You use bias tape on seams primarily to finish the raw edges of the seam allowance, preventing fraying and providing a clean, professional look, especially in unlined garments.
Using bias tape to finish seam allowances, often called a "Hong Kong finish" when using a single-fold strip, is a durable and attractive technique. This method prevents fabric edges from unraveling and adds a touch of polished detail to the inside of your garment.
Why Finish Seams with Bias Tape?
Finishing seam allowances with bias tape offers several benefits:
- Prevents Fraying: Fabrics, especially those that fray easily, are secured.
- Durability: Adds strength and longevity to the seam edges.
- Clean Finish: Provides a neat, professional appearance to the inside of the garment.
- Adds Colour/Interest: Bias tape can be a contrasting colour for a decorative touch.
Steps for Using Bias Tape on Seam Allowances
Here's a breakdown of how to apply bias tape to finish your seam allowances:
1. Prepare Your Seam Allowance
Sew your seam as usual and press the seam allowance open or to one side, depending on your pattern instructions and desired finish. If pressing open, you will finish each raw edge separately. If pressing to one side, you can finish both raw edges together (though finishing separately is more common for a flat finish).
2. Prepare Your Bias Tape
You can use pre-packaged bias tape or make your own strips cut on the bias (a 45-degree angle to the selvage). Cut your bias strips about 1" to 1.5" wide. You'll need enough length to cover the raw edge(s) of your seam allowance.
3. Attach Bias Strip to Seam Allowance
This is the critical first sewing step. Keeping the garment out of the way of the needle (it helps to place the garment to the left, keeping your seam allowance / bias strip to the right), sew the bias strip to that seam allowance with a 1/4” seam. As the reference states, you should be sewing through just TWO LAYERS of fabric – one layer of your seam allowance and one layer of your bias strip.
- Align the raw edge of the bias strip with the raw edge of the seam allowance.
- Ensure the right side of the bias strip is against the wrong side of the seam allowance.
- Sew accurately along the edge at a 1/4" seam allowance.
4. Press the Bias Strip Away
Press the newly attached bias strip away from the seam allowance. This creates a crisp edge for the next step.
5. Wrap the Bias Tape
Now, wrap the bias tape around the raw edge of the seam allowance towards the wrong side. The fold of the bias tape should enclose the raw edge completely.
6. Stitch the Bias Tape in Place
Stitch the bias tape down from the right side of the seam allowance, stitching in the "ditch" or very close to the edge of the bias tape. You can also stitch from the wrong side, aiming to catch the folded edge underneath. This final stitch secures the bias tape, creating a clean, finished edge on your seam allowance.
Materials Needed
| Item | Description |
|---|---|
| Sewing Machine | With a standard presser foot |
| Bias Tape | Sufficient length, approximately 1" to 1.5" wide |
| Thread | Matching or coordinating colour |
| Scissors | Fabric and thread scissors |
| Iron | For pressing |
| Pins | To secure bias tape (optional but helpful) |
Using bias tape on seam allowances is a simple yet effective way to elevate the finish of your handmade garments. It's particularly useful for fabrics that fray or for projects where the inside finish will be visible.
