13 Mar 2019 • • by Heather Lou

Sourcing Interfacing and Supplies for the Jasika Blazer

Supplies for tailoring a blazer // Closet Core Patterns

This week we're talking provisions for your Jasika Blazer, and after discussing fabric, it's time to move on to interfacing and supplies! This part might feel intimidating if you've never done any kind of tailoring before, but I promise everything is relatively easy to source.

First up, interfacing! Because Jasika is designed for speed tailoring methods, we'll be using fusible interfacings to build up the structure and shape of our jackets. The main benefit of this is obviously speed (hence the name!) Traditionally tailored jackets create structure with many layers of sew-in interfacing and tons of hand stitching, and while I have nothing but respect for these methods (I bow down to all bespoke tailors) it makes for a much more laborious and time-consuming project. If you get the taste for tailoring, learning those techniques would definitely be the next stage in your sewing journey. Here's what we'll be using instead.


The Jasika blazer calls for three types of interfacing, all of which *should* be available at a well-stocked fabric store. If not, we'll include lots of online sources in this post, or you can purchase one of our speed tailoring kits that includes all the interfacings you'll need in addition to sleeveheads, shoulder pads and twill tape.

  1. Weft Interfacing: This is knit like interfacing with threads running throughout that is stable on crosswise and lengthwise grain but stretches on the bias. It gives the drape/suppleness of a knit interfacing with more stability. It is what you will use for interfacing the body of the coat. It generally comes in white or black.
  2. Knit Interfacing: Drapeable, soft, lightweight. This is used on the lapel facing and top collar and the flexibility lets it drape nicely over collar and lapel break. It should stretch on crosswise grain (4way stretch works well too). I'm not too fussy about what you use here as long as it is stretchy and flexible.
  3. Horsehair Canvas: This type of interfacing is traditionally made from the mane of horses (no  horses are hurt!) but you can also find synthetic varieties. It is firm and supple interfacing we'll be using to create stability at the front shoulder. You only need a very small amount, about 1/4 yard.
  4. Cotton Twill Tape/Stay tape: This will be used to stabilize a few key seams and help us create a beautiful roll line at the lapel. Look for it in widths of 1/4" to 3/8". It should be preshrunk by soaking in warm water and pressed until dry. Similar to this. If you can't find you can try subbing in for cotton ribbon.
  5. Shoulder pads: These are necessary to create the proper shape and structure at the shoulder. We are suggesting pads with a thickness of 1/4" - 3/8" thick, but you can also use 1/2" if that is all you can find. Just note you *may* need to adjust the pitch or angle of the shoulder for a thicker pad. I prefer this professional style of shoulder pad (felt layered with batting and the kind we include in our kit) but these foam pads will also work. Please note you can also use our free shoulder pad pattern to make your own (pattern coming in a week or so, but it is included in our course now).
  6. Sleeveheads: These are critical - they help cushion the armscye seam and create a lovely shape at the shoulder. They can be hard to find commercially, so in a pinch use a 2" strip of lambswool or cotton quilt batting cut on the bias. Or use our free pattern to make one yourself (again pattern coming soon!) Sleeveheads are available on Amazon here.
  7. Lapel button: 1 x 3/4" (19mm). You can use a button with holes or a shank, your choice.
  8. Clear button: This will be used to protect your jacket on the other side of the lapel when you sew on your button.
  9. Two 1 x 15" strips of lightweight cutton or muslin (not shown). These will be used to reinforce the corners of your welt pockets.
  10. Sleeve buttons (optional): 6 x 5/8" (16mm). These are merely decorative so feel free to skip them if you want.
  11. Leather or suede elbow patches (optional): We have pre-cut elbow patches available in our shop or you can cut your own using the included pattern piece. If you use real or faux leather, you should use a leather needle to sew to the sleeve. You can find tips on sewing with leather here.
  12. Polyester thread: High quality only please! I recommend Gutermann or Mettler brands.
  13. Topstitching thread (optional): If you want to add a topstitched detail to your lapel, you can use topstitching thread or just use two spools to thread your needle twice.
  14. Silk thread: For basting and temporary construction, similar to this. This is very smooth thread that does not leave marks on fabric but regular poly thread can be used in a pinch.


To get good results tailoring, you need a few key tools. Most of these you probably also have, but you should definitely think about investing in a tailor's ham, seam roll and clapper or point presser if you don't already have it in your toolkit. I promise these are tools you will use again and again!

  1. Sewing machine: The average domestic sewing machine is all you need to sew a tailored blazer - no serger necessary!
  2. Quality iron with good steam: I recommend the Rowenta Focus or a gravity feed like the Silver Star.
  3. Dressmaking shears or rotary cutter: I like these scissors and this rotary cutter.
  4. Pinking shears: These are very important! They will help soften the line of interfacing on partially interfaced pieces so it doesn't show on the right side of the fabric. Something like this.
  5. Pattern weights or pins if you prefer to pin your pattern to fabric. These flat head pins are my favourite because they are easy to pull out while you're sewing.
  6. Sewing machine needles: Choose an appropriate weight for your fabric (I generally go with a 80/12 or 90/14 needle). You should have a finer needle like a 60/8 or 70/10 for your lining. If you are sewing leather elbow patches, you may want to use a leather needle.
  7. Marking tool like a Chaco liner or Tailor's chalk.
  8. Point turner: to help turn the lapel and collar like this.
  9. Hand sewing needles and a thimble: I like these Japanese needles. Running your thread through this wax and then pressing it between paper towels to remove excess wax helps prevent thread snarls. This leather thimble is the best.
  10. Wood clapper for crisp seams or an all in one clapper/point presser for pressing open the small seams around the collar and lapel. This is a vital tool; it is hard to get truly professional looking seams without using a wood clapper to help flatten and "lock" seams in place.
  11. Tailor's ham and seam roll. You can probably get by with just a tailor's ham but I find the seam roll invaluable for pressing open seams without the seam making an impression on the right side of the fabric.
  12. Press cloth: I prefer using silk organza because I can see through, but lightweight cotton or linen also works. You can find inexpensive silk organza at Dharma Trading Company.


Again, our kits include all the interfacing & supplies you need, but you can also find it at the following online stores. I had trouble finding European shops but if you know of more European tailoring supply sources please let me know!

So that's it! Later this week we'll be covering fitting and making a muslin. Any questions about tools and supplies?

Learn to Sew A Classic Blazer // Modern Speed Tailoring Course from Closet Core Patterns

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