Addition Cure Mold Silicone Rubber HY-E625 | 25 Shore A Plati

1. Product Overview

Shenzhen Hong Ye Jie Technology Co., Ltd. presents HY-E625, a high-performance addition-cure (platinum-catalyzed) liquid silicone rubber specially formulated for architectural GRC and decorative concrete mold making. With a cured hardness of 25 Shore A and a translucent appearance, HY-E625 offers an ideal balance of flexibility, elasticity, and structural support — exactly what is required for demolding complex architectural profiles without tearing or distortion.

The architectural decorative concrete industry is booming globally. Architects and designers increasingly specify precast GRC components, ornamental concrete panels, and cast stone elements for facades, interiors, and landscaping. These products demand molds that can faithfully reproduce fine surface texture — from delicate stone veining to crisp ornamental relief — while withstanding repeated casting with heavy cementitious materials.

Traditional mold materials such as plaster, glass fiber, and condensation-cure silicone present serious limitations: plaster molds break easily and capture limited detail; glass fiber molds are costly and slow to produce; condensation-cure silicone suffers from higher shrinkage (0.3%–0.5%), strong odor, and short mold life. HY-E625 solves these problems through platinum-catalyzed addition curing, achieving near-zero shrinkage (≤0.1%), outstanding tear resistance (≥22 kN/m), excellent elongation (≥400%), and a mold life of 800+ casting cycles — making it the preferred material for professional architectural concrete mold making.

The 25 Shore A hardness is a sweet spot for architectural applications: soft enough to release complex undercuts and ornate profiles easily, yet firm enough to hold its shape when casting heavy concrete and GRC. The translucent body allows technicians to observe air entrapment and pouring flow, significantly improving first-pass mold quality.

2. Core Advantages

2.1 Near-Zero Shrinkage for Precision Architectural Dimensions Addition curing releases no volatile by-products, delivering shrinkage of ≤0.1%. For a 1.5-meter GRC cornice section, dimensional deviation stays under 1.5 mm. This precision is critical for architectural elements that must align perfectly on site — panels, columns, and cornices that fit seamlessly during installation.

2.2 High Tear Strength for Complex Profiles With tear strength ≥22 kN/m and elongation ≥400%, HY-E625 safely releases ornate reliefs, deep undercuts, moldings, fluted columns, and decorative scrollwork. The flexibility to flex, stretch, and peel silicone from intricate profiles without tearing is the defining requirement for architectural ornament molds.

2.3 Superior Flowability & Micro-Detail Reproduction Viscosity of 18,000–24,000 cps with excellent self-leveling allows HY-E625 to flow into fine surface textures — stone grain, wood grain, embossed lettering, carved ornaments, and intricate relief details down to 0.05 mm. The result is concrete surfaces with crisp, faithful reproduction of the master pattern.

2.4 Extended Working Time for Large-Scale Casting With a 1:1 mix ratio, HY-E625 provides a 45–60 minute working time at 25°C, giving operators sufficient time to brush detail coats, layer silicone on large architectural masters, and eliminate air bubbles — essential for large molds weighing 20–100 kg of silicone.

2.5 Exceptional Durability in Cementitious Casting HY-E625 withstands the alkaline environment, abrasion, and thermal load of repeated GRC and concrete casting. With proper release agent application, mold life reaches 800–1,200+ cycles, dramatically reducing per-unit mold cost for high-volume precast production.

2.6 Weather & Chemical Resistance Service temperature range of -60°C to +200°C, plus resistance to UV, weathering, and the alkaline chemistry of cement, ensures stable performance in both the workshop and outdoor casting environments.

2.7 Non-Toxic & Odorless The platinum catalyst system is non-toxic and odor-free, improving workshop air quality and enabling in-situ casting at construction or renovation sites without disturbing occupants.

2.8 Full Certification for Global Projects Certified to ISO 9001, FDA, REACH, RoHS, UL, and CE, supporting export of architectural concrete products and mold-making services to global markets.

3. Technical Specifications

4. Step-by-Step Mold-Making Guide for Architectural Concrete

Step 1: Master Pattern Preparation Assess the architectural master (positive model) — its size, weight, material, undercuts, and surface texture. Clean thoroughly with neutral detergent, dry completely, and apply a suitable release agent. Critical warning: avoid sulfur-, tin-, or amine-based release agents, which poison the platinum catalyst. For porous plaster or foam masters, seal with a lacquer or epoxy sealer first.

