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

Paint, What are the ingredients of paint. Explain?

What are the ingredients of paint. Explain?

Trusses, Analysis of truste,2D truss analysis using method of joint(cantile...

Analysis of truste,2D truss analysis using method of joint(cantilever & simply support)?

Pitch lock mechanism, PITCH LOCK MECHANISM The pitch lock mechanism is ...

PITCH LOCK MECHANISM The pitch lock mechanism is necessary to cater for the two fine pitch position of 'flight fine pitch' and 'ground fine pitch'. It acts as a safety device

Transistor configurations, TRANSISTOR CONFIGURATIONS: Before a transist...

TRANSISTOR CONFIGURATIONS: Before a transistor can be used, it must be connected into an input circuit (by two wires) and an output circuit (two wires).  However, because the t

Important techniques for compacting of metal powders, Q.6 Define powder-met...

Q.6 Define powder-metallurgy. What are various important techniques for compacting of metal powders ? Ans. Powder metallurgy is a technique of producing metal powders and mak

Evacuation of a high rise building - means of escape, Evacuation of a high ...

Evacuation of a high rise building - means of escape: Evacuation of a high rise building is likely to be split into two or more phases.  Initially, when the alarm activates (f

Electrical engineering, how to get guidance of projects in electrical engin...

how to get guidance of projects in electrical engineering?

Fire evacuation signals, Fi r e evacuation signals: Members of the ...

Fi r e evacuation signals: Members of the public are known not to respond positively to fire evacuation signals. People will often try to ignore the signal and will try to

Fire prevention - fire risk assessment, Fire prevention - fire risk assessm...

Fire prevention - fire risk assessment: Fire prevention measures include: Reducing the combustible materials, Reducing the risk of ignition, Reducing

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