Description
This durable urethane mold rubber is designed for production casting of concrete.
Formlastic™ 48 features low viscosity for easy mixing and pouring, curing with minimal bubble entrapment.
The mix ratio is 1A:1B by volume, with a working time of 25 minutes, and it cures to an ultimate Shore hardness of 48A.
The cured rubber is dimensionally stable, with low shrinkage, and it offers good wear resistance, and provides color-accurate concrete castings.
Importantly, it does not contain crystalline silica.
Technical Properties
- Mix Ratio by Volume: 1A:1B
- Mix Ratio by Weight: 100A:118B
- Working time: 25 minutes
- Cure Time: 24 hours
- Shore Hardness: 48A
- Specific Gravity: 1.14 g/cc
- Specific Volume: 0.88 cm³/g
- Color: Off White
- Tensile Strength: 4.83 MPa
- 100% Modulus: 765 kPa
- Elongation @ Break: 1,250%
- Die C Tear Strength: 17.2 kN/m
- Mixed Viscosity: 3,000 mPa·s
Use Cases
Suitable for creating molds for concrete casting, particularly in applications requiring durability and color accuracy.
Instructions
Preparation
Store and use at room temperature (23°C). These products have a limited shelf life and should be used as soon as possible. Environmental humidity should be as low as possible. Good ventilation (room size) is essential. Wear safety glasses, long sleeves, and rubber gloves to minimize contamination risk.
Sealing Materials
Models with porous surfaces (gypsum plasters, concrete, wood, stone, etc.) must be sealed prior to applying a release agent. Sonite™ Wax is a proven sealer for porous surfaces. Non-porous surfaces like metal, glass, hard plastics, and sulfur-free clays require only a release agent.
Applying A Release Agent
Use a release agent made specifically for mold making (Universal™ Mold Release). A liberal coat should be applied onto all surfaces that will contact the rubber. Lightly brush the release agent with a soft brush over all surfaces of the model, follow with a light mist coating, and let the release agent dry for 30 minutes. A small test application is recommended if performance is in question.
Measuring & Mixing
Liquid urethanes are moisture sensitive and will absorb atmospheric moisture. Mixing tools and containers should be clean and made of metal or plastic. Materials should be stored and used in a warm environment (23°C). Pre-mix Part B before using. Using a flat edge paddle or a drill mixer, scrape sides and bottom of the container several times.
Pouring
For best results, pour your mixture in a single spot at the lowest point of the containment field. Let the rubber seek its level up and over the model. A uniform flow will help minimize entrapped air. The liquid rubber should level off at least 1.3 cm (1/2”) over the highest point of the model surface.
Curing & Performance
Allow rubber to cure a minimum of 24 hours at room temperature (23°C) before using. Cure time can be reduced with mild heat or by adding Smooth-On Kick-It™ Cure Accelerator. Do not cure rubber where temperature is less than 18°C. Post curing is optional; following a 24-hour cure, heating the rubber to 65°C for 4 to 8 hours will increase physical properties and performance.
Using The Mold
A release agent should be applied to the mold before each casting. Aquacon™ Water Based Release Agent is recommended for releasing abrasive materials like concrete.
Performance & Storage
Fully cured rubber is tough, durable, and will perform if properly used and stored. Molds should be stored on a level surface at room temperature in a dry environment. Do not stack molds, expose them to moisture, or UV light for prolonged periods.
Safety and Handling
For industrial use only. Keep out of the reach of children.
