Sewing polyurethane laminate (PUL) fabric requires a few specific techniques to handle its unique properties, such as its waterproof coating and stretch. By following these tips, you can achieve successful and durable seams.
Essential Tips for Sewing with PUL Fabric
Working with PUL fabric, which is essentially a layer of polyurethane film bonded to a fabric base, can be different from sewing standard woven or knit fabrics. The slick, sometimes sticky surface and the stretch require adjustments in your sewing process.
Here are key recommendations for sewing PUL on fabric, based on expert advice:
- Skip the Prewash: Unlike many other fabrics, you usually do not need to prewash PUL. This helps maintain the integrity of the waterproof layer.
- Use Pattern Weights: Instead of pins, which can damage the waterproof layer by creating permanent holes, use pattern weights to hold your pattern pieces in place while cutting.
- Clip, Don't Pin: When assembling fabric pieces for sewing, use sewing clips instead of pins. Pins will create holes in the waterproof coating, compromising its function.
- Iron with Care: If ironing is necessary, use a low heat setting and place a pressing cloth between the iron and the fabric, particularly on the polyurethane side, to prevent melting or damage. Test on a scrap piece first.
- Use a Ballpoint Needle: PUL often has a knit backing. A ballpoint needle (or stretch needle) is recommended as it pushes the fabric fibers aside rather than piercing them, which is better for stretch fabrics and can help prevent damage to the waterproof layer and avoid skipped stitches. A size 80/12 or 90/14 is often suitable.
- Use a Walking Foot: A walking foot is highly recommended because it helps feed both the top and bottom layers of fabric through the machine evenly. This is crucial when sewing with materials like PUL where one layer might be slicker or stickier than the other, preventing stretching, puckering, and misalignment.
- Use Good Quality Polyester Thread: Polyester thread is strong and durable, making it suitable for projects requiring resilience, especially those involving moisture. A good quality thread prevents breakage during sewing and in the finished product.
- Use a Longer Stitch: A slightly longer stitch length (e.g., 3.0 mm or 3.5 mm) is often beneficial when sewing PUL. Shorter stitches put more holes closer together, potentially weakening the seam and reducing waterproofness. Longer stitches create fewer perforations along the seamline.
Summary of Key Sewing Practices for PUL
To simplify the process, here's a quick reference guide:
| Sewing Step | Recommended Method for PUL | Reason |
|---|---|---|
| Preparation | Skip prewashing | Maintains waterproof layer integrity |
| Patterning | Use pattern weights | Avoids damaging holes from pins |
| Joining | Use sewing clips | Prevents permanent holes in waterproofing |
| Needle Type | Ballpoint or Stretch Needle | Minimizes damage to fabric fibers & coating |
| Presser Foot | Walking Foot | Ensures even fabric feeding |
| Thread Type | Good Quality Polyester Thread | Durable and suitable for functional items |
| Stitch Length | Longer Stitch (3.0mm+) | Reduces perforations, strengthens seam |
| Ironing | Low heat, pressing cloth (if needed) | Prevents melting of polyurethane |
By implementing these techniques, you can effectively sew PUL fabric for various projects like wet bags, cloth diapers, rain gear, or bibs, ensuring both durability and functionality.
