Getting glazes to come out the same from batch to batch is a lot easier if you are sure the glaze is mixed to the same consistency each time. Many potters just eyeball it (you know, “mix to the consistency of skim milk”), but to get scientific, you need to measure the specific gravity with a hydrometer. Making a floating-stick hydrometer doesn’t have to be rocket science. While making calibrating marks on a simple soda straw to show the specific gravity does requires a bit of math, using a calibration chart (click link below!) makes it a lot easier to do. In today’s post, Roger Graham shows you how to make and use this simple tool. – Jennifer Harnetty, editor.