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

Identify the key issues evident at global mining, The atmosphere in the roo...

The atmosphere in the room was tense. Ted Kimoski, Financial Director for Global Mining, had justfinished his presentation. John Campbell, Managing Director, sat quietly making not

Case law on evaluatig credit requests, This case has been framed in order t...

This case has been framed in order to test the skills in evaluating a credit request and reaching a correct decision. Perluence International is large manufacturer of petroleum and

Defects are likely to result in castings, Q. What kind of defects are likel...

Q. What kind of defects are likely to result in castings due to the following?         (i) Core prints on the core are undersigned.        (ii) Core prints on the core

Methods of strengthen crystalline materials against plastic , Q. Describe t...

Q. Describe the four main methods of strengthen crystalline materials against plastic yield. Ans. (1) Work Hardening: Strain hardening or work hardening is a phenomenon which

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

What are the problems arises during construction and their solutions

Dsp, h(t) is an analog IIR filter, with the poles lambda_1 = -1, lambda_2 =...

h(t) is an analog IIR filter, with the poles lambda_1 = -1, lambda_2 = -1+i, lambda_3 = -1-i and no zeros. let h[n] be a digital IIR filter with poles which defined by e^lambda_i a

Fire safety management for commercial buildings, fire safety management for...

fire safety management for Commercial buildings: Commercial buildings where all the occupants are familiar with the building we also need to see evidence of satisfactory fire

Public health eng, Design a sewer collection system incorporating flow rate...

Design a sewer collection system incorporating flow rates, pipe sizes and pipe slopes for the proposed residential development shown in the attached drawing. In your design, locat

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