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2019-10-16
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Investment material
Generally, there are three types of investment:
Gypsum-bonded
investment materials for metal temperatures up to 1250 °C. (Flask tem-
perature up to 730 °C) These are standard investment materials for gold, silver, bronze,
etc. These investment materials are stirred with water and the investment is easy to re-
move by quenching in water.
Phosphate-bonded
investment materials for higher temperatures
These investment materials are applied with water and are suitable for metals up to
2000 °C metal temperature (flask temperature up to 990 °C), ie for steel, palladium 950,
platinum. These investment materials are stirred with water.
Disadvantage: Most difficult to remove. After pouring, the cuvette is to cool and the in-
vestment mass is then coarsely removed with a hammer. A sand blasting machine with
corundum medium is very helpful.
Due to legal regulations, it is not advisable to use acids to clean the castings.
Dental investment
materials usually have especially good properties in terms of shrink-
age and shape contrasts. These investment materials are often mixed with acid.
Disadvantage: Very expensive. Most difficult to remove. After pouring, the cuvette should
cool and the investment mass is then removed roughly with a hammer. A sand blasting
machine with corundum medium is very helpful.
Due to legal regulations, the use of acids for cleaning the cast trees is not advisable.
Each manufacturer has a variety of investment materials in the program. This means that
comprehensive information about the properties is necessary. Your specialist dealer can
be a suitable contact person. Please read the instructions carefully for use so that im-
portant details such as mixing ratio, water temperature and processing times are meticu-
lously strictly adhered to. Investment compounds should only be purchased from reputed
traders. Investments have a limited life.
Investments are all hydrophilic, that is, open containers accumulate with moisture. A good
solution: store the embedding embedding compound in chemical whiskey bottles. A few
dry bags (as in packs of electronic devices) help here.
Investments are a mixture of different powders. A long transport with the ship or truck can
change this mixture. Heavy parts sink down, light parts float on top. In production compa-
nies, whole containers are often homogenized in a cement mixer. It is also sufficient to put
the drum upside down and shake it.
