A hydrometer is a tool used to measure the specific gravity of a glaze, which will tell you how thick the glaze is.
- Thoroughly stir the glaze.
- Wet the hydrometer with a slightly damp sponge.
- Carefully lower the wet hydrometer into the glaze.
- Wait at least 15 seconds for the hydrometer to naturally settle into the glaze.
- Gently tap the side of the bucket a few times to make sure hydrometer completely settles
REMEMBER: Glazes will have different hydrometer readings. Here is the list of approximate measurements that our glazes should read on our hydrometer:
Liz Kraus Shino = 50
Rutile Blue = 50
Rutile Green = 49.5
Steve’s Copper Red = 52
Temple’s Persimmon = 46
Jeff’s Long Beach Blue = 53
IUS Celadon = 48
Monica’s Seafoam = 49
Iron Saturate = 48
Missouri Straw = 32
Mackenzie White = 50
Steven Hill Clear = 49
Cushing Satin Black = 52.5
Horsley’s Satin Matte White = 50
– If the number on the hydrometer is higher than listed above, add a little water and repeat the testing process until the hydrometer reads the correct number.
– If the number is lower than listed above, make a note on the bucket to have someone screen some water off the top of the liquid amount. (This of course has to be done AFTER the glaze has settled – usually after a day or so has gone by without anyone stirring the glaze). After screening some water off, then repeat the testing process until the hydrometer reads the proper number.
Here’s a Ceramics Arts Daily article on how to make your own hydrometer: HERE