Washing sheep wool for insulation involves a careful process to remove dirt, grease (lanolin), and debris while preserving the wool's structure and insulating properties. Here's a detailed guide:
1. Pre-Washing Preparation:
- Sorting: Separate the fleece into different qualities. Coarse wool may be suitable for rugs or other applications, while finer wool is better for insulation. Remove any obviously dirty or matted sections.
- Picking: Hand-pick any large pieces of vegetable matter (VM) like burrs, sticks, and seeds. While some VM is acceptable in insulation, large quantities can reduce its effectiveness and increase the risk of mold.
2. Washing Process:
- Water Temperature: Use hot, but not boiling, water (around 120-140°F or 49-60°C). Too hot, and the wool can felt, matting the fibers together and reducing its loft.
- Detergent: Use a gentle, pH-neutral detergent specifically designed for wool or delicate fabrics. Avoid harsh chemicals or detergents with enzymes, as these can damage the wool fibers. Dish soap can be used in a pinch but may strip more lanolin than desired.
- Washing Method:
- By Hand (Recommended for Small Batches): Fill a large tub or sink with hot water and detergent. Gently submerge the wool, pressing it down to saturate it. Let it soak for 15-30 minutes, allowing the dirt and grease to loosen. Avoid agitating the wool, as this can cause felting. Drain the dirty water and repeat the process with clean water and detergent until the water runs clear.
- Washing Machine (Use with Caution): If using a washing machine, choose the "delicate" or "wool" cycle with cold or lukewarm water and a slow spin speed. Place the wool in a mesh laundry bag to help prevent felting. Do not agitate the wool excessively. It is preferable to only let it soak in the washing machine and then drain it.
- Rinsing: Rinse the wool thoroughly with clean, hot water until all traces of detergent are gone. Avoid sudden temperature changes during rinsing, as this can also cause felting.
3. Drying:
- Gentle Handling: Carefully remove the wool from the water, supporting its weight to prevent stretching.
- Removing Excess Water: Gently squeeze out excess water. Do not wring the wool, as this can damage the fibers. You can also roll the wool in a towel to absorb excess water.
- Drying Method:
- Air Drying: Lay the wool flat on a clean, dry surface, such as a screen or a towel-covered table, in a well-ventilated area. Turn the wool periodically to ensure even drying. Avoid direct sunlight or heat, as this can make the wool brittle.
- Low Heat Drying (Less Recommended): A dryer can be used if it has a no-heat or very low-heat setting and tumble it, but this is risky and more likely to cause felting.
4. Optional Treatments:
- Borax (Fire Retardant): Borax can act as a fire retardant. After washing (or once almost dry), dissolve Borax in hot water to create a solution. Spray the wool with this solution as it lays out to dry. Do not rinse it out. The ratio would depend on the intended use but aim for full saturation.
- Lanolin Replenishment (Optional): Washing removes lanolin, the natural oil that protects wool. While not essential for insulation, a small amount of lanolin can help improve its water resistance. You can add a small amount of lanolin back to the wool during the rinsing process by dissolving it in hot water and adding it to the final rinse.
Important Considerations:
- Felting: Felting is the biggest risk when washing wool. It occurs when the wool fibers become interlocked and matted together. Avoid excessive agitation, high temperatures, and sudden temperature changes to prevent felting.
- Lanolin: Lanolin is the natural grease found in sheep's wool. Washing removes lanolin. Some lanolin is good because of its water-resistant qualities; it can be replenished using commercially available products but isn't strictly necessary for insulation.
- Cleanliness: Ensure the wool is thoroughly cleaned to remove dirt, grease, and debris. This will improve its insulating properties and reduce the risk of odor or pest infestations.
