Blocking Fabric: Getting Fabric on Grain
Last week, we discussed how to determine whether a piece of woven fabric is on grain. That’s an important first step in sewing, as fabric must be on grain for projects to hang straight and maintain their shape. Fabric is on grain when the lengthwise threads run at perfect right angles to the crosswise threads throughout the run of the fabric. When folded in half lengthwise and with both the lengthwise and crosswise edges pinned together, the fabric is on grain when it lies flat at the fold line.
But, sometimes that is not the case. It is not uncommon for fabric to be off grain, either just a little or a lot. Whether you paid an arm and a leg for that piece of fabric, or picked it up at a deep discount, it happens. And, its easy to understand why. Fabric is typically manufactured on huge round bolts. For distribution purposes, the finished yardage is then folded in half, lengthwise, and rolled onto those rectangular cardboard “bolts” you see lining the aisles of fabric retailers. Through that process fabrics can shift, which sometimes renders the fabric off grain. Sometimes even gravity can put fabric off grain when bolts displayed in stores stand upright for extended periods of time.
For most fabrics, getting them back on grain is possible and requires nothing more than pressing the fabric back into grain. When off grain by a lot, a process called fabric blocking may be in order that will quickly and easily “pop” the fabric back on grain.
Pressing the fabric back on grain is the easiest solution. Here’s how to do it:
1. Fold the fabric in half with the wrong sides out (right sides together).
2. Pin the fabric together at 5-inch increments along the selvage and crosswise edges.
3. Using a combination of steam as well as heat, press the fabric toward the direction that will move the threads on grain.
4. Sometimes wetting the fabric and then pressing while still damp may be needed to reshape the fabric.
5. Be sure to keep the crosswise and lengthwise edges at right angles while pressing.
6. Pinning the fabric onto the ironing board will hold it in place while pressing.
7. This process works best on cotton and wool fabrics.
How to block fabric
When fabric is considerably off grain, the best solution to popping it back on grain is to perform a technique called blocking. This technique calls for pulling or stretching the fabric from opposite corners in the direction required to move the fabric back on grain. This may require several attempts, but with some patience, it will do the trick nicely. You know it has worked when the fold line no longer ripples, and instead lies flat with the selvage and crosswise threads at perfect right angles to one another.
Some fabrics are near impossible to get back on grain. Woven fabrics with stretch are particularly challenging. If it can’t be straightened, I typically return the fabric rather than making a garment that will be perpetually off grain. Prints are sometimes printed off grain, so while the fabric may be on grain the print will not. In those cases, lay out the pattern pieces to line up with the print and not with the fabric gain. Or, do what I do — return the fabric.