ELASTOSIL® M 4645 A/B and MinghuiLink RTV-4140 are both 40 Shore A mold silicones with different processing profiles. M 4645 offers a longer 80-minute working time and specific positioning for vacuum casting, reproduction and polyurethane or epoxy molds, while RTV-4140 provides simpler 1:1 mixing, substantially lower component viscosity and faster routine curing.
Addition-Cure Silicone
Platinum-Cure Silicone
ELASTOSIL® M 4645 A/B and RTV-4140 target essentially the same 40 Shore A range, but they suit different production priorities. M 4645 is better suited to vacuum casting, complex reproduction and resin molds that benefit from a longer working window. RTV-4140 is better aligned with simple 1:1 processing, lower viscosity and faster routine production.
ELASTOSIL® M 4645 A/B and RTV-4140 are closely matched at 40 Shore A. M 4645 provides an approximately 80-minute working time, while RTV-4140 offers a simpler 1:1 mixing system and approximately 35 minutes of working time.
Viscosity is a major processing difference. M 4645 publishes approximately 50,000 mPa·s for Part A, 3,500 mPa·s for Part B and 35,000 mPa·s mixed, compared with 4,800±200 mPa·s Part A and 4,300±200 mPa·s Part B for RTV-4140. RTV-4140 therefore has substantially lower and more balanced component viscosities, while M 4645 provides more processing time.
Mechanical performance is mixed. M 4645 publishes approximately 5 MPa tensile strength, >28 N/mm tear strength and 330% elongation. RTV-4140 publishes 5.3±0.5 MPa tensile strength, 32±0.5 N/mm tear strength and 220±50% elongation. RTV-4140 has higher published tensile and tear values, while M 4645 provides greater elongation.
M 4645 has the more specific application positioning. WACKER identifies it for vacuum casting, reproduction molds, undercuts and polyurethane or epoxy casting, making it particularly relevant to demanding reproduction work. RTV-4140 is positioned more broadly for high-hardness reusable molds and routine casting applications.
Overall, M 4645 favors extended processing time, flexibility and specialized reproduction applications, while RTV-4140 favors simpler mixing, lower viscosity and faster routine processing.
| Technical Parameter | WACKER ELASTOSIL® M 4645 A/B | MinghuiLink RTV-4140 |
|---|---|---|
| Silicone Type | Addition-cure RTV-2 | Platinum-cure silicone |
| Color | Translucent | Translucent |
| Mix Ratio | 10:1 by weight | 1:1 by weight or volume |
| Shore Hardness | 40 Shore A | 40±1 Shore A |
| Viscosity | 50,000 mPa·s (Part A) | 4,800±200 mPa·s (Part A) |
| Working / Pot Life | 80 min | 35 min |
| Demold / Cure Time | 12 h tack-free | 6 h cure |
| Tensile Strength | 5 MPa | 5.3±0.5 MPa |
| Tear Strength | >28 N/mm | 32±0.5 N/mm |
| Elongation | 330% | 220±50% |
| Shrinkage | <0.1% | ≤0.1% |
| Temperature Resistance | Not publicly listed as an equivalent numerical service rating | Up to 250°C / 482°F |
| Typical Applications | Vacuum casting, reproduction molds, undercuts, polyurethane and epoxy casting | Reusable molds, rapid prototyping and general industrial casting |
| Technical Data Sources | ELASTOSIL® M 4645 A/B | RTV-4140 |
| Key Factor | WACKER ELASTOSIL® M 4645 A/B | MinghuiLink RTV-4140 | What It Means |
|---|---|---|---|
| Hardness | 40 Shore A | 40±1 Shore A | Both target essentially the same hardness range. |
| Mix Ratio | 10:1 | 1:1 | RTV-4140 is simpler for manual batching. |
| Working Time | 80 min | 35 min | M 4645 provides substantially more processing time for large or complex molds. |
| Component Viscosity | 50,000 / 3,500 mPa·s | 4,800 / 4,300 mPa·s | RTV-4140 publishes much lower and more balanced component viscosities. |
| Mechanical Profile | 5 MPa tensile; >28 N/mm tear; 330% elongation | 5.3±0.5 MPa tensile; 32±0.5 N/mm tear; 220±50% elongation | RTV-4140 has higher published tensile and tear values; M 4645 provides greater elongation. |
| Application Positioning | Vacuum casting, reproduction, undercuts and PU/epoxy casting | General high-hardness mold making and industrial casting | M 4645 has more specific reproduction and casting-resin positioning. |
| Mold Turnaround | 12 h tack-free | 6 h cure | RTV-4140 is better aligned with faster published routine curing. |
| Processing Priority | Longer working window and specialized reproduction | Simpler mixing, lower viscosity and faster turnaround | The main choice is between processing time and handling efficiency. |
| Application | ELASTOSIL® M 4645 A/B | RTV-4140 |
|---|---|---|
| Complex Reproduction | Strong candidate | Strong candidate |
| Undercut Molds | Strong candidate | Suitable |
| Large / Complex Molds | Strong candidate | Suitable |
| Vacuum Casting | Strong candidate | Strong candidate |
| Polyurethane / Epoxy Casting | Strong candidate | Strong candidate |
| Rapid Routine Production | Suitable | Strong candidate |
| Manual Small-Batch Mixing | Suitable with accurate weighing | Strong candidate |
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Competitor specifications are based on publicly available manufacturer documentation, with links to the original sources where available. Missing values are shown as “Not publicly listed” and are not estimated or inferred. Specifications may change, so always check the latest manufacturer documentation and conduct application-specific testing before production use. Product names and trademarks belong to their respective owners. This comparison is provided for technical and informational purposes only and is not endorsed by the brands mentioned.