In outdoor clothing making, interfacings are used only for small garment pieces such as flaps, collars, waistbands, pocket flaps and so on.
Interfacings support and stabilize these garment pieces.
Interfacings are mainly separated into iron-on and sew-on interfacings. The type of interfacing depends on the fabric. Generally iron-on interfacings should be your first choice. If the iron-on interfacing does not stick, consider the sew-on interfacing. Eitherway, the interfacing should not interfere with the flow of the fabric and the fabric should remain soft after ironing.
The image shows my favourite interfacings for outdoor fabrics.
Iron-on interfacings have glue on one or both sides. The glue is activated through heat from an iron or iron press. The type of glue used also plays a role in the overall outcome, as some glues make certain fabrics stiff and hard.
There are many different kinds of iron-on interfacing on the market: woven-cotton, fleece (vlies), jersey, woven-wool and many others. Each comes in a lighter or heavier form. Some have a 2-way stretch while others have a 4-way stretch. Then they are some with no stretch at all. And then they are some which have an integrated support thread.
Most fleece (vlies) interfacings stretch sideways but not lengthwise. They are part of the 2-way stretch interfacing. Most jersey interfacings belong to the 4-way family.
Different factors should be considered when choosing the interfacing for your garment piece:
- Should the fabric pieces still stretch or not.
- Should the interfacing help with the sewing of the stretchy fabric.
- Should the interfacing just stick to the fabric piece (glue on one side) or
- Should it stick two fabric pieces together (glue on both sides).
- The type of glue used on the interfacing: the glue should not come through to the outerfabric side.
- Should the outer fabric remain soft or be stiff.
- Can I use for example a different fabric to come to the same outcome, for example when stiffening the brim for a hood.
I personally stay away from woven cotton interfacings and interfacings with glue on both sides. In my opinion, both types interfere with the natural flow of the fabric and make them stiff and hard.
Direction of Interfacings
Small garment pieces, such as flaps, welts, waistband, collars should not stretch lengthwise. The grain line/selvage is not necessarily the lengthwise direction of the pattern piece, see image.
The stretch of the interfacing influences the amount the garment piece will stretch after applying.
Two-way and 4-way stretch fabrics are tricky. Applying interfacing helps with the sewing at certain pieces, such as pockets, collars, flaps, waistband …. During sewing, make sure you have the non-stretch (less stretch) fabric/zipper piece facing you!
Make sure that you cut the small garment pieces, which require interfacing, with as little stretch as possible in the first place. It helps to cut the interfacing the same way.
In conclusion, to make your sewing life easier, watch out which way you cut the interfacing before you apply it as it influences the stretch in the garment pieces.
How to apply iron-on interfacings
Always test the interfacing on a small fabric piece first, 20 x 20 cm (8 x 8") piece.
See how it sticks and if it gives the right amount of support.
Most fabrics shrink during the iron process. To avoid a too small garment piece afterwards, always pre-cut the fabric for these garment pieces. The fabric pieces should match the general outline of the garment piece. Cut the fabric piece slightly bigger.
- The interfacing is cut a bit smaller than these pre-cut pieces.
- Set your iron on 2 dots.
- Place the glue side of the interfacing onto the inner fabric side.
- Set the iron from spot to spot and count each time 5 − 6 seconds. Avoid pushing the iron over the interfacing. Repeat for each spot 2-3 times.
- Before you continue to work with the pieces, let it cool down for 15 − 20 minutes, so the glue can set.
Note: Some iron-on interfacings require a wet cloth or steam to activate the glue properly. Follow the instructions given in the fabric store.
Sew-on interfacings come in lighter to heavier forms with a different volume. Most sew-on interfacings are part of the 2-way family. They are sewn or basted onto the garment piece.
Sometimes it is not possible to use iron-on interfacings on certain fabrics as it simply does not stick or it comes right off again. In these cases use the sew-on interfacing. Sew on interfacings have no inner or outer side.
How to apply sew-on interfacing
- Cut out the pattern piece from the fabric, seam allowance included.
- Cut out the piece again from the sew-on interfacing, seam allowance included.
- Place and pin the sew-on interfacing onto the inner fabric side of the garment piece.
- Use the basting stitch or a long stitch length on your sewing machine.
- Sew right next to the seam, 0.2 - 0.3 cm (0.08 - 0.12") inside the seam allowance.
- Do not back stitch.
- Iron the piece after sewing from the outer fabric side.