Page 112 - QRedition5.0 062021

Quality Requirements Edition 5.0 European Enamel Association

8.5.4.2 Determination of the density of slips 8.5.4.3 Determination of the flow behaviour of enamel slips by simple methods

Purpose and scope Purpose and scope
The density or specific gravity is the weight of one liter of slip in kilogram. The slip density The meaning of this specification sheet is to determine the slip properties by simple
results from densities of the single components. Frit, quartz and clay have in average a methods. The equipment required is reasonably priced and easy to handle, though always
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density of 2.6 g/cm . There are also enamels available with a higher or lower density. The
the sum of several flow parameters is registered.
frit supplier has this information. Water has a density of 1.0 g/ml. Colouring oxides have very

different densities. They can be as high as 4 g/cm and more. The small quantities of setting
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With the described equipment, the following is obtained:
agents can be neglected by the calculation of the density of slips.

1. Dipping test sheet or cylinder Yield point and Thixotropy
To predetermine the slip density, divide the sum of the weights of the single components
2. Enamel slip gauge Viscosity and Thixotropy
by the sum of their volume.
3. Slump test Viscosity and Thixotropy

4. Outflow cup Flow in pipes
The fineness of grinding of the slip has no influence upon its density.

1. Dipping test and dipping cylinder
Method of operation
One liter or a part of the slip can be weight out. Normally, the PRINCE density meter The flow of a slip can be simulated with plane or shaped sheet sections. By weighing and
with a volume of 100 ml is used. conversion into one square meter of surface, the amount of slip left on the to be enamelled
part is obtained. This amount permits an estimation of the subsequent application thick-
ness of enamel. This test method is among other things affected by varied manual draw-out
velocities.

Method of operation:
A test sheet of defined dimensions is dipped into the slip and withdrawn obliquely. After
the excess slip has drained off, the amount left on the sheet is determined by weighing.
Since the area of the sheet is readily measured, it is easy to calculate the specific amount
applied.

There is no need for any calculation if the same sheet is used frequently. Then the applied
weight is a direct measure. For external use, the application weight has to be expressed
in g/m , because the size of the test sheet is unknown to the interlocutor. In order to fit a
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