This post isn’t anything dark and sinister but it could make or break your sewing project! We often take for granted how our sewn garments and accessories are constructed and apart from the actual fabric, we often look past what is underneath the fabric (or between the layers) which give us the look, feel and body of our sewn item. This is where interfacing comes into play.

Now before I begin, just a warning, this will be a bit of a technical write up (and a bit long, but it is necessary to get into the details).

INTRODUCTION TO INTERFACING

What is interfacing & why is it important?

Wikipedia gives a definition which is easy to understand. It states that,

“Interfacing is a textile used on the unseen or “wrong” side of fabrics to make an area of a garment more rigid. Interfacings can be used to:

-stiffen or add body to fabric, such as the interfacing used in shirt collars

-strengthen a certain area of the fabric, for instance where buttonholes will be sewn

-keep fabrics from stretching out of shape, particularly knit fabrics

Interfacings come in a variety of weights and stiffnesses to suit different purposes. They are also available in different colours, although typically interfacing is white. Generally, the heavier weight a fabric is, the heavier weight an interfacing it will use. Interfacing is sold at fabric stores by the yard or metre from bolts, similar to cutting fabric. Sewing patterns specify if interfacing is needed, the weight of interfacing that is required, and the amount.”

In relation to craft sewing and bag making, it is as important as the fabric, as without interfacing all our crafts & bags would look pretty much like a collapsed pile of fabric. Without the underlying interfacing, we would have floppy pouches, shapeless bags and fastenings which would not survive without the fabric being reinforced & strengthened with interfacing.

You may have heard some people call it interlining. Traditionalists will say interfacing is used to support ‘facings’ such as supporting a neckline so it won’t droop but help the fabric lie flat against the body, whereas interlining is described as the textile used between the outer fabric and lining fabric for purposes like changing the drape of a dress.

The terminology seems interchangeable nowadays. The function of both are pretty much similar, that is to stabilise, strengthen and give a desired shape to the main fabric.  From here, I will use the term interfacing. So imagine if you would like to sew a strap of a tote bag with fabric. If the fabric you are using is too soft, thin and it crumples too much, you may want to add a light weight to medium weight interfacing to reinforce the fabric as it will be taking in some stress from the weight of the contents in the bag but it can still be somewhat soft to the touch when it sits on your shoulder. Others may prefer a stiffer strap and so will opt for a thicker and firm interfacing to fuse in-between the fabric used for the straps.

Types of interfacing.

There are categories of interfacing to choose from.

• Woven vs. non-woven interfacing

Woven is just that, it’s woven. Close up, you will be able to see the criss cross weave and so, you would cut with the grain line in mind just like cutting fabric. On the other hand, non-woven interfacing can have the texture and look a bit like tissue paper or recycled paper. There is no grain line, and so you can lay out  and cut out your pattern piece in any direction.

Non-woven interfacings can tear more easily because of it’s nature and if there is a lot of rubbing against it, it may start to breakdown a lot faster. Non-woven will generally be cheaper than woven but woven interfacing will look and feel more like a fabric and because of that, I personally like to use woven interfacing for my projects.

• Fusible vs sew-in interfacing

Sew-in (non-fusible) interfacing is known more for garment sewing. A method of attaching the interfacing is to baste the interfacing in the seam allowance. For heavier sew-in interfacing, some people use the catch stitching method. A couple of reasons for using sew-in interfacing are when your fabric is too delicate and you would not want to alter the drape of the fabric by fusing it to interfacing or if the fabric is heat sensitive and hence, it cannot take the heat needed to fuse the interfacing without damaging the delicate fabric.

Fusible interfacing is also used for garments but is the popular choice for craft and bag making. One side of the interfacing has fabric glue attached to it. The glue comes in different forms. Sometimes the glue lies very flat against the interfacing or can be raised and rough to the touch. Some would look like dots of glue while other glues just look like a shiny surface. The interfacing is applied to the fabric when the “glue” side is fused to the back (wrong side) of the fabric by the heat from an iron. Once applied, fusible interfacing will change the weight, stiffness and body of the fabric. Sometimes I am surprised how the fabric looks after the interfacing is fused on. When you have chosen an expensive fabric to work or it is an important project, do test the interfacing on a bit of the exact fabric so you know exactly how it looks and moves after the application.

There is no “best” interfacing. It is the question of what is the most suitable interfacing for the requirements of your project. To be able to make the best choice, first ask yourself what is the finishing that you want in your end product.

How to apply fusible interfacing.

Ironing on fusible interfacing should be easy, yes? Yes, it should be but one has to take into account the temperature of the iron, the pressure placed on the interfacing from the iron and the length of time to fuse the interfacing. Do note as well, everyone uses different models/brands of irons, so there can be a few variables when it comes to applying interfacing. It comes down to the method of application.

The common procedure is take your fabric with the good side facing down the ironing board. Then place your interfacing, glue side down onto the wrong side of the fabric. At this point, you can place a press cloth over the interfacing. Ensure you set your iron temperature suitable for your chosen interfacing. This is how I apply it. Start ironing/pressing from the centre of the fabric, holding it for the time needed and then lift the iron and place it down again next to the fused area of the fabric (with some overlap) and continue to work your way outwards until the whole cut out sheet of interfacing has fused onto your fabric. So it is a lift up, place down (or stamping action), count however many seconds and repeat. Never push, pull or slide the iron over the interfacing because you may shift the interfacing against the fabric which will then cause it to bubble, warp and disfigure your fabric and interfacing. Do flip it over and give it an overall press on the good side of the fabric before leaving it aside to cool down.

