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SILISIL RTV MF-PuttyFast 38

SILISIL RTV MF-PuttyFast 38

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SILISIL RTV MF-PuttyFast 38 — 2K putty Shore A 38 — fast reproduction without mold tooling, available from Swiss stock.

2K addition silicone Shore A 38 (light violet, mixing ratio 1:1) — fast reproduction without mold tooling.

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  • Networking type
  • Container
  • Paint has hardened
  • Self-leveling
  • Density (g/cm³)
  • Electrical insulation
  • Demolding time (min)
  • Full networking (h)
  • Food contact
  • Suitable for medical use
  • Certificates
  • Shore hardness A (cured)
  • Tensile strength (MPa)
  • Elongation at break (%)
  • Tensile strength (N/mm)

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Mold making SILISIL silicone RTV-2 Swiss bearing additive Platinum prototyping Swiss brand 2K Moulding / Mold making Fast Putty / Kneadable Shore A 38

 
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
SILISIL RTV MF-PuttyFast 38
SILISIL RTV MF-PuttyFast 38
SILISIL ·

SILISIL RTV MF-PuttyFast 38 is a room temperature vulcanizing 2-component addition silicone (platinum crosslinking, RTV-2) of the MF-Mold & Form series — 2K putty Shore A 38 — fast reproduction without mold tooling.

The mixture is prepared in a 1:1 ratio by weight (tolerance ±5%). Pot life at 23°C is approximately 3 minutes, demolding after approximately 12 minutes, and complete curing after 24 hours. Temperature resistant from -40°C to +200°C.

Key feature

2-component modeling clay for the fastest mold production: Knead base and catalyst (1:1) between your hands and press directly onto the model — mold ready in 12 minutes.

SILISIL RTV MF-PuttyFast 38 in figures
A 38
Shore hardness
modeling clay
consistency
3 min
Pot life @23 °C
200 %
Elongation at break

What distinguishes SILISIL RTV MF-PuttyFast 38

Modeling clay — no container needed
Direct hand processing without container, mixer or vacuum chamber — the fastest way to the shape.
Potting time 3 minutes
Very short processing time — suitable for high-throughput production with short mold cycles.
Setting time 12 minutes
Controlled setting time — reliable planning of the mold cycle.
Heat resistant for low-temperature metals
Suitable for direct casting of low-melting alloys — Wood's Metal, Sn-Bi solders, <200 °C.
Mixing ratio 1:1
Simple 1:1 ratio — mixable by hand without precision scales, ideal for workshops and hobbyists.
Simple processing by hand
Direct hand processing — no mixing machine, no vacuum, no special tools required.

What is SILISIL RTV MF-PuttyFast 38 used for?

Instant molds without tools
Mix the modeling clay between your hands and press it directly onto the model — creating shapes where no container is possible or desired.
Repair and model correction
Putty fills cracks, damage and missing areas — vulcanizes to Shore A 38 in 12 minutes.
Low-melt alloy castings
Temperature resistant up to +200 °C — suitable for Sn-Bi solders, Wood's Metal and model maker alloys with a melting point well below 200 °C, without preform.
Fast, detailed molding in jewelry
A potting time of 3 minutes is sufficient to create a putty mold directly on a piece of jewelry — ready for wax casting in 15 minutes.
Mobile on-site impressions
Perfect for everyday restoration and museum use — putty ready to use without mixer, vacuum or container.
Maker and hobby prototyping
Easiest 1:1 processing by hand — perfect for training, maker spaces and DIY projects.

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 12 minutes; complete curing takes 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-PuttyFast 38 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 casting 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. 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-PuttyFast 38 in direct comparison with related MF products in our range (MF = Mold & Form).

MF-PuttyFast 38
Current product 		MF-Spray 25-6 →MF-Dura 35 Fast →MF-Dura 30 →
Shore hardness A382535?
Mixed viscosity(Play-Doh)8'0007'500?
ColorLight purpleLight blueGreen?
Pot life @23 °C361?
Topics & Application Areas
Key terms related to this product. Also useful for our search and filters.
Mold making SILISIL silicone RTV-2 Swiss bearing additive Platinum prototyping Swiss brand 2K Moulding / Mold making Fast Putty / Kneadable Shore A 38

Technical data for SILISIL RTV MF-PuttyFast 38

All 15 product information 2 Physical properties 3 Electrical properties 1 Curing values ​​2 Product approvals 3 Mechanical properties 4
Product information
Networking type Addition (Platinum)
Container 500g+500g, 1kg+1kg, 25kg+25kg
Physical properties
Paint has hardened Light purple
Self-leveling Thixotropic
Density (g/cm³) 1.42
Electrical properties
Electrical insulation Yes
Curing values
Demolding time (min) 12
Full networking (h) 24
Product approvals
Food contact No
Suitable for medical use No
Certificates RoHS, REACH
Mechanical properties
Shore hardness A (cured) A 38
Tensile strength (MPa) 1.3
Elongation at break (%) 200
Tensile strength (N/mm) 4

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-PuttyFast 38 - Technical Data Sheet DE.pdf
149 KB
SILISIL RTV MF-PuttyFast 38 - Technical Data Sheet EN.pdf
152 KB
SILISIL RTV MF-PuttyFast 38 - Technical Data Sheet FR.pdf
155 KB

Frequently asked questions about SILISIL RTV MF-PuttyFast 38

Practical application and design questions — answered by SILITECH.

SILISIL RTV MF-PuttyFast 38 is a two-component (Shore A 38, light purple) additive silicone for instant molding without tooling and related applications. Two-component putty Shore A 38 — fast reproduction without molding tools

At 23 °C, the pot life is approximately 3 minutes and the demolding time approximately 12 minutes. Complete curing is achieved after 24 hours. Lower temperatures extend, higher temperatures shorten these times.

As an addition system, SILISIL RTV MF-PuttyFast 38 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 casting.

SILISIL RTV MF-PuttyFast 38 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-PuttyFast 38 achieves a Shore A hardness of 38 (ASTM D 2240), a tensile strength of 1.3 N/mm² (ASTM D 412), an elongation at break of approximately 200% and a tear resistance of 4 N/mm (ASTM D 624).

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Product specifications

Product information
Container 500g + 500g or 1kg + 1kg or 25kg + 25kg
Networking type Addition (Platinum)
Physical properties
Paint has hardened Light purple
Self-leveling Thixotropic
Density (g/cm³) 1.42
Electrical properties
Electrical insulation Yes
Curing values
Demolding time (min) 12
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 38
Tensile strength (MPa) 1.3
Elongation at break (%) 200
Tensile strength (N/mm) 4
Keywords
Keywords
Mold making SILISIL silicone RTV-2 Swiss bearing additive Platinum prototyping Swiss brand 2K Moulding / Mold making Fast Putty / Kneadable Shore A 38

Documents and datasheets

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