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SILISIL RTV MF-Dura 40

SILISIL RTV MF-Dura 40

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SILISIL RTV MF-Dura 40 — 2K addition silicone Shore A 40 — higher hardness for durable industrial molds, available from Swiss stock.

2K addition silicone Shore A 40 (blue, mixing ratio 1:1) — higher hardness for durable industrial molds.

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  • brand
  • Mixing ratio
  • Networking type
  • Paint has hardened
  • Self-leveling
  • Density (g/cm³)
  • Viscosity uncrosslinked (mPa·s)
  • Electrical insulation
  • Potting time (min)
  • Demolding time (min)
  • Full networking (h)
  • Food contact
  • Suitable for medical use
  • Certificates
  • Shore hardness A (cured)
  • Elongation at break (%)
  • Container

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Mold making SILISIL silicone RTV-2 Swiss bearing addition Platinum Shore A 40 Prototyping Swiss brand 2K Moulding / Mold making

 
General Terms and Conditions.

Shipping usually within 1 to 3 business days
(availability will be confirmed after ordering)

. Express logistics. Fast and reliable within Switzerland & Europe.

Shipping from Swiss warehouse within 24 hours. Batch certificate. Invoice within 30 days (B2B). Technical support.
Shipping & Delivery

Usually 1 to 3 working days

Availability will be confirmed after order receipt.

Express logistics within Switzerland & Europe.

General Terms and Conditions →

Product data

HS code: 3910.0000

HS code: 3910.0000

SILISIL RTV MF-Dura 40
SILISIL RTV MF-Dura 40
SILISIL ·

SILISIL RTV MF-Dura 40 is a room temperature vulcanizing 2-component addition silicone (platinum crosslinking, RTV-2) of the MF-Mold & Form series — 2K addition silicone Shore A 40 — higher hardness for heavy-duty industrial molds.

The mixture is prepared in a 1:1 ratio by weight (tolerance ±5%). Pot life at 23°C is approximately 50 minutes, demolding is possible after approximately 4 hours, and complete curing takes 24 hours. Temperature resistant from -40°C to +200°C.

Key feature

Higher final hardness (Shore A 40) — the right choice for robust industrial molds that must withstand mechanical stress without deformation.

SILISIL RTV MF-Dura 40 in figures
A 40
Shore hardness
5'500
mPa·s viscosity
50 min
Pot life @23 °C
250 %
Elongation at break

What distinguishes SILISIL RTV MF-Dura 40

Higher hardness Shore A 40
Higher final hardness for mechanically stressed molds with good service life.
Low viscosity 5,500 mPa·s
Low mixing viscosity — flows into the finest structures without air inclusions, vacuum venting optional.
Tear resistance 15 N/mm
High tear resistance — robust against mechanical stress when demolding abrasive materials.
Mixing ratio 1:1 by weight
Simple 1:1 ratio — mixable by hand without precision scales, ideal for workshops and hobbyists.
Shrinking arm
Shrinkage during addition crosslinking — shape is immediately dimensionally stable without waiting time.
Temperature resistant from -40 to +200 °C
Expanded range of applications for hot wax applications and mold storage in extreme climates.

What is SILISIL RTV MF-Dura 40 used for?

Industrial tool molds
Shore A 40 for mechanically stressed molds — suitable for serial molding with polyester, epoxy and PU resins.
Concrete and manufactured stone series forms
Higher final hardness extends the mold lifespan when casting abrasive concrete mixtures — paving stones, columns, and stone facades.
Master models for injection molds
Dimensionally stable reproduction of tool master models for subsequent machining in toolmaking.
Mold making for low-melting alloys
Temperature resistant up to +200 °C — suitable for Sn-Bi solders, Wood's Metal and similar model-making alloys with a melting point well below 200 °C.
High-volume jewelry wax molds
High final hardness allows more wax castings per mold without loss of detail — economical for series production.
Robust shapes for DIY and craft applications
Durable molds for restoration, model making and artist supplies — elongation at break 250% at Shore A 40.

processing

1
Prepare the original
The surface to be reproduced must be clean, dry, and dust-free. The ideal processing temperature is 23°C — cooler environments significantly extend the pot life and curing time.
2
homogenize and mix components
Stir the base and catalyst thoroughly before use. Weigh out 1:1 by weight (tolerance ±5%). When mixing, thoroughly incorporate the mixture into the container walls and bottom.
3
Vacuum venting
For non-porous molds, briefly de-aerate the mixture under vacuum — trapped air bubbles are removed and a smooth mold surface is guaranteed.
4
Pour slowly into the mold
Pour in a thin stream from a height of approximately 30 cm into the lowest point — the silicone displaces air on its own and reaches all undercuts.
5
Vulcanizing and demolding
At 23 °C, demolding is possible after approximately 4 hours, with complete curing after 24 hours. A 24-hour "maturation phase" is required before the first casting to ensure maximum strength.
Data sheets & safety data sheet
Full TDS and SDS in DE, EN, FR — view or download directly.
To the documents →

Important instructions

Avoid crosslinking inhibitors
Additive systems like MF-Dura 40 are sensitive to sulfur, amine, tin, and phosphorus compounds—especially latex gloves, modeling clay, adhesive tapes, and some paints. If in doubt, make a small test cast before use.
Storage and shelf life
In its unopened original container, the product has a shelf life of at least 12 months when stored in a dry, cool place (10–25 °C). Consult the Safety Data Sheet (SDS) before opening.
Available packaging
1 kg + 1 kg, 5 kg + 5 kg, 25 kg + 25 kg, 200 kg + 200 kg. Other container sizes available on request.
compatibility
Compatible with polyurethane, epoxy, and polyester casting resins. Apply a release agent to protect the mold when using aggressive resins.

