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

Engineering signals, Engineering Signals A signal is a variation of a m...

Engineering Signals A signal is a variation of a measurable quantity that conveys information about the behaviour of a system. • A signal can depend upon a single variable o

Excel, How do I finish a tough Engineering assignment in excel?

How do I finish a tough Engineering assignment in excel?

Time value money, I want to buy a car. The Msrp is $31,000. I pay $516 per ...

I want to buy a car. The Msrp is $31,000. I pay $516 per month for five years. The quoted apr is 6.9%. I put down $800. How much did I pay for the car?

Pn junction diode, what is the effect of temperature on pn junction diode o...

what is the effect of temperature on pn junction diode of component

Control engineering, what are the components, applications, benefits and dr...

what are the components, applications, benefits and drawbacks of control engineering?????

Aviation legislation design and type certificate, Design, Construction and ...

Design, Construction and Type Certificate The following chapter covers the initial design, construction, registration and test flying of the first prototype of a new aircraft.

Heat transfer, #questionA piece of Al weighing 6 kg and initially at a temp...

#questionA piece of Al weighing 6 kg and initially at a temperature of 300OC is suddenly immersed in a fluid at a temperature of 20OC. The convectice heat transfer coefficient is 5

Final project, can u give idea about project in agriculture

can u give idea about project in agriculture

Fire safety management for restaurants, Fire safety management for restaura...

Fire safety management for restaurants: Staff in restaurants must be aware that customers who have been served their food are always reluctant to leave that food and evacuate.

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