Just as important as knowing how to cut your pattern and stitching the seams together is the need to clean finish all the raw edges of a garment. Why do we need to do this? Well because most fabric weave edges fray, which causes threads to come undone at the edge affecting the durability of a seam, as well as the “cleanliness” of a clothing item. Nobody wants to walk around with small pieces of thread hanging everywhere, right? Luckily, there is a variety of different ways you can finish the raw edges of your seams, and some of the most common ones are done directly with your sewing machine. Bellow, we are going to walk you through 4 most common methods to clean-finish seams on the inside of the garment step by step with picture demonstrations. Let’s get started:
1. Serging or Zig Zag (on a home sewing machine)
1. Serging or Zig Zag (on a home sewing machine)
This is the most common seam finishing and is done directly on the machine. For the serging stitch, you will need a serger (or overlock machine). If you are a more seasoned dressmaker, we highly recommend a serger, because it will become your go-to for finishing all raw fabric edges in a professional, clean manner. If you are just beginning to learn how to sew, you can substitute the serging stitch for a Zig Zag stitch on your home sewing machine.
Step 1: Once your seam is stitched together, run a serging or zig zag stitch along the edge of the raw fabric.
Step 2: Iron excess seam allowance towards the back of the clothing item you are sewing. The easiest way is to iron the seam on the face of the garment.
2. French Seam
This is a more expensive seam finish and is most commonly found on higher priced silk blouses and dresses, and a variety of different chiffon fabrics. It is not a seam you will find in outerwear or heavier pieces- it is a very dainty finish that requires a thin, delicate fabric. While you should learn how to do the french seam on a regular sewing machine, there are new sewing machines on the industrial level that can sew a french seam in a single step, but you don’t have to worry about that unless you are an apparel manufacturer!
So why should you use this as opposed to a regular serged seam? Well, it will be a more durable, clean finish that doesn’t run the risk of bunching up under the rough stitch of the serger. If you are working with 100% silk fabrics that are delicate, a serging or zig zag finish can risk catching some of the threads in the weave and bulking up the seam on the outside (if the needle is not sharp and thin enough). A french seam is also a more durable, high quality option for thinner fabrics.
Assuming your seam allowance is ½”
Step 1: Align the edges of the fabric at the corresponding seam with the back side of the fabric touching. The face of the fabric should be on the outside. Sew at ¼” seam allowance.
Note: In the fabric sample bellow, the darker side of the print is the back of the fabric.
Step 2: Iron excess to one side, then fold and iron seam to enclose the raw edges of the fabric as shown in the image bellow. Pin to reinforce this fold.
Step 3: Sew along the fold at ¼" seam allowance again. You will notice that the fold will remain on the inside and the outside will be a clean finished seam. This finish will ensure raw edges are enclosed and a clean finish, both on the inside and outside of the garment, is achieved.
Step 4: Iron the fold towards the back of the garment. Iron on the face side of the seam as shown bellow.
3. Flat Fell
A very common finish used with denim fabric. You will see the flat fell seam used on jeans, denim jackets, casual jackets and blazers that have a lot of top stitching. This is also a seam that requires enclosure of the raw edges, but as opposed to the french seam, it is a lot more heavy-duty and used with thicker wovens that are easy. So how do you sew a flat fell seam? We’ll show you!
Our edges have ½” seam allowance.
Step 1: Stitch the seams together at ½” seam allowance making sure the face of both fabric pieces are touching. (The back-side of the fabric should be on the outside). Once done stitching, iron the seam allowance open as shown below- This will facilitate the next few steps.
Step 2: Trim one side of the seam allowance excess at a ¼” (or in half).
Step 3: Fold the larger, untrimmed seam allowance at a ¼” in, and iron down this fold. Overlap to enclose the trimmed raw edge. Iron again and pin to secure the overlapped fold in place.
Step 4: Stitch close to the edge of the fold, using it as a guide. Iron the seam on the face of the garment for a clean, professional look.
4. Using Binding: Bound Seam
You will find this seam finish on outerwear styles like unlined jackets, trench coats and heavier cardigans and vests. Back in the day, bound seam finishes were very commonly seen in dress skirts/pants and business suits. Today unfortunately, this is a more costly finish so it is only used when necessary on heavier pieces. You can purchase a presser foot to sew a bound seam using a pre-cut strip of fabric in a single step on your sewing machine, but we won't recommend that until you feel comfortable sewing one the long way- using a regular straight stitch presser foot. You can make your own binding by cutting a strip of fabric on bias and triple folding it. As a sewing beginner however, we recommend buying pre-cut, pre-folded binding from your local fabric store. It comes in a variety of different widths from ¼” to ¾”. For light to medium fabrics with ½” seam allowances we recommend using ¼” binding as a finish. For thicker, bulkier fabrics you a 1/2" wide double folded binding works best.
In the demo bellow, we are working with a ½” seam allowance again.
Step 1: Stitch the seam together with the face of the fabric touching at ½” seam allowance.
Step 2: Unfold the binding and align one of its edges exactly to the raw edge of the fabric. Pin it horizontally to keep the fabric and binding together. Stitch at ¼” on top of the binding’s fold line as shown below.
Step 3: Close the binding’s fold over the raw edges to enclose it. You can iron this fold down to make it more stable for sewing. Put a few pins through to makes sure the fold doesn’t move.
Step 4: On the side where the binding’s fold is open and not yet stitched to the fabric, sew a straight stitch on top of the binding as close to the edge of the fold-line as you can. Use the fold's edge as a guide while sewing.
Step 5: Iron down the seam with the seam allowance pointing towards the back. Iron on the face side of the seam.
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