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BLUESIL RTV 3221 without catalyst
BLUESIL® RTV 3221 (known as RTV 573) – Soft-elastic silicone rubber for durable negative molds and fine structures
2K-Sn silicone (polycondensation) for highly elastic molds — lost-wax casting process, fashion jewelry, art and special effects
Documents
Internal reference:
40-927
HS code:
39100000
Bluesil RTV 3221 is a 2K-Sn silicone (polycondensation) for highly elastic molds — lost-wax casting process, fashion jewelry, art and special effects.
This product line comprises 2K polycondensation silicone elastomers (tin-catalyzed) for mold making — established, economical industrial chemistry with good substrate compatibility, especially for lost-wax casting, decoration, and construction. RTV 3221 is tailored to specific industrial applications — the most important properties and areas of application are listed below.
Bluesil RTV 3221 was specially developed for highly elastic molds — Shore A 18 with elongation at break 230%. Its low modulus facilitates the demolding of delicate originals. Available with two catalyst options: standard (24 h) or fast (6 h).
What makes the RTV 3221 stand out
What is the RTV 3221 used for?
processing
Recommended accessories
Important instructions
RTV 3221 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 3221 Current product |
RTV 3318 SPU → | RTV 3325 → | RTV 3430 SB → | |
|---|---|---|---|---|
| Networking system | 2K Condensation (Sn) | 2K Condensation (Sn) | 2K Condensation (Sn) | 2K Polyaddition (Pt) |
| Mixing ratio | 100 : 5 (Cata) | 100 : 5 (CATA SPU) | 100 : 5 (Cata) | 10 : 1 |
| Color | Beige | White | White | Transparent / grey (B) |
| Shore A hardness | A 18 | A 18 | A 25–28 | A 28 |
| Elongation at break | 230 % | 520 % | 440–490 % | 600 % |
| Tensile strength | 1.6 MPa | 3.3 MPa | 4–4.3 MPa | 6 MPa |
| Tear resistance | — | 19 kN/m | 21–26 kN/m | 20 kN/m |
| Potting time | 30 min (Standard) / 20 min (Fast) | 90–150 min | 90–150 min (hr) | 1 h |
| demolding time | 24 h (Standard) / 6 h (Fast) | 24 h | 24 h (Standard) / 6 h (Fast) | 10 h |
| Mixed viscosity | 15,000 mPa·s | 25,000 mPa·s | 35,000 mPa·s | 20,000 mPa·s |
| Main application | Lost wax casting for art casting | Polyurethane casting resin molds | lost-wax molds | Concrete components (construction) |
Technical data for BLUESIL RTV 3221 without catalyst
| Product information | |
|---|---|
| Manufacturer | Elkem Silicones |
| Networking type | Condensation (tin) |
| Number of components | 2K (two-component) |
| consistency | Flowable |
| brand | Bluesil |
| Container | 1kg, 5kg, 20kg, 25kg, 200kg |
| Mixing ratio | 100:5 |
| Other features | |
|---|---|
| UV resistance | No |
| Physical properties | |
|---|---|
| Paint has hardened | Beige |
| Self-leveling | Yes |
| Density (g/cm³) | 1.3 |
| Viscosity uncrosslinked (mPa·s) | 15 |
| Electrical properties | |
|---|---|
| Electrical insulation | No |
| Curing values | |
|---|---|
| Potting time (min) | 30 |
| Demolding time (min) | 24 |
| Product approvals | |
|---|---|
| Food contact | No |
| Suitable for medical use | No |
| Mechanical properties | |
|---|---|
| Tensile strength (MPa) | 1.6 |
| Elongation at break (%) | 230 |
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
Frequently asked questions about RTV 3221
Practical questions regarding processing and design — answered by SILITECH.
Bluesil RTV 3221: 2K sn silicone (polycondensation) for highly elastic molds — lost-wax casting, fashion jewelry, art, and special effects. Main applications include lost-wax casting for art casting, fashion jewelry reproduction, and special effects (SFX).
Polycondensation crosslinking is a two-component silicone chemistry using a tin catalyst. Upon mixing, the components crosslink, releasing alcohol as a byproduct—this can lead to a small linear shrinkage (typically <0.7%). Advantages: Polycondensation silicones are less sensitive to inhibitors than polyaddition systems—they crosslink even in contact with sulfur-vulcanized rubber and are tolerant of many substrates. It is an established, economical industry standard for lost-wax casting, decorative reproduction, and construction.
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).
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Product specifications
| Product information | |
|---|---|
| Container | 1kg or 5kg or 20kg or 25kg or 200kg |
| Manufacturer | Elkem Silicones |
| Networking type | Condensation (tin) |
| Number of components | 2K (two-component) |
| consistency | Flowable |
| brand | Bluesil |
| Mixing ratio | 100:5 |
| Other features | |
|---|---|
| UV resistance | No |
| Physical properties | |
|---|---|
| Paint has hardened | Beige |
| Self-leveling | Yes |
| Density (g/cm³) | 1.3 |
| Viscosity uncrosslinked (mPa·s) | 15 |
| Electrical properties | |
|---|---|
| Electrical insulation | No |
| Curing values | |
|---|---|
| Potting time (min) | 30 |
| Demolding time (min) | 24 |
| Product approvals | |
|---|---|
| Food contact | No |
| Suitable for medical use | No |
| Mechanical properties | |
|---|---|
| Tensile strength (MPa) | 1.6 |
| Elongation at break (%) | 230 |
| Keywords | |
|---|---|
| Keywords | |
| Mechanical properties | |
|---|---|
| Shore hardness A | 18.0 Shore A |
| Tensile strength | 1.6 MPa |
| Elongation at break | 235.0 % |
| Linear shrinkage | < 1.2 % |
| processing | |
|---|---|
| Viscosity Comp. A | 15,000 mPa·s |
| Pot life at 23°C | 30.0 min |
| demolding time | 1440.0 min |
| Physical & Thermal | |
|---|---|
| Density (23°C) | 1.3 g/cm³ |
| Temperature resistance (duration) | -50 to 200 °C |
| Peak temperature (short-term) | 250 °C |
| storage | |
|---|---|
| Shelf life in original packaging | 12 months |
| Storage temperature | -5 to 30 °C |
Documents and datasheets
Safety Data Sheets (SDS) and Technical Data Sheets (TDS) are available for download:
- Bluesil RTV 3221 without catalyst - Technical Data Sheet FR.pdf (169 KB)
- Bluesil RTV 3221 without catalyst - Fiche de Sécurité FR.pdf (43 KB)
- Bluesil RTV 3221 without catalyst - Safety Data Sheet EN.pdf (40 KB)
- Bluesil RTV 3221 without catalyst - Safety Data Sheet DE.pdf (42 KB)
- Bluesil RTV 3221 without catalyst - Technical Data Sheet EN.pdf (144 KB)
- Bluesil RTV 3221 without catalyst - Technical data sheet DE.pdf (155 KB)