Expansion Control - DeguDent Deguvest California Mode D'emploi

Avoid any nasty surprises by observing the following:
• Regularly check the temperature and humidity in the embedding region –
application temperature: +20 °C to +23 °C at 30 % to 90 % relative humidity.
• Avoid using any investment that has just been brought out of an especially warm or cold place .
(e .g . storage rooms, silos, cupboards etc .)!
• Fill up stocks at your workbench before your supply runs out . Give the investment time to adjust
to the environment!
• Avoid using investment that has just been delivered to the laboratory . Again, give the investment
time to acquire the right temperature .
• If space allows, stock up on investment (especially LIQUID) before the cold winter months arrive .
This way, you forego the risk of exposing the liquid to frost during delivery

4 Expansion control

To make the mould, the powder is weighed and mixed with distilled water . The expansion of Deguvest
California can be controlled by varying the amount of liquid added to the powder . This, in turn, compensates
the contraction of the casting alloy .
As a rough guideline the following contraction values may be taken in consideration:
– high gold-containing alloys (Au-Pt)
– gold reduced alloys (Au-Pd)
The total expansion, i .e . the sum of setting and thermal expansion, can be controlled by varying the
amount of distilled water added, in accordance with the table below . The less water used, the greater
the total expan sion of the investment compound .
Distilled water
32 ml
40 ml
12
GA_Deguvest California_50571812f_1215.indd 12
Setting expansion
(average)
0 .4 %
0 .1 %
approx . 1 .50 – 1 .58 %
approx . 1 .67 %
Thermal expansion
(average)
1 .2 %
1 .2 %
Total expansion
1 .6 %
1 .3 %
07.12.15 11:21