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

How do comets get their tails, How do comets get their tails? - Most comet...

How do comets get their tails? - Most comets stay frozen in the outer solar system. Only a few enter the inner solar system where they can grow tails. - When a comet nears the sun

Water, Dear Sir, Please answer the follwing question . Specs: Filterati...

Dear Sir, Please answer the follwing question . Specs: Filteration Capacity 18000 LPH , Tested pressure 6Kg/Sq.cm, Vertical MS pressure Sand filter(flat ends 6mm thick & di

Leverage, defination of leverage,objectives,enterpritation,analysis,conclus...

defination of leverage,objectives,enterpritation,analysis,conclusion,references,review of literature.

Junction diode summary, The PN junction region of the Junction Diode has ...

The PN junction region of the Junction Diode has the following significant characteristics: Semiconductors contain two types of mobile charge carriers, Electrons and Holes

Servicing of chemical de-icing systems, SERVICING OF CHEMICAL DE-ICING SYST...

SERVICING OF CHEMICAL DE-ICING SYSTEMS: It is essential for the correct operation of the ice protection system that servicing is carried out on a regular basis.  The fluids use

Thermodynamics of materials, outline five (5) areas where thermodynamics ca...

outline five (5) areas where thermodynamics can be applied in materials engineering

Engine torque, ENGINE TORQUE It is the force of rotating action about t...

ENGINE TORQUE It is the force of rotating action about the crankshaft axis at any given instant of time. It is given by,

Tubular joint fatigue, tubular joint root fatigue criteria and creteria abo...

tubular joint root fatigue criteria and creteria about tubular joint fatigue for inersid weld toe welded from both side

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