Skip to content
Website 0 CHF
  1. All products
  2. BLUESIL RTV 3720 B SC (5 kg)
BLUESIL RTV 3720 B SC (5 kg)

BLUESIL RTV 3720 B SC (5 kg)

https://www.silitech.ch/web/image/product.template/3835/image_1920?unique=4957266

Low-viscosity 2K-Pt injection silicone for vacuum bag membranes in composite component construction.

Low-viscosity 2K-Pt sprayable silicone (thixotropic) for vacuum bag membranes in composite component manufacturing (vacuum resin infusion)

CHF 0.00 CHF 0.00 CHF 0.00 Excluding taxes

CHF 0.00 excluding taxes

Price on request

  • brand
  • Manufacturer
  • Networking type
  • Container
  • Number of components
  • consistency
  • Mixing ratio
  • UV resistance
  • Paint has hardened
  • Self-leveling
  • Viscosity uncrosslinked (mPa·s)
  • Electrical insulation
  • Potting time (min)
  • Demolding time (min)
  • Food contact
  • Suitable for medical use
  • Tensile strength (MPa)
  • Elongation at break (%)
  • Tensile strength (N/mm)

This combination does not exist.

Add to cart Request sample
Contact us
Blue silicone BLUESIL thixotropic 2K silicone ELKEM Swiss bearing aviation RTV addition platinum catalyst protective coating boatbuilding 5 kg 1:1 RTV 3720 vacuum bag vacuum pouch composite VARTM infusion slow-cure SC casting application

 
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

Internal reference: 40-2309B.KN.K005

HS code: 39100000

Internal reference: 40-2309B.KN.K005
HS code: 39100000

BLUESIL RTV 3720 B SC (5 kg)
BLUESIL RTV 3720 B SC (5 kg)
Bluesil Elkem Silicones SKU 40-2309B.KN.K005​

Bluesil RTV 3720 A & B is a low-viscosity 2K-Pt sprayable silicone (sprayable, thixotropic) for vacuum bag membranes in composite component construction (vacuum resin infusion).

This product line comprises 2K polyaddition silicone elastomers for composite manufacturing — sprayable, thixotropic, for reusable vacuum bag membranes in vacuum resin infusion. RTV 3720 is tailored to specific industrial applications — the most important properties and areas of application are listed below.

Sprayable with thixotropic behavior

Bluesil RTV 3720 is specifically designed for the production of reusable silicone vacuum bags on composite molds. It features low viscosity for good spraying, is slightly thixotropic for vertical application, and cures quickly (pot life 3 min, demolding 15 min).

RTV 3720 in numbers
Sprayable
thixotropic
Shore A 20
soft
500 %
Elongation at break
15 kN/m
Tear resistance

What makes the RTV 3720 stand out

Specifically for vacuum resin infusion
Reusable silicone vacuum bags on composite tool molds.
Sprayable + thixotropic
Can also be sprayed on vertical surfaces without running off.
Two variants
RTV 3720 A&B (Fast Cure, 3 min pot life) for spraying; RTV 3720 SC A&B (Slow Cure, 25 min) for watering.
High elongation at break (500%)
It survives being attached to and removed from the tool without tearing.
High chemical resistance
Resistant to composite resins (epoxy, polyester).
No toxic emissions
No release of hazardous substances during or after crosslinking.

What is the RTV 3720 used for?

