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

Blow moulding and thermoforming process, Q . Write short note on blow moldi...

Q . Write short note on blow molding. OR Explain the Thermoforming process.   What are the plastic fabrication method write in brief with neat sk

Identify fire hazards - fire risk assessment , Identify fire hazards: ...

Identify fire hazards: In this part, the process appears to be concentrating on issues that can lead to fire but we have to remember to also consider the presence of a fire wi

Permeability of moulding sand, Permeability of Moulding Sand  is the proper...

Permeability of Moulding Sand  is the property of the sand, which permits the gases and steam to escape through the sand mould. For this purpose, the sand must be porous. Permeabil

Aircraft maintance, Explain different types of intakes of aircraft

Explain different types of intakes of aircraft

Casting methods, Special Casting Methods             1. Die casting : ...

Special Casting Methods             1. Die casting : Die casting is a permanent mould casting techniques in which molten metal is forced in the mould cavity under a pressure

Engine speed indicators, Engine speed indicators: All engines have thei...

Engine speed indicators: All engines have their rotational speed (R.P.M.) indicated. On a twin or triple-spool engine, the high pressure assembly speed is always indicated; in

Protected escape routes - means of escape, Protected escape routes - fire p...

Protected escape routes - fire protection engineering: Protected escape routes: Does the fire resistance fully enclose the protected routes? Do the fire doors

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

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