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

Vibration analysis of aircraft, Vibration Analysis Gas turbine engines ...

Vibration Analysis Gas turbine engines have extremely low levels of vibration compared to piston engines. Changes in vibration levels could occur therefore without being notic

Germanium, why germanium become intrinsic at high temperature

why germanium become intrinsic at high temperature

Finance, Derive the functional relationship between the no-arbitrage values...

Derive the functional relationship between the no-arbitrage values of the two vertical spreads.

Electronics., Limitations of shunt clippers

Limitations of shunt clippers

Variables and quantifiers in first-order logic, Variables and Quantifiers i...

Variables and Quantifiers in First-Order Logic - Artificial intelligence: Now suppose that we wanted to say that there is a meal at the Red Lion which costs only three pounds.

The world of fiance, Answer the following questions: What are the three for...

Answer the following questions: What are the three forms of a business organization? What are the advantages and disadvantages of each form? For a corporation, what is the overall

Masonry dams with trapezoidal cross section, How to calculate the depth of ...

How to calculate the depth of a masonry dam of trapezoidal cross section with height of 24ft,2ft top width,,12 ft base width and weight of concrete 150 lb/ft^3.The resultant pressu

Thermodynamics, original temp. of plate is 25 degree c.when put in burnace ...

original temp. of plate is 25 degree c.when put in burnace its upper part is 250 c and lower is 100 and mass is 56kg.find out heat transfer

MICROPROCESSOR, The access time of ROM using bipolar transistors is about

The access time of ROM using bipolar transistors is about

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