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

Frequency warping, main difference between warping and without warping

main difference between warping and without warping

AERONAUTIC PROJECT, hello sir, i am a FINAL YEAR B.E STUDENT...NOW i am in ...

hello sir, i am a FINAL YEAR B.E STUDENT...NOW i am in the stage of doing a PROJECT...please give me some ideas in the field of AERODYNAMICS for doing PROJECT..

Finance question, Say that a buyer of bonds values good bonds at $500 and v...

Say that a buyer of bonds values good bonds at $500 and values bad bonds at $250. Sellers of both good and bad bonds value them at $350. If the fraction of good sellers and bad s

Mine engineering, Students are to undertake a tunnel blast design for the f...

Students are to undertake a tunnel blast design for the following conditions: • Tunnel is 5.5m wide by 5.5.m high • Rock is a sandstone with a UCS of 400 MPa • Drill hole diameter

Fire suppression in aircraft , Fire suppression Typical fixed systems i...

Fire suppression Typical fixed systems in the types of aircraft for which fixed fire extinguisher systems are specified, it is usual for the extinguishant to be stored in the c

Budget and determining, In Corporate finance, Experts engaged in this occup...

In Corporate finance, Experts engaged in this occupation have the liability to increase the organization's revenue, shareholder's money, investment spending budget and determining

Divided entrance duct - aircraft engine, Divided entrance duct On a sin...

Divided entrance duct On a single engine aircraft with fuselage mounted engines, either a wing root inlet or a side scoop inlet may be used. The wing root inlet presents a pro

Fuel control system in aircraft engine, Fuel control system in Aircraft Eng...

Fuel control system in Aircraft Engine: The computer controls the fuel flow to the engine to maintain a constant rotor RPM. During normal operation the optimum engine/rotor spe

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