ELASTOSIL® M 4644 A/B and MinghuiLink RTV-4140 are both around 40 Shore A, but their strengths are different. M 4644 is specifically positioned for vacuum casting, reproduction molds and undercut models, with a 90-minute working time. RTV-4140 offers simpler 1:1 mixing, much lower published component viscosity and faster published curing.
Addition-Cure Silicone
Platinum-Cure Silicone
ELASTOSIL® M 4644 A/B and RTV-4140 target a similar 40 Shore A range, but they suit different workflows. M 4644 is the better fit for vacuum casting, reproduction molds, undercuts and applications needing a long working window. RTV-4140 is better suited to users who prioritize simple 1:1 processing, lower viscosity and faster routine production.
ELASTOSIL® M 4644 A/B and RTV-4140 are closely matched at around 40 Shore A, so hardness is not a major selection factor. The more important differences are processing, mechanical properties and application focus.
M 4644 uses a 10:1 mix ratio with a 90-minute pot life, while RTV-4140 uses a simpler 1:1 system with approximately 35 minutes of working time. M 4644 therefore gives more time for large or complex molds, while RTV-4140 is easier to proportion for manual production.
Viscosity strongly favors RTV-4140 for routine handling. M 4644 publishes approximately 70,000 mPa·s for Part A and 500 mPa·s for Part B, with 50,000 mPa·s mixed viscosity. RTV-4140 publishes approximately 4,800 mPa·s Part A and 4,300 mPa·s Part B, making it substantially easier to pour and process manually.
Mechanical performance is mixed. M 4644 publishes approximately 5.5 MPa tensile strength, >25 N/mm tear strength and 400% elongation, while RTV-4140 publishes 5.3±0.5 MPa, 32±0.5 N/mm and 220%. M 4644 offers higher elongation, while RTV-4140 provides higher published tear strength.
M 4644 has the stronger application-specific positioning for vacuum casting, reproduction molds, undercuts and polyurethane or epoxy casting. RTV-4140 is better suited to users who prioritize simple 1:1 processing, lower viscosity and faster routine production.
| Technical Parameter | WACKER ELASTOSIL® M 4644 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 | 70,000 mPa·s (Part A) | 4,800±200 mPa·s (Part A) |
| Working / Pot Life | 90 min | 35 min |
| Demold / Cure Time | 12 h tack-free | 6 h cure |
| Tensile Strength | 5.5 MPa | 5.3±0.5 MPa |
| Tear Strength | >25 N/mm | 32±0.5 N/mm |
| Elongation | 400% | 220% |
| 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 4644 A/B | RTV-4140 |
| Key Factor | WACKER ELASTOSIL® M 4644 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 | 90 min | 35 min | M 4644 provides substantially more processing time. |
| Component Viscosity | 70,000 / 500 mPa·s | 4,800 / 4,300 mPa·s | RTV-4140 has much lower and more balanced component viscosities. |
| Tensile Strength | 5.5 MPa | 5.3±0.5 MPa | The published tensile values are relatively close. |
| Tear Strength | >25 N/mm | 32±0.5 N/mm | RTV-4140 publishes the higher numerical tear-strength value. |
| Elongation | 400% | 220% | M 4644 publishes substantially higher elongation for flexible demolding. |
| Application Positioning | Vacuum casting, reproduction, undercuts and PU/epoxy casting | General high-hardness mold making and casting | M 4644 has the 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. |
| Application | ELASTOSIL® M 4644 A/B | RTV-4140 |
|---|---|---|
| Vacuum Casting | Strong candidate | Suitable |
| Complex Reproduction | Strong candidate | Strong candidate |
| Undercut Molds | Strong candidate | Suitable |
| Polyurethane Casting | Strong candidate | Suitable with testing |
| Epoxy Casting | Strong candidate | Suitable with testing |
| Large / Complex Molds | Strong candidate | Suitable |
| Thin Mold Edges | Strong candidate | Strong candidate |
| Rapid Routine Production | Suitable | 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.