Zircon and Iridium platings are expensive for several reasons.

1. Rarity: Both Zircon and Iridium are not as common as metals like iron, copper or aluminum, making them more expensive to source. Iridium is one of the rarest elements in the Earth's crust.

2. Difficulty in Mining and Refining: Extracting and refining these metals from their ores require complex and costly industrial processes.

3. High Performance Characteristics: Both Zircon and Iridium have specific characteristics that make them beneficial for certain uses. For example, iridium is extremely corrosion-resistant and has a very high melting point, making it ideal for use in extreme conditions such as in aircraft engine components. Zirconium is highly resistant to heat and corrosion, making it ideal for use in industries such as aerospace and defense. These high performance characteristics boost their industrial demand, consequently raising the price.

4. Market Factors: Other factors such as market speculation, political instability in producing countries, trade restrictions, and changing supply and demand dynamics can also contribute to the price of these metals.

When choosing the most durable yarn for slippers, wool is often considered the best option due to its sturdy nature and the ability to withstand wear and tear. Specifically, wool blends that incorporate synthetic fibers, like nylon, enhance durability further while maintaining the warmth and comfort wool provides. Wool is also naturally moisture-wicking, which adds to its suitability for slipper making. Superwash wool, treated to prevent shrinking and felting, is particularly user-friendly for easy care. For those seeking vegan or non-allergenic alternatives, acrylic yarns can be a durable and easy-care option, though they may not offer the same warmth or natural feel as wool.

After gluing PVC pipes, it's crucial to wait for the adhesive to fully cure before subjecting the joint to any pressure or use. Typically, the initial set time for PVC glue can be as quick as 2 to 5 minutes, allowing you to handle the joint with care. However, for the adhesive to fully cure and achieve its maximum strength, a waiting period of 15 minutes to 24 hours is recommended, depending on the glue brand, pipe diameter, and environmental conditions like temperature and humidity. For critical or high-pressure applications, following the longer end of recommended curing times is wise to ensure a secure and leak-proof connection.