Page 115 - 20250602 EEA QM Edition 6.0

Quality Requirements Edition 6.0 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 The meaning of this specification sheet is to determine the slip properties by simple
density results from densities of the single components. Frit, quartz and clay have in methods. The equipment required is reasonably priced and easy to handle, though
average a density of 2.6 g/cm . There are also enamels available with a higher or always the sum of several flow parameters is registered.
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lower density. The frit supplier has this information. Water has a density of 1.0 g/ml.
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Colouring oxides have very different densities. They can be as high as 4 g/cm and With the described equipment, the following is obtained:
more. The small quantities of setting agents can be neglected by the calculation of
the density of slips. 1. Dipping test sheet or cylinder Yield point and Thixotropy
2. Enamel slip gauge Viscosity and Thixotropy
To predetermine the slip density, divide the sum of the weights of the single 3. Slump test Viscosity and Thixotropy
components by the sum of their volume. 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
The flow of a slip can be simulated with plane or shaped sheet sections. By weighing
Method of operation and 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
One Liter or a part of the slip can be weight out. Normally, the PEMCO density meter
application thickness of enamel. This test method is among other things affected by
with a volume of 100 ml is used.
varied manual draw-out velocities.

Method of operation:

A degreased test sheet of defined dimensions is dipped into the slip and withdrawn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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