As for the temperature, a good starting point is setting your iron on the 2nd notch/setting no.2. It might be indicated as 2 dots on your setting dial (I can only speak for the irons sold locally in Singapore). This setting will sometimes be accompanied by the word SILK or WOOL. The setting for both silk and wool is around 148°C/300°F. I would use this temperature setting for the lighter interfacings and have gone up to the halfway mark between the 2 dot/notch to 3 dot/notch cotton setting. Again, this depends on the thickness of the interfacing, the glue, the fabric, the pressure you exert when fusing and the length of time you fuse. Timing could start from a few seconds. I have found, the heavier the interfacing, the longer you can fuse the interfacing to ensure the glue has fused both the interfacing and fabric properly.

As I write this, I realise there’s so much more to it that it might be easier for you all to digest if I make it as bullet points! ( ahem…long bullet points)

• • If you don’t use a pressing cloth…

    Do ensure that the interfacing is the same size or smaller than the fabric. Otherwise, you will be fusing the excess parts of the interfacing onto your ironing board which will leave a glue residue on your board. Depending how bad it is, you might get away with scraping it off or you may have to wash it off with a damp cloth and soap. If you turn your fabric over for a last press (on the right side of the fabric), the glue on the exposed parts of the interfacing may transfer onto your ironing sole plate in which case you will definitely have to stop to clean the sole plate as the glue could transfer onto your next piece of ironing and also clog up the holes in the sole plate. I personally use “RAYEN, Iron Cleaning” which I buy at NTUC Fairprice. I have tried other iron plate cleaners but some give off awful fumes. This one is easy to use, effective and dosen’t give off a chemical smell. It actually has a light lemon scent.

  • Do iron out all the creases in your fabric before fusing the interfacing.

    Do not skip this step. There’s no killing 2 birds with one stone here. Trust me, your creases will not be ironed out with the fusing of the interfacing. Cut away any stray thread as you won’t want the thread to be fused in between the interfacing and fabric. It will show up on the right side of the fabric as a squiggly fine bump.

  • If it’s your first time using the interfacing…

    Test it out! There’s nothing worse than to ruin the fabric and time taken in the preparation, if you end up scorching the interfacing or having pockets of bubbles between the fabric and interfacing. Test the interfacing using a scrap of the fabric, or similar fabric to test out how hot your iron needs to be and how long you should press down for. The thinner the interfacing, generally the shorter the time. The more plasticky your interfacing feels, try using a lower heat and shorter time and test whether the interfacing has fused properly and from there you can gauge the temperature, pressure and time needed.

  • Steam or dry iron?

    I have read some people use the steam mode to fuse interfacing or using a damp pressing cloth over the interfacing but this all depends on the brand of interfacing. Always refer to the instructions that come with the interfacing or check with the staff. So far, the interfacing I have used does not need any steam. So far, I have only needed a dry iron. Please take note, it is not that the case of the hotter the better, because there will be an optimal point (after which is the point of no return!) than you will go over board with the temperature and the glue can melt and join/clump up to other sections of the glue, leaving air pockets where there is no more glue. We do not want that. No. We do not want to be crying over our ironing board lest our kids think we’ve gone mad.

  • How much pressure to apply?

    This one is difficult to measure. Most of us don’t have a commercial grade iron press machine which we can lock in the temperature, time and pressure. This is why it’s important to check after your first “fuse” that the interfacing has bonded well. Try to lift up the corners of the interfacing to test out whether the heat & length of time has been sufficient to completely fuse the interfacing. From my experience, the thicker interfacing can take a bit more pressure and those interfacings which are tightly woven and have a flat and shiny glue surface need a bit more pressure.

  • What if your interfacing has been ruined?

    In this case, take a deep breath and quickly go over the interfacing with your iron on a medium heat and with lighting speed and nimble fingers, peel off the interfacing with even force while holding onto the fabric so that your woven fabric dosen’t go out of shape. You may need to repeat this a couple times, depending how large your interfacing is, so you will be peeling off the interfacing in sections. This is not something I recommend, but yes, unfortunately I say this with experience and hence, can “guide” you on this. Ah-hem. At this point, if you think your fabric looks salvageable and if most, if not all of the glue has been lifted off the back of the fabric, you can press the fabric back into shape (might need a bit of steam action here) before fusing on a new interfacing. Or to be doubly sure, you could gently hand wash the fabric in case you fear there are traces of glue on the wrong side but at the end of the day, you need to make a judgement call on how much effort you want to put in salvaging the fabric.

  • Always let your fused fabric cool down on a flat surface.

    I learnt early on that if your interfacing is still warm, it can take on a curved shape if you have draped it over an item. Once it’s cooled flat, then you can handle it without it warping.

  I hope this post was helpful. It does takes time and experience to gain a better understanding of what works well with your projects but once you are more confident handing interfacings, you will gain a lot of satisfaction that your handmade item turned out exactly the way you imagined it to be!