Recommended accessories

SILISIL Vaseline release paste white
Universal release agent for polyester, epoxy and polyurethane casts — protects the silicone mold from aggressive resins and extends the mold's lifespan.
View product →
SILISIL Delayer PA
Retarder for addition silicones — extends pot life and setting time for more complex multi-part structures and relaxed processing.
View product →
SILISIL Silicone Remover
Cleaning agent for silicone residues on tools, models and work surfaces — gentle and effective.
View product →

Which MF silicone for which application?

SILISIL RTV MF-Dura 40 in direct comparison with related MF products in our range (MF = Mold & Form).

MF-Dura 40
Current product 		MF-Dura 30 →MF-Dura 32 →MF-Dura 35 →
Shore hardness A40?3233
Mixed viscosity5'500?6'0007'500
ColorBlue?reddish-brownTranslucent
Pot life @23 °C50?1020
Topics & Application Areas
Key terms related to this product. Also useful for our search and filters.
Mold making SILISIL silicone RTV-2 Swiss bearing addition Platinum Shore A 40 Prototyping Swiss brand 2K Moulding / Mold making

Technical data for SILISIL RTV MF-Dura 40

All 17 product information 4 Physical properties 4 Electrical properties 1 Curing values ​​3 Product approvals 3 Mechanical properties 2
Product information
brand SILISIL
Mixing ratio 1:1
Networking type Addition (Platinum)
Container 1kg + 1kg, 5kg + 5kg, 10kg + 10kg, 25kg + 25kg
Physical properties
Paint has hardened Blue
Self-leveling Yes
Density (g/cm³) 1.12
Viscosity uncrosslinked (mPa·s) 5500
Electrical properties
Electrical insulation Yes
Curing values
Potting time (min) 50
Demolding time (min) 4
Full networking (h) 24
Product approvals
Food contact No
Suitable for medical use No
Certificates RoHS, REACH
Mechanical properties
Shore hardness A (cured) A 40
Elongation at break (%) 250

For binding values, please refer to the technical data sheet (TDS) in the "Documents" tab.

Documents and datasheets

Click on a document for a preview or the download icon for a direct download.

Technical Data Sheets (TDS) 3
SILISIL RTV MF-Dura 40 - Technical Data Sheet DE.pdf
124 KB
SILISIL RTV MF-Dura 40 - Technical Data Sheet EN.pdf
123 KB
SILISIL RTV MF-Dura 40 - Fiche Technique FR.pdf
123 KB

Frequently asked questions about SILISIL RTV MF-Dura 40

Practical application and design questions — answered by SILITECH.

SILISIL RTV MF-Dura 40 is a two-component (Shore A 40, blue) addition silicone for industrial tool molds and related applications. Two-component addition silicone Shore A 40 — higher hardness for durable industrial molds

At 23 °C, the pot life is approximately 50 minutes and the demolding time approximately 4 hours. Complete curing is achieved after 24 hours. Lower temperatures extend, higher temperatures shorten these times.

As an addition system, SILISIL RTV MF-Dura 40 is sensitive to crosslinking inhibitors: sulfur, amine, tin, and phosphorus compounds can locally halt vulcanization. Avoid latex gloves, sulfur-containing modeling clays, some adhesive tapes, and PVC plasticizers in the immediate vicinity of the mold. If in doubt, make a small test cast.

SILISIL RTV MF-Dura 40 is mixed in a 1:1 ratio by weight (base to catalyst), with a maximum tolerance of ±5%. Homogenize both components separately before mixing, then thoroughly incorporate them – including the container walls and bottom. Brief vacuum degassing of the mixture is recommended for non-porous molds.

SILISIL RTV MF-Dura 40 achieves a Shore A hardness of 40 (ASTM D 2240), a tensile strength of >4.0 N/mm² (ASTM D 412), an elongation at break of approximately 250% and a tensile strength of 15 N/mm (ASTM D 624).

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Product specifications

Product information
Container 1kg + 1kg or 5kg + 5kg or 10kg + 10kg or 25kg + 25kg
brand SILISIL
Mixing ratio 1:1
Networking type Addition (Platinum)
Physical properties
Paint has hardened Blue
Self-leveling Yes
Density (g/cm³) 1.12
Viscosity uncrosslinked (mPa·s) 5500
Electrical properties
Electrical insulation Yes
Curing values
Potting time (min) 50
Demolding time (min) 4
Full networking (h) 24
Product approvals
Certificates RoHS or REACH
Food contact No
Suitable for medical use No
Mechanical properties
Shore hardness A (cured) A 40
Elongation at break (%) 250
Keywords
Keywords
Mold making SILISIL silicone RTV-2 Swiss bearing addition Platinum Shore A 40 Prototyping Swiss brand 2K Moulding / Mold making

Documents and datasheets

Safety Data Sheets (SDS) and Technical Data Sheets (TDS) are available for download: