Powdered gum can be very difficult to disperse in water thus it is difficult to add it to an existing liquid batch. However if gum powder is mixed with other dry ingredients before adding them to the water it can be done (often 0.5-1.5%). A much more effective method is to boil water, add about 25-35 grams of powdered gum per litre and mix vigorously with a mechanical mixer (it should thin out over time). This mixture must be added during mixing to replace part of the water. It is difficult to set a standard proportion because the amount of gum needed is totally dependent on the glaze's ability to harden. A starting point for glazes that powder or smudge excessively might be 1 part gum solution to 3 parts water. Performance of the mix compared with the side effects can then be evaluated and the proportion adjusted.