Changing a PVC pipe typically involves a few steps, contingent upon whether you're replacing a section or the entire pipe. First, shut off the water supply. Use a hacksaw, or a PVC cutter, to cut out the damaged section or the whole pipe, ensuring the cuts are straight. Clean the edges of the remaining pipe(s) and the new pipe with PVC primer. Then, apply PVC cement on both the inside of the fittings and the outside of the pipes, and quickly join them together, fully inserting the pipe into the fitting until it's snug. Hold it in place for a few seconds to ensure a strong bond. For a full replacement, measure the new pipe carefully to fit the space. Always wear safety gear during these operations to avoid injuries from sharp tools or PVC cement fumes.

The cure time for PVC cement varies based on the product and environmental conditions but typically ranges between 15 minutes for initial set-up to 48 hours for full-strength bonding. PVC cement works by chemically fusing the PVC pipes and fittings together, so ensuring sufficient cure time is crucial for a reliable seal and pressure resistance. The temperature and humidity levels can significantly affect the cure time; warmer and more humid conditions can accelerate the curing process, while cooler or drier conditions can extend it. It's essential to check the manufacturer's instructions for specific cure times and recommendations. For projects under pressure systems, a minimum of 24 hours cure time is often advised before testing the system. Ensuring proper cure time is not only about the bond's strength but also about safety, especially in potable water and gas applications.

FDY yarn, or Fully Drawn Yarn, is a type of synthetic yarn widely used in the textile industry. It's produced through a spinning process that stretches the polymer chains to align in a parallel arrangement, enhancing the material's strength and stability. FDY is particularly appreciated for its evenness, high tensile strength, and smooth surface, making it ideal for producing fabrics that require a silky and soft finish like lingerie, sports apparel, and home textiles. Its versatility allows it to be blended with various fibers to create fabrics with specific desired properties, such as stretchability, breathability, or moisture-wicking abilities. As such, FDY yarn represents a crucial component in the manufacturing of high-quality, durable textile products.