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

Turbine discs and blades of aircraft, Turbine Discs and Blades: The ins...

Turbine Discs and Blades: The inspection for cracks is of the utmost importance, most inspections are visual, the dye penetrant method of inspection being too impractical. Crac

Logic gate - not gate, THE INVERTER ('NOT' GATE) Figure shows the symbo...

THE INVERTER ('NOT' GATE) Figure shows the symbol for an inverter, where the output will produce the complement of the input. This device is often employed when the complement

Physical chemistry, can you answer some problem from physical chemistry wit...

can you answer some problem from physical chemistry with a detailed approach why and how one should choose the steps in solving them.These are just random question that I have no c

Equivalent shaft horsepower - aircraft maintenance , Equivalent Shaft Horse...

Equivalent Shaft Horsepower (EHP) In practice there is always a certain amount of jet thrust in the total output of the turbo-propeller engine and this must be added to the s.h

Heat transfer, Q. 1 A 50 cm diameter pipeline in the Arctic Carries hot oi...

Q. 1 A 50 cm diameter pipeline in the Arctic Carries hot oil at 30 0C and exposed to a coefficient surrounding temperature of -20 0C. Special powder insulation 5 cm thick surround

Construction, What are the problems arises during construction and their so...

What are the problems arises during construction and their solutions

Means of escape from trains - railway inspections, Means of escape from tra...

Means of escape from trains - railway inspections: The means of  escape from  trains is also considered  in  NFPA130.     Some  of  the considerations are: At least two eme

Explain the concept of postmodernism in detail, Question 1 Write a long no...

Question 1 Write a long note on Professional Cultures in a ‘Golden Age' Question 2 Write a long note on the Global and Local Interrelationship Question 3 Write a long no

Means of escape - place of safety, Means of escape - place of safety: ...

Means of escape - place of safety: The means of escape in a building are often supplemented by a fire warning system that may or may not include automatic detection, depending

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