Interfacing is so important for Opium that it gets its own cutting layout in the booklet, and several steps in the instructions are dedicated solely to preparing the pieces. It is absolutely critical not to skip these steps: without interfacing, your coat would be completely slouchy and shapeless. It would be too bad to spend so much time on a garment only to be disappointed with the end result!
With Opium, we wanted to design a coat that would be accessible to outerwear newbies. To do so, we swapped traditional tailoring techniques, which are mainly done through handstitching, for modern techniques using iron-on interfacing. The latter serves several roles in the construction of the coat:
Just as with any sewing project, it is important to pick an interfacing that matches the weight of your main fabric. Here, you’ll need an interfacing for midweight fabrics for coats and jackets. You’ll get the best results with a woven interfacing instead of a non-woven. Pellon SF101 Shape-Flex or Vlieseline/Vilene G740 would be great for instance.
For an even more professional result, you can also use weft interfacing, such as Pellon 860F Ultra Weft or Vlieseline/Vilene H410. This is a woven interfacing that includes stronger threads running along the grainline, which add even more stability. Be particularly careful to respect the grainline when you cut this type of interfacing, including for the hem reinforcements!
Iron-on seam tape is used to reinforce the roll line of the lapel and the raglan seams, which are in the bias, so that they don’t stretch over time due to the weight of the coat. It also helps the lapel roll properly! By stretching the tape slightly while applying it, you’re contracting the fabric a little, which helps and maintains the roll: this is equivalent to the traditional tailoring technique which uses regular stay tape, but without all the handsewing 😉
You can find ready-made seam tape online or in stores from brands like Dritz or Collins, under the names fusible stay tape or seam tape. In Europe, Vlieseline/Vilene offers several types of tape that work for Opium: their seam tape, which is a simple interfacing tape, and their bias tape, which has a chainstitch running down the middle for more support.
You can also make it youself, which is just as easy and often much cheaper! To do so, simply cut 3/4” wide strips along the straight grain in your interfacing (the same one you’re using for the coat). Measure the length of the lapel fold line and the length of the raglan seams to know how much tape you’ll need.
Camille, November 6 2018
Thank you for all the info!
It’s not a problem that your tape is 1 cm wide, you can simple fuse it on the seam line (0.5 cm on each side). If you tape stretches enough to follow the curve you can do that, otherwise you can clip it as recommended in the instructions.
Barbara Turvey, November 9 2018
I’ve made the coat and I’m very pleased with it. Two points though. The welt pockets were extremely stressful as the amount of layers needed to be sewn at one time through a domestic machine is huge, and these are key to a professional finish. I found the lining didn’t fit as well as I would have liked, but with much tweaking it’s OK now.generally, the pattern went together well and I’m looking forward to wearing it in London next week when I meet one of my daughters for lunch!
Camille, November 9 2018
We’re really glad you like your coat, thank you for your feedback!
Crystal Rice, November 13 2018
I am preparing to cut my Opium coat today, and am considering using a fusible hair canvas to interface the lapel and collar. Do you think that might be too stiff? Should I use my medium weft interfacing instead?
Crystal Rice, November 14 2018
Well, I decided to stick with the weft, as my wool is pretty soft. I started to worry it would be too stiff with hair canvas!
Camille, November 16 2018
I think you did well! Medium-weight weft interfacing should be perfect.
Jennifer Sandoval, November 5 2018
I was planning on adding a larger seam allowance to the raglan sleeves and back to adjust for my broad shoulders. I have fusible bias seam tape that’s just 1cm wide; will this work, even though my seam allowance is much bigger?
Wear should I fuse it? Near my stitch line or in the seam allowance only? Would I still stretch the tape if it’s bias?
For the USA readers, Mood has a fabulous selection of fusibles and they have weft in different colors and weights. Vogue Fabrics and sometimes Amazon has bias fusible tape. I usually use the 3/4″ fusible knit tape for seams, but it’s easily made yourself.
No, I do not work for either company, promote them, nor get any kickbacks. I think Mood is rude, but their selection for wool and fusibles is unbeatable.