Polytek Poly 74-29 Liquid Rubber is a top - notch two - part liquid polyurethane system. It cures (RTV) to a Shore A30 rubber. This rubber offers durability and long - lasting performance. Thanks to the excellent strength and elongation of the cured rubber, you can create high - quality molds. It comes in a pourable liquid form that cures to soft to mid - range hardnesses. You can easily thicken it for brush - on applications. When casting many plasters, waxes, and concretes, you don't need to use release agents. Its low - viscosity allows it to capture every detail from intricate masters. Technical Specifications Mix Ratio by Weight: 1A:1B. Shore Hardness: A30. Pour Time: 30 min. Demold Time: 16 hr. Cured Color: Black. Mixed Viscosity: 2,800 cP. Specific Volume: 27.5 in³/lb. Specific Gravity: 1.02. Elongation: 1,600 %. Tensile Strength: 520 psi. Die C Tear Strength: 109 pli. Notes: Before using, shake or stir Part B. The color of polyurethane Part B may vary from batch to batch or darken over time, but this won't affect the product performance. For more details, check the safety data sheet and material calculator on the manufacturer's website: https://polytek.com/products/poly - 74 - 29 - liquid - rubber. Brand: Polytek

Using Polytek Poly 74 - 29 Liquid Rubber is easy. First, make sure to shake or stir Part B well before use. Then, mix Part A and Part B in a 1:1 ratio by weight. Once mixed, you have about 30 minutes to pour it onto your master. If you want to use it for brush - on applications, you can thicken it easily. After pouring, wait for 16 hours until you can demold. The cured rubber is black and has great strength and elongation, which makes it perfect for making durable molds. When casting plasters, waxes, or concretes, you don't need to use any release agents. As for maintenance, keep it in a cool and dry place. The color of Part B may change a bit over time, but don't worry, it won't affect how well the rubber works. For more safety and material - related information, visit the manufacturer's website.