Hydrometers are used to gauge glaze consistency. Buying a commercial one can be expensive. Here are some simple instructions on how to make your own for next to nix!

Difficulty Level: easy      Time Required: 30 min.

1. Get a piece of plastic or aluminium tube, about 8" (20 cm) long and 5/8" (1.5 cm) diameter
2. Insert a weight of about 10-20 grams, like a couple of ball bearings or even just some clay, into one end.
3. Temporarily seal both ends with a small piece of cork cut to the right size for a snug fit, but so you can get it out again.
4. Place hydrometer in a bucket of glaze to check whether it swims nicely, with the glaze level roughly between half way to two thirds up.
5. If it sinks too far, the weights are too heavy, if it swims too high, or doesn't remain stable, they are too light. Adjust accordingly.
6. Make a scratch in the shaft at the level of the glaze surface.
7. Remove from glaze, clean and continue making up to 20 marks, or however many are convenient, at 1/2" (1 cm) levels.
8. Number the marks from 0 to 20 (or up to however many you made), so that the lowest mark on the tube is 20, and the highest 1
9. Seal the ends of the tube properly with the cork and some superglue or other water impervious material.
   

1. Glazes with a higher density will have a higher reading and glazes with a lower density will have a lower reading.
2. Stir glazes properly every time otherwise readings may vary.
3. If a comparative reading is too high, you need to add water, if it is too low, you need to add more glaze powder.
   

Related Resources:

• The Glaze Page
• Glaze Calculation Programs
• Safety in the Studio