ELASTOSIL® M 4115 A/B and MinghuiLink RTV-4115 are both very soft addition-cure silicones for flexible mold making, but they target different production needs. M 4115 A/B is optimized for low viscosity, rapid demolding and accurate reproduction of pronounced undercuts, while RTV-4115 offers a longer 35-minute working time, slightly softer 15 Shore A hardness and substantially higher published tensile and tear strength for more demanding repeated handling.
Addition-Cure Silicone
Platinum-Cure Silicone
ELASTOSIL® M 4115 A/B and RTV-4115 are both very soft mold silicones, but they suit different production priorities. M 4115 A/B is better suited to rapid mold turnaround, low-viscosity pouring and pronounced-undercut reproduction. RTV-4115 is better suited to users who need a longer working window, slightly lower hardness and substantially higher published tensile and tear strength for repeated handling.
ELASTOSIL® M 4115 A/B and RTV-4115 are both very soft addition-cure silicone systems for flexible reusable molds. WACKER lists M 4115 A/B at 17 Shore A, while MinghuiLink lists RTV-4115 at 15 Shore A. The small hardness difference is less important than the differences in working time, demolding speed, viscosity and mechanical strength.
M 4115 A/B is positioned by WACKER for accurate reproduction and models with pronounced undercuts. Its low component viscosity of approximately 2,500 mPa·s, combined with a fast published demoldable time of about 60 minutes, makes it attractive for fine-detail molds and applications where rapid mold turnaround is important. RTV-4115 uses the same 1:1 mixing system but provides a much longer 35-minute working time.
The working-time and curing profiles create the clearest production trade-off. M 4115 A/B has only about 12 minutes of pot life, so mixing and pouring must be completed quickly, but the mold can reach a demoldable state much sooner. RTV-4115 provides nearly three times the working time, making it easier for manual mixing, degassing and controlled pouring, but its published cure time is approximately 5 hours.
Mechanical properties favor RTV-4115 on the published numerical data. M 4115 A/B lists approximately 3.0 MPa tensile strength, 5 N/mm tear strength and 400% elongation, compared with 5.0 MPa, 26 N/mm and 450% respectively for RTV-4115. This gives RTV-4115 a substantially stronger published mechanical profile, particularly for thin mold edges, repeated peeling and frequent handling.
For difficult demolding, both products remain viable because they are very soft silicones. M 4115 A/B has a specific WACKER positioning for pronounced undercuts and combines 17 Shore A hardness with low viscosity and rapid demolding. RTV-4115 is slightly softer at 15 Shore A and has higher elongation, so it may be preferable where a longer processing window and greater flexibility are more important than rapid turnaround.
Both materials are suitable for detailed flexible molds, but very soft silicone may require external support for large molds or heavy castings. RTV-4115 also publishes a heat-resistance specification of up to 250°C / 482°F, while no equivalent numerical long-term service-temperature value is listed in the referenced WACKER information. As with other addition-cure silicones, compatibility testing is recommended for unfamiliar masters, coatings and 3D-printed surfaces.
Overall, ELASTOSIL® M 4115 A/B is better aligned with rapid mold production, low-viscosity pouring and explicitly difficult undercut reproduction. RTV-4115 is better aligned with longer manual processing time, slightly softer flexibility and substantially higher published tensile and tear strength.
