to have it too runny/watery. But already the viscosity is waay to watery (essentially runs like water).

I tried adding some vinegar to gel it, but not much happened, except after some time a part of the powder settles out of the slurry/solution.

What is wrong, how can my glaze have such low viscosity at such high specific gravity?

Am I calculating specific gravity correctly?

What is in pehatine exactly and what does it do?

Why doesn't the vinegar gel / slurry / fix the glaze?

  • 1
    I have no experience with glazing, but the product details of Pehatine advertise exactly that effect (last image on last page: left: dry powder; middle: powder freshly mixed with water and water-pehatine-mix; right: 2 hours later, container with water separated, container with pehatine didn't). A glaze is a powder suspended in water, so after a while the particles sink to the bottom and separate. Pehatine has something in it that makes the particles float for longer and separate less. To do that, it has to increase the viscosity of the slurry.
    – Elmy
    Jan 25, 2022 at 6:52


You must log in to answer this question.