Vacuum resin infusion membranes
Reusable silicone vacuum bags for composite manufacturing.
Composite component tools
Form membranes in carbon/glass fiber processing.
Aerospace composite
Membrane tools in aerospace composite manufacturing.
Marine boatbuilding
Composite boat hulls and decks manufactured using the vacuum process.
Wind turbine rotor blades
Composite components in the wind power industry.
Industrial prototype composite
Quick-change tool membranes for prototypes.
Data sheets & safety data sheet
Full TDS and SDS in DE, EN, FR — view or download directly.
To the documents →

processing

1
Prepare the composite tool
Clean and dry tools; apply a release agent if necessary.
2
Mix A & B
1:1 — Fast Cure (3 min pot life) for spray, Slow Cure (25 min) for casting.
3
spray or pour
Spray the Fast-Cure variant onto vertical tools using a spray gun — thixotropic behavior prevents runoff.
4
Network
15 min (Fast) or 90 min (Slow) at room temperature. Heat accelerates the process — observe dimensional stability.
5
Use vacuum bags
Attach the membrane to the tool, apply a vacuum for resin infusion. Reusable for many cycles.

Recommended accessories

Bluesil Primer PM 820
High-performance primers for polar plastics (PA, PES, ABS, PP) and composites.
View product →
Bluesil Inhibitor 3
Pot life extender for polyaddition silicone systems (Pt-Cure).
View product →

Important instructions

Mixing & Dosage
Stir A and B thoroughly before each use. Use precise dosage in the specified ratio (see table above) — ideally by weight. Incorrect dosage will result in incomplete cross-linking.
Degassing
Degas the mixture under a vacuum of 30–50 mbar. The material expands 3–4 times, then contracts back to its original size after 5–10 minutes. Interrupt the vacuum several times for better degassing.
Avoid inhibitors
Polyaddition silicones are inhibited by: sulfur-vulcanized rubber, tin-catalyzed RTV, amine epoxides, and PVC with tin salts. If in doubt, conduct a preliminary test.
Application advice
SILITECH will advise you on the optimal RTV variant for your application — substrate, hardness, pot life, mechanics. Contact us with your specific application details.

RTV 3720 compared to related RTV products

Networking system, mechanics, and processing times side by side — all values ​​from the official Elkem TDS. “— " = not specified in the datasheet.

RTV 3720
Current product		 RTV 3450 →RTV 3428 →RTV 3440 →
Networking system2K Polyaddition (Pt)2K Polyaddition (Pt)2K Polyaddition (Pt)2K Polyaddition (Pt)
Mixing ratio1 : 110 : 110 : 110 : 1
ColorTranslucent / light blue (B)Beige / black / translucentTransparent / pink / whiteBeige / blue (B)
Shore A hardnessA 20A 50A 28A 40
Elongation at break500 %300 %600 %300 %
Tensile strength4 MPa5 MPa7.5 MPa4 MPa
Tear resistance15 kN/m8 N/mm20 kN/m9 N/mm
Potting time3 min (Fast) / 25 min (SC)90 min1 h90 min
demolding time15 min (Fast) / 90 min (SC)16 h16 h6 h
Mixed viscosity30,000 mPa·s15,000 mPa·s≈25,000 mPa·s15,000 mPa·s
Main applicationVacuum resin infusion membranesHigh-stress tool moldsComplex shapes with undercutsPlaster reproduction
Topics & Application Areas
Key terms related to this product. Also useful for our search and filters.
Blue silicone BLUESIL thixotropic 2K silicone ELKEM Swiss bearing aviation RTV addition platinum catalyst protective coating boatbuilding 5 kg 1:1 RTV 3720 vacuum bag vacuum pouch composite VARTM infusion slow-cure SC casting application

Technical data for BLUESIL RTV 3720 B SC (5 kg)

All 19 product information 7 Further properties 1 Physical properties 3 Electrical properties 1 Curing values ​​2 Product approvals 2 Mechanical properties 3
Product information
brand Bluesil
Manufacturer Elkem Silicones
Networking type Addition (Platinum)
Container 5 kg
Number of components 2K (two-component)
consistency Flowable
Mixing ratio 1:1
Other features
UV resistance No
Physical properties
Paint has hardened Blue
Self-leveling Yes
Viscosity uncrosslinked (mPa·s) 30
Electrical properties
Electrical insulation No
Curing values
Potting time (min) 3
Demolding time (min) 15
Product approvals
Food contact No
Suitable for medical use No
Mechanical properties
Tensile strength (MPa) 4
Elongation at break (%) 500
Tensile strength (N/mm) 15

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

No public documents are available.
We will gladly send you the TDS and SDS by email upon request; please submit a request.

