This document provides information about RTV silicone mould making. It begins with basic terms related to casting and mould making. It then discusses RTV silicone, explaining that there are two types: RTV-1, which hardens due to atmospheric humidity, and RTV-2, which is a two-component system that cures at room temperature when the components are mixed. The document outlines the steps to make an open silicone mould and a two-part silicone mould. It notes advantages like excellent release properties and high temperature resistance, and disadvantages like expense and viscosity. It concludes by referencing additional sources for more information.

1. RTV silcone mould

2. Presnted by…………………………..
shubham maurya
(18MECH16)
CNTRE FOR ADVANCED STUDIES
A.K.T.U
LUCKNOW,UP

3. Contents
Introduction
basic terms
RTV Silicone
RTV-1
RTV-2
Steps used in RTV SILICONE mould making
Advantages
Disadvantages
Application
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4. Intoduction
◈
Silicone rubber is an excellent moulding material used mainly where minute
surface detail is required usually in conjunction with deep undercuts. There
is virtually no shrinkage and is recommended where a larger number of casts
are required.
◈ As there are many types of silicone rubber available this information has
been designed to give a general introduction to its use.
◈ Details such as cure time and percentage of curing agent to add will be stated
on the containers.
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5. Basics terms
What is casting ?
Casting is a manufacturing process in
which a liquid material is usually poured
into a mold, which contains a hollow
cavity of the desired shape, and then
allowed to solidify. ... Casting is most
often used for making complex shapes
that would be otherwise difficult or
uneconomical to make by other methods.
What is mould ?
Mold making is a vital process in which
a material is used for making themold of
the original model. Different materials
can be used for mold making process
depending on each one's needs and
preference. The common material used
for mold making process is the rubber.
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6. Basics……….
What is pattern making ?
In casting, a pattern is a replica of
the object to be cast, used to
prepare the cavity into which
molten material will be poured
during the casting process .
Patterns used in sand casting may
be made of wood, metal, plastics or
other materials
◈ Pattern
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7. RTV SILICONE
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RTV silicone is a liquid silicone compound that cures at room
temperature to form a flexible rubber. This can be either an Adhesive
Sealant, Moulding Rubber or Electronic Encapsulate Potting
Compound.
The term RTV is means Room Temperature Vulcanising.
Room-temperature vulcanizing (RTV) silicone =reactive oil-based
polymers + strengthening mineral fillers
There are two types of room-temperature vulcanizing silicone…

8. RTV-1 (ONE COMPONENT SYSTEM) RTV-2 (TWO COMPONENT SYSTEM)
Hardens due to the action of
atmospheric humidity, a catalyst,
and acetoxysilane .
Acetoxysilane+Humidity=acetic.
The curing process begins on the
outer surface and progresses
through to its core.
The product is packed in airtight
cartridges and is either in a fluid or
paste form. RTV-1 silicone has
good adhesion, elasticity, and
durability characteristics.
◈ Two-component products that,
when mixed, cure at room
temperature to a solid
elastomer, a gel, or a flexible
foam.
◈ RTV-2 remains flexible from
−80 to 250 °C (−112 to
482 °F).
◈ Break-down occurs at
temperatures above 350 °C
(662 °F), leaving an inert silica
deposit that is non-flammable
and non-combustible
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9. RTV-2
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◈ RTV-2 is used to make flexible moulds, as well as many technical parts
for industry and paramedical applications.
◈ They can be used for electrical insulation due to their dielectric
properties.

10. Steps used in RTV SILICONE mould making
◈ SIMPLE OPEN MOULD
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11. Steps used in RTV SILICONE mould making
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13. CARES TO BE TAKEN
◈ the mould box should then be
coated with a fine layer of
petroleum jelly.
◈ Allow to stand for
approximately 10 minutes
before pouring the bulk, hold
the container as low as possible
and pour in a thin stream.
◈ Mix the silicone rubber and if a
vacuum is not available paint
over the surface of the master
pattern with a thin coat.
◈ Leave to cure for 24 hours
before removing the mould.
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14. Two Part Mould
◈ A part mould (split mould) is necessary where it is difficult to remove either
the master or the castings from an open mould.
◈ STEPS…..
◈ Pattern to be to be made with help of rapid prototyping system techniques.
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15. Two Part Mould
◈
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17. Advantages and
◈ RTV silicone rubber has
excellent release properties
compared to molds rubbers,
which is especially an
advantage when doing
production casting of resins
(polyurethane, polyester,
and epoxy).
◈ No release agent is required,
obviating post-production clean
up.
◈ Silicones also exhibit good
chemical resistance and high-
temperature resistance (205 °C,
400 °F and higher).
◈ For this reason, silicone molds
are suitable for casting low-
melt metals and alloys
(e.g. zinc, tin, pewter,
and Wood's metal)
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18. Disadvantages
◈ RTV silicone rubbers are,
however, generally
expensive—especially
platinum-cure.
◈ They are also sensitive to
substances (sulfur-
containing modelling clay such
as Plastilina ) that may prevent
the silicone from curing .
◈ Silicones are usually very thick
(high viscosity), and must be
vacuum degassed prior to
pouring, to minimize bubble
entrapment.
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19. References
◈ Jorge Cervantes, Ramón Zárraga, Carmen Salazar-Hernández "Organotin
catalysts in organosilicon chemistry" Appl. Organometal. Chem. 2012,
vol. 26, 157–163. doi:10.1002/aoc.2832
◈ ^ Jump up to:a b Hans-Heinrich Moretto, Manfred Schulze, Gebhard
Wagner (2005) "Silicones" in Ullmann's Encyclopedia of Industrial
Chemistry, Wiley-VCH, Weinheim. doi:10.1002/14356007.a24_057
◈ ^ "picsima-ii". picsima-ii. Retrieved 2017-01-05.
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20. THANK YOU
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