PlatSil Gel-25 – Platinum-Cure Silicone Gel for Mould Making & Prototyping

Premium Platinum-Cure Silicone Gel for Professional Applications

PlatSil Gel-25 is a firm, platinum-cured silicone gel from Polytek Development Corp. with a Shore A25 hardness — the most dimensionally stable variant in the PlatSil Gel line. With a low viscosity of 3,500 cP and a simple 1A:1B mix ratio (by weight or volume), this system is ideally suited to detailed moulds, prototyping and industrial casting applications.

Key Benefits

• Certified skin safe: Polytek has this product independently assessed as skin safe, in accordance with FHSA (16 CFR 1500), LHAMA (16 CFR 1500.14), ASTM D4236 and Sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act.
• High dimensional stability: Shore A25 hardness for moulds that require dimensional accuracy in repeated use.
• Low viscosity: 3,500 cP for excellent detail reproduction and easy pouring without vacuum equipment.
• High mechanical strength: 434 psi tensile strength and 146 pli tear strength (Die B) for long service life in production environments.
• Adjustable hardness: Part H Hardener raises the Shore hardness to A40 for firmer applications.
• Broad accessory ecosystem: Compatible with PlatThix (thickener), SiliColors (pigments), Part X Accelerator and Part R Retarder.

Typical Applications

• Mould making of industrial models with high detail accuracy
• Prototyping of rigid flexible parts in product design and engineering
• Casting of polyurethane, epoxy and polyester resin in production runs
• SFX and theatrical prosthetics where firmness and edge definition are required
• Educational and artistic sculpture moulds for repeated use
• Automotive and industrial applications where dimensional stability is essential

Technical Characteristics

PlatSil Gel-25 is mixed in a 1A:1B ratio by weight or volume, with a pour time of 5 minutes and a demould time of 60 minutes at 73°F. Shore hardness: A25. Viscosity: 3,500 cP. Elongation: 385%. Tensile strength: 434 psi. Tear strength: 146 pli (Die B), 28 pli (Die T). Cured colour: milky white. Specific gravity: 1.1. Store at 15–32°C in unopened original packaging; use within six months. Source: Polytek Technical Bulletin PlatSil® Silicone Gels, V4 (06-02-2024).

Food contact

Polytek states for PlatSil Gel-25: "tested by an independent laboratory and was found to comply with 21 CFR 177.2600 (as published in the Code of Federal Regulations) for rubber articles intended for repeated use food contact surfaces when accurately measured, thoroughly mixed, and fully cured." This concerns a repeated-use food contact surface — that is, the mould itself.

Read the conditions alongside it. The statement applies only when the material is accurately measured, thoroughly mixed and fully cured. Any addition — Deadener, Part H Hardener, PlatThix, Part R, Part X or pigment — takes the mixture outside the tested composition.

21 CFR 177.2600 is US legislation. For this product there is no declaration of compliance under Regulation (EC) 1935/2004, no assessment against BfR Recommendation XV and no § 31 LFGB report. Polytek does not name the laboratory or the test date, and the statement appears on Polytek's product page and in its catalogue, not in the technical bulletin. If you need substantiation for the European market, look at Silicone Culinair (tested by TÜV Rheinland in accordance with § 31 LFGB, result Pass).

Polytek Development Corp. is an American specialist in polyurethane and silicone systems for professional mould making, life casting and industrial applications, with over 40 years of experience in the sector.

Professional Support

Do you have technical questions about the right formulation, additives or processing conditions for your specific application? Our team is ready with product-specific advice based on your project. Contact us for personal guidance.