Warp, Weft & Bias = Fabric Grain.
Most quilters that have come from a dressmaking background will be aware of fabric grain, how it can cause problems and how to manipulate it to advantage. Not all quilters I speak to are aware of what fabric grain is, so here’s a brief explanation that may be helpful.
If you take a square piece of woven fabric that has been cut parallel to the threads and stretch it in one direction and then the other direction, you will find that one direction has more stretch than the other. The direction that has the least stretch is known as the warp. These are the threads that run lengthwise along the fabric and are the base threads upon which the weaving is done. The other direction that has a little stretch is called the weft. They are the threads that run across the width of the fabric and are woven in and out of the warp threads to form the woven fabric. If you stretch the square diagonally from corner to corner you will find that it has a lot of stretch, this is known as the bias.
Understanding fabric grain means you can avoid issues with stretch when it is unwanted and use it to your advantage when needed. Below are just a few tips…
- When binding a quilt with straight sides always cut the binding strips on the straight grain (warp or weft), not on the bias. This will minimise wavy quilt edges.
- Cut binding strips on the bias when binding quilts that have curved corners or sides. The extra stretch of the bias will allow it to follow the curved edge without puckering.
- Generally cut patchwork pieces on the straight grain (warp or weft), unless fussy cutting is important to your design.
- Avoid stretching the bias edge when sewing triangles, diamonds etc. Never pull on them when machine sewing. Releasing the pressure foot a little can also help to avoid this.
- Cut strips on the bias for curved stems and vines in appliqué designs.
- When using the traditional needle-turn appliqué technique, unless fussy cutting, position the template on the fabric so as many curves are on the bias. This makes the seam allowance easier to needle-turn.
- Pre-washing fabrics before use is a good thing to do, not just to check for colour fastness but because of differential shrinkage between warp and weft threads. The amount of shrinkage for each fabric will differ too.