advanced violin restoration techniques - International Specialised ...

Attachments
PLASTER
Problems and solutions
Cause mixing container has been washed with a detergent
Solution always rinse the mixing container with clean water and dry it thoroughly
Cause water has been left over in the mixing bowl and therefore changes the
mixing ratio
Solution dry the container very thoroughly
Cause water that is too cold or too warm (40°C or over) has been used
Solution use water at room temperature
Cause plaster has not been mixed long enough
Solution follow the supplier’s instructions
Cause plaster has not been kept in a dry area and may have
absorbed humidity
Solution keep plaster in an air tight container, at an average temperature of 23°C,
and a relative humidity of about 50%
Fast or overaccelerated setting
Cause crystallized plaster particles are stuck in the mixing bowl or on
the utensils
Solution rinse the mixing bowl and utensils thoroughly immediately after use
Cause crystallization accelerator has been added to the water
Solution do not add products to accelerate the crystallization
Cause plaster has not been kept in airtight containers and has
absorbed humidity
Solution keep the plaster well protected from humidity
Cause water quantity has been underestimated
Solution keep to the exact proportions
Cause crystallized plaster particles have been mixed with the fresh plaster
Solution rinse containers and utensils thoroughly immediately after use
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