Plaster molds, Other Engineering

Assignment Help:

           Plastic molds are made of plaster of Paris (gypsum) or calcium sulphate, talc and silica flour is added in the plaster of Paris to improve strength and to control the time required for the plaster to set. These ingredients are mixed with water and the resulting slurry is poured over the pattern.

           The plaster sets within 15 minutes usually. After the plaster sets, the pattern is removed and the mould is dried at 120°C -260°C to remove the moisture. The mould halves are assembled to form the mould cavity and are preheated to about 120°C. The molten metal is then poured into the mould.

           Patterns for plaster moulding are generally made of Aluminum, thermosetting plastics, brass or zinc alloys. Wood patterns are not appropriate for producing a large number of mould because they are repeatedly in contact with the water based plaster slurry.


Related Discussions:- Plaster molds

Industrial buildings inspections-fire protection engineering, Industrial Bu...

Industrial Buildings Inspections: Fire safety within industrial buildings falls largely within the scope of more general precautions and recommendations given in Chapter of NF

Vlsi, Working of bi- CMOS invertor in vlsi

Working of bi- CMOS invertor in vlsi

Aerodynamics-flow model diagram , We will need to use several different flo...

We will need to use several different flow models as we go along. It is crucial to understand the simplifications used to obtain these models because these limit the validity of th

Bjt, why we use h for bjt

why we use h for bjt

Financial managment, what is the consideration of time importance in financ...

what is the consideration of time importance in financial management? how can time time be adjust illustrate you?

Fresnel''s and fraunhofer''s classes of diffraction, Q. Distinguish between...

Q. Distinguish between Fresnel's and Fraunhofer's classes of diffraction. Show that the relative intensities of successive maxima of Fraunhofer diffraction at single slit are

Power factor., how can decrease the power factor of any electric circuit

how can decrease the power factor of any electric circuit

Components of amplifier, Expertsmind.com brings you unique solution in el...

Expertsmind.com brings you unique solution in electrical engineering RESISTORS: Resistors are designed to drop the amount of voltage going through them, this allow

Avionic systems design- stability derivatives, The idea of stability deriva...

The idea of stability derivatives is to approximate the general functional relationship between any force ormoment variable and the dynamic or control variables as a Taylor series

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd