Preparation of the material should involve following manufacture instructions. A paper pad or cool dry glass slab may be used for mixing the raw materials though it is important to note that the use of the glass slab will retard the reaction and hence increase the working time.[19] The raw materials in liquid and powder form should not be dispensed onto the chosen surface until the mixture is required in the clinical procedure the glass ionomer is being used for, as a prolonged exposure to the atmosphere could interfere with the ratio of chemicals in the liquid. At the stage of mixing, a spatula should be used to rapidly incorporate the powder into the liquid for a duration of 45–60 seconds depending on manufacture instructions and the individual products.[20]