Step 2: Designing the Parting Line Plan the parting line along the largest cross-section, keeping it away from primary visible surfaces. For large architectural elements such as columns or cornices, divide into 2–4 sections. Build clay dams along parting lines, set alignment keys (30–50 cm spacing), and construct a rigid containment frame leaving 1.5–2.5 cm clearance for the silicone layer.

Step 3: Weighing & Mixing Weigh Part A and Part B precisely at 1:1 ratio. Mix slowly in one direction for 3 minutes, scraping walls and bottom. For large batches (>5 kg), mix in multiple batches to avoid exceeding the working time.

Step 4: Vacuum Degassing Degas at -0.095 MPa for 3 minutes. The translucent material allows visual confirmation that all bubbles are removed.

Step 5: Brush Detail Coats Brush the first thin layer (approx. 1 mm) onto the finest details — stone veining, carved ornaments, lettering, surface texture. Allow to skin over (20–30 min) before applying subsequent layers.

Step 6: Layered Thickening Build up additional layers to a total thickness of 4–6 mm. For large architectural molds, embed fiberglass cloth or gauze between layers to enhance tear resistance and dimensional stability. Thicken high-stress areas (corners, base edges) to 8–10 mm.

Step 7: Mother Mold (Support Shell) After the silicone cures (4–6 hours), fabricate a fiberglass or plaster mother mold over the silicone surface. The mother mold must be rigid enough to support heavy concrete casting, with internal wooden or steel reinforcement and lifting points.

Step 8: Demolding & Inspection Remove the mother mold first, then peel the silicone mold from the master starting at parting-line edges. Use compressed air to help release stubborn areas. Inspect the mold interior for bubbles, tears, or defects; repair minor flaws with fresh silicone; register the mold number before production.

5. Casting GRC & Decorative Concrete with HY-E625 Molds

5.1 GRC (Glass-fiber Reinforced Concrete) Casting The most common application. Apply gel coat to the mold interior, then spray or hand-apply GRC mix (cement, sand, alkali-resistant glass fibers, admixtures) in layers. Cure 24–48 hours before demolding. HY-E625's alkaline resistance and dimensional stability make it ideal for GRC panel production.

5.2 Cast Concrete / Precast Elements For heavy cast concrete ornaments, place reinforcement, pour concrete carefully to avoid air pockets, vibrate, and cure under controlled conditions. HY-E625's firm-but-flexible body supports the concrete weight without distortion.

5.3 Plaster & Cast Stone For lighter architectural ornaments, plaster or cast stone (gypsum-based) can be cast in HY-E625 molds with excellent detail transfer and easy release.

5.4 Resin & Polyurethane For interior architectural decoration (cornices, ceiling roses, wall panels), epoxy or polyurethane resin can be cast, offering high surface finish.

6. Applications

• Architectural GRC panels & cladding — facade decoration, curtain-wall infill panels
• Ornamental cornices, moldings & balustrades — classical and contemporary profiles
• Columns, capitals & pilasters — fluted and ornate columns
• Fireplace surrounds & mantels — cast stone mantels and surrounds
• Planters, water features & garden ornaments — landscaping elements
• Artificial stone cladding — realistic stone veneer panels
• Themed architectural reliefs — interior/exterior wall relief panels, signage
• Heritage restoration — replica ornamental elements for historical buildings

7. Certifications & Ordering

• Certifications: ISO 9001, FDA, REACH, RoHS, UL, CE
• Packaging: 5 kg, 20 kg, 25 kg, 200 kg drums
• Storage: sealed, cool, dry, 12 months shelf life
• MOQ: 2 kg; free samples available
• Customization: hardness (10A–50A), viscosity, color, working time customizable

8. About Hong Ye Silicone

Founded in 1998, Shenzhen Hong Ye Jie Technology Co., Ltd. is a national high-tech enterprise specializing in R&D, production, and sales of silicone rubber. With a 6,000 m² modern production base and monthly capacity exceeding 220 tons, our products are exported to 138+ countries, serving architectural decoration, landscaping, precast concrete, and 20+ industries worldwide. Our technical team provides material selection, mold-making guidance, and custom formulation support.