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

Angle rate systems , Traditionally, seekers have been simple correlation tr...

Traditionally, seekers have been simple correlation trackers and a set of gimbals that are used to measure the angle rates of the target.          - Infrared seekers detect a

Climbing drum peel test , Climbing Drum Peel Test The CDP test works by a...

Climbing Drum Peel Test The CDP test works by attaching a free end of a face sheet of a sandwich panel to a drum which then rolls across the panel, peeling off the face sheet. A

New building completion - fire safety management, Ne w building completion...

Ne w building completion: New buildings have to be constructed to meet certain fire safety standards.  It is not acceptable for buildings to be built that do not attain a min

Fire alarm systems, Fire alarm systems: All buildings require a means ...

Fire alarm systems: All buildings require a means by which the warning  of  fire  can  be  given  to  all occupants.  In the very smallest premises this might be achievable by

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

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

Matlab, program how to estimate the inner curve using spline interpolation

program how to estimate the inner curve using spline interpolation

Market value, Calculate the market value of a firm with total assests of $1...

Calculate the market value of a firm with total assests of $105 million and $50 million of 10% perpetual debt in the capital structure. The firm''s cost of equity is 14% on the $55

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