| Technical Parameter | WACKER ELASTOSIL® M 4115 A/B | MinghuiLink RTV-4115 |
|---|---|---|
| Silicone Type | Addition-cure RTV-2 | Platinum-cure silicone |
| Color | Translucent | Translucent |
| Specific Gravity | 1.05 g/cm³ | 1.03–1.05 g/cm³ |
| Mix Ratio | 1:1 by weight | 1:1 by weight or volume |
| Shore Hardness | 17 Shore A | 15 Shore A |
| Viscosity | 2,500 mPa·s (Part A) | 4,000 mPa·s* (Part A) |
| Working / Pot Life | 12 min | 35 min |
| Demold / Cure Time | 60 min demoldable | 5 h cure |
| Tensile Strength | 3.0 MPa | 5.0 MPa |
| Tear Strength | 5 N/mm | 26 N/mm |
| Elongation | 400% | 450% |
| Shrinkage | No chemical shrinkage | ≤0.1% |
| Temperature Resistance | Not publicly listed | Up to 250°C / 482°F |
| Typical Applications | Flexible mold making, reproduction molding and models with pronounced undercuts | Soft flexible molds, detailed casting molds and general soft mold-making applications |
| Technical Data Sources | ELASTOSIL® M 4115 A/B | RTV-4115 |
| Key Factor | WACKER ELASTOSIL® M 4115 A/B | MinghuiLink RTV-4115 | What It Means |
|---|---|---|---|
| Hardness | 17 Shore A | 15 Shore A | RTV-4115 is slightly softer, while M 4115 A/B provides slightly more mold body. |
| Component Viscosity | 2,500 / 2,500 mPa·s | 4,000 / 2,800 mPa·s | M 4115 A/B publishes lower and more balanced component viscosities for easy pouring. |
| Working Window | 12 min | 35 min | RTV-4115 gives operators substantially more time for mixing, degassing and pouring. |
| Demold Speed | 60 min demoldable | 5 h cure | M 4115 A/B is better suited to applications where rapid mold turnaround is important. |
| Tensile Strength | 3.0 MPa | 5.0 MPa | RTV-4115 publishes substantially higher tensile strength. |
| Tear Strength | 5 N/mm | 26 N/mm | RTV-4115 publishes substantially higher tear strength, important for thin edges and repeated handling. |
| Elongation | 400% | 450% | RTV-4115 publishes higher elongation while both materials remain highly flexible. |
| Undercut Positioning | Specifically positioned for pronounced undercuts | Suitable for flexible undercuts | M 4115 A/B has the stronger explicit manufacturer positioning for difficult undercut reproduction. |
| Shrinkage | No chemical shrinkage | ≤0.1% | Both are positioned for accurate replication, using different published shrinkage descriptions. |
| Heat Resistance | Not publicly listed | 250°C / 482°F | RTV-4115 provides the clearer numerical high-temperature specification. |
| Application | ELASTOSIL® M 4115 A/B | RTV-4115 | Key Consideration |
|---|---|---|---|
| Pronounced Undercuts | Strong candidate | Strong candidate | Both are very soft materials; WACKER specifically positions M 4115 A/B for pronounced undercuts and easy demolding. |
| Fine-Detail Reproduction | Strong candidate | Strong candidate | M 4115 A/B has lower published component viscosity, while RTV-4115 provides a longer working window for controlled pouring. |
| Rapid Mold Production | Strong candidate | Suitable | M 4115 A/B reaches a published demoldable state in approximately 60 minutes. |
| Large / Complex Mold Preparation | Suitable with fast processing | Strong candidate | RTV-4115 provides approximately 35 minutes of working time versus 12 minutes for M 4115 A/B. |
| Thin Mold Edges | Suitable | Strong candidate | RTV-4115 publishes much higher tear strength, providing a stronger numerical profile for thin or repeatedly flexed edges. |
| Repeated Demolding | Suitable | Strong candidate | RTV-4115 publishes higher tensile and tear strength, while M 4115 A/B offers faster turnaround. |
| General Flexible Molds | Strong candidate | Strong candidate | Both provide very soft, flexible mold profiles; selection depends mainly on processing time and mechanical requirements. |
| Large Soft Molds | Suitable with support | Suitable with support | Both are very soft materials and may require a mother mold or support shell for heavy or large castings. |
| High-Temperature Casting | Suitable with temperature validation | Strong candidate | RTV-4115 publishes a numerical heat-resistance specification of up to 250°C / 482°F. |
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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.