More problems measuring glaze specific gravity using a hydrometer

Wednesday 16th January 2019

Potters sometimes call this a "floating thingy". Maybe, because of the problems it presents, it does not make a big enough impression to remember the name! Because of the length of the hydrometer the only container we have is this graduated cylinder. I have to fill it just the right level so it reads near the top. OK, fine. But the hydrometer needs to bob up and down to find home. However, this glaze has our desired thixotropy, which prevents free movement. OK, I will carefully help it find home by pushing it down a little. But then it doesn’t want to bob back up! Ok, I’ll pull it up ... then is doesn't want to go back down to where it should float. Not great. Next problem: The glaze is opaque, I can’t see the reading. Yikes! A better way would be to throw out the hydrometer and just tare the empty cylinder on a scale, fill it to 100 and read the SG as the weight/100. Or fill it to any mark and divide the weight by that.

Pages that reference this post in the Digitalfire Reference Library:

Measuring glaze slurry specific gravity, Specific gravity - Viscosity, Thixotropy

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