Coat Series - Step 2: Set the Interfacing

The interfacing is, without a doubt, the most important part of an 18th century coat or waistcoat. It keeps everything where it is supposed to be and makes sure that your front panels stay erect and do not sag under the weight of fabric and buttons. At minimum, you will need to interface the front edges of your coats, but you should also interface the pocket flaps (and sleeve flaps if you are doing a mariner cuff). 

For your interfacing, you will need pre-made linen buckram, or you can make your own from cheap linen fabric. I make mine because it ends up being cheaper in the long run, but it does add a delay to your sewing process. I'll cover making buckram in another post.

Placing the Interfacing

Where interfacing is placed in your coat depends on the fabric that you are using:

For Linen, Worsted, Silk, or Cotton

If you are using a fabric that the edge will fray on i.e. linen, worsted, cotton, etc. your interfacing will be cut the match the edge of the garment and will be set back from the edge of the fashion fabric right tracing seam allowance line. I use 1/4 inch seam allowances, so my interfacing is 1/4 inch from the edge of the fabric. The key is that when you fold the fashion fabric back over the interfacing, the crease forms the finished edge of the panel.

For Wool Broadcloth

If you are using a fabric that will hold an edge i.e. wool broadcloth, the outside seam of your fashion fabric will not have any seam allowances and will be left raw. If you cut your interfacing piece to match the true edge of your garment, you risk that the interfacing will stick out once finished. You will need to trim about 1/4 inch off the outside edge of your interfacing piece, and place it 1/4 inch from the edge. You will lose a tiny bit of stiffness on the edge of your garment, but it will be made up for with the underhand stitch that you will run later to join the lining to your fashion fabric.

Securing the Interfacing

Before you can do any actual sewing, you need to do some pre-sewing to make sure that your interfacing does not shift and is sewn in flat so that your garment does not come out looking lumpy. This pre-sewing is called basting, and it is meant to keep everything in place. 

Basting is essentially a less stabby version of putting a ton of pins in your garment to keep everything from moving. The nice thing about basting is that it keeps everything in place perfectly without constantly stabbing you and it makes your garment very portable to work on because you don't have to constantly worry about where all the pins have gone. The bad thing is that it takes a while to do, and you will eventually pull it out.

Basting is a simple process. You are simply sewing a very spaced out running stitch down the length of your interfacing to secure it. You run your basting stitch though the fashion fabric and buckram for a few threads, then you space the next stitch about an inch or more apart. You want to use a thread that is light and that you can easily see.

I cannot stress this last part enough: to make sure that everything lays flat, do all bastings on a table keeping the garment as flat as possible. You will not realize it at the time, but the fabric is moving constantly if you try to baste with the garment in your hands. The result will be that your panel is lumpy and you have to start all over again.

To make sure that everything is secured in the right place, I pin the outside of the interfacing in place, then baste down the edge until everything is secure, and remove the pins.

Next, I turn the piece over so that I'm looking at the fashion fabric. I then do a series of bastings on the right side of the fashion fabric, moving across the interfacing to ensure that the outside of the garment is flat and that it is properly lays flat across the interfacing.

Finally, I turn back to the inside of the garment, and baste the inside edge in place. The final result looks something like the picture above.

I know this seems like a ton of work for nothing, but your garments will come out looking much better for it.

Sewing the Interfacing in Place

Now that you've done all this prep work, it's time to finally sew the interfacing in place. For linen, silk, worsted, or cotton: fold the outside edge over the interfacing and secure in place using a whip stitch. There is no need to fold over if you are using broadcloth; simply whip the outside edge of the interfacing in place. In either method try to avoid stitches coming through your fashion fabric.

To secure the inside edge, you will be using a zig-zag stitch, which is also called a herringbone stitch. Here is a video on how it's done. 

This fancy little stitch works much better than a whip stitch because it draws everything in tight and it will make sure that your interfacing does not move at all. This is a strange stitch because it moves backward. Your needle will be pointed in the opposite direction from the direction that you are sewing. You get no points for big stitches here, try to only catch a few threads for your zig zags. Historic garments show about four of these per inch.

When doing this stitch, one point of the zig-zag goes through the interfacing only, and the other side goes through the fashion fabric only. Make sure that you only catch a few threads on the fashion fabric to show as little thread as possible. I keep my outsize stitch so that it nearly touches the interfacing, and the inside stitch is about 1/4 inch into the buckram. 

Extra Interfacing for Coats

M. de Garsault and Diderot talk about putting an extra layer of interfacing running the length of the buttons on coats. Although, some see this as an optional step, I see it as a must to provide extra stiffness behind the weight of the buttons.

The period documentation calls for using "stay tape," which I think may be a mis-translation from French, because I could not imagine using 1 1/2 inch or wider linen tape to make a interfacing strip for my buttons. I also don't know where to find linen tape that wide. I personally have not seen linen tape used to back buttons in period garments, so if you've seen it: send me a picture!

Securing the button backing is much easier than the large interfacing. You do not need to do the whole whipping and zig-zagging to put in in place because there are other stitches coming later that will overly secure it.

To secure the button backing, I simply do a basting stitch using a back stitch at the securing points instead of a running stitch along each edge to make sure nothing moves. There is not need to go through the fashion fabric at all. Simply run the back stitch through both layers of buckram and call it a day.

Ending

Your interfacing is finally secure. Huzzah! I know that it's tempting to pull out all the bastings right now, but don't do it. You put all that hard work into it, and it's giving your garment a little extra security.