Frequently asked questions about RTV 3720

Practical questions regarding processing and design — answered by SILITECH.

Bluesil RTV 3720 A & B: Low-viscosity, 2-component platinum sprayable silicone (thixotropic) for vacuum bag membranes in composite component manufacturing (vacuum resin infusion). Main applications include vacuum resin infusion membranes, composite component tooling, and aerospace composites.

Polyaddition crosslinking is a two-component silicone chemistry using a platinum catalyst. Component A contains the platinum complex, and component B contains the SiH crosslinker. When mixed, the components crosslink without releasing reaction byproducts—no shrinkage due to outgassing, excellent dimensional accuracy, and low linear shrinkage. Important: Polyaddition silicones are inhibited by various substances—sulfur-vulcanized natural rubbers, tin-catalyzed RTV silicones, amine-catalyzed epoxy resins, and tin-stabilized PVC. In case of doubt, a preliminary test should be carried out.

Thoroughly stir components A and B before each processing step. Measure precisely according to the mixing ratio specified in the TDS (see comparison table above) – ideally by weight. Mix with an electric or pneumatic agitator at low speed (minimize air entrainment). Degas the mixture under vacuum (30–50 mbar) – the material will expand 3–4 times its original volume, bubbles will escape, and the material will settle back after 5–10 minutes. Then slowly pour into the mold from the lowest point to avoid air entrapment. For polyaddition systems, avoid contact with inhibitors (sulfur-based rubber, tin-based RTV, amine epoxides, PVC with tin salts).

Store in the unopened original container in a dry, cool place — typically between +5 and +30 °C, see TDS for exact values. Store components A and B separately; seal airtight after opening. Polyaddition systems are insensitive to moisture, but should be stored in a cool place to maintain pot life. Consult the Safety Data Sheet (SDS) before use.

The comparison table above lists related RTV products with different hardnesses, pot lives, or application profiles. If you are unsure which product is best for you, we would be happy to advise you — contact SILITECH with details of your application (substrate, desired hardness, processing time, mechanical requirements, and durability).

Your question isn't listed here

Our technical team will advise you personally on material selection, processing questions, and individual requirements. Quickly and competently.

Submit a request Request a sample

Product specifications

Product information
brand Bluesil
Manufacturer Elkem Silicones
Networking type Addition (Platinum)
Container 5 kg
Number of components 2K (two-component)
consistency Flowable
Mixing ratio 1:1
Other features
UV resistance No
Physical properties
Paint has hardened Blue
Self-leveling Yes
Viscosity uncrosslinked (mPa·s) 30
Electrical properties
Electrical insulation No
Curing values
Potting time (min) 3
Demolding time (min) 15
Product approvals
Food contact No
Suitable for medical use No
Mechanical properties
Tensile strength (MPa) 4
Elongation at break (%) 500
Tensile strength (N/mm) 15
Keywords
Keywords
Blue silicone BLUESIL thixotropic 2K silicone ELKEM Swiss bearing aviation RTV addition platinum catalyst protective coating boatbuilding 5 kg 1:1 RTV 3720 vacuum bag vacuum pouch composite VARTM infusion slow-cure SC casting application
Mechanical properties
Linear shrinkage< 0.1 %
processing
Viscosity Comp. A40,000 mPa·s
Viscosity Comp. B40,000 mPa·s
Pot life at 23°C60.0 min
demolding time150.0 min
Physical & Thermal
Density (23°C)1.1 g/cm³
Temperature resistance (duration)-50 to 200 °C
Peak temperature (short-term)200 °C
storage
Shelf life in original packaging12 months
Storage temperature-5 to 30 °C