Welt Seam Method Single Layer with Twill Tape Covers

What is a welt seam method? What is “Single Layer with Twill Tape Covers” suppose to be?!

We’ll start from the very start by defining a welt seam. Basically it is a straight stitch that had both seam allowances ironed to one side. That is followed by two parallel lines of top stitching to secure the seam allowances down. This seam type is a fairly popular option in corset making. It is so popular there are at least 4 different variations  used for corset construction.

This tutorial right here will show you how to upgrade the “Welt Seam Method Strength Layer with Floating Lining” o be sure to check it out first!

You will do the upgrade by swapping the floating lining for twill tape. This allows for making lightweight single layer corsets that are also very neat looking on the inside.

The whole point of twill tape is to cover raw fabric edges of the seam allowances. Therefore, it doesn’t matter how strong or tightly woven your tape is. You will be placing your boning in-between the fabric pattern piece and it’s seam allowance. This makes it the boning channel strong and sturdy.

With that said, this method is limited by the allowing for making boning channels only on the connecting seam lines.

Seam allowance widths depend on the fabric thickens, number of layers as well as boning width and thickness. As always, making samples before starting your work on the corset, is always encouraged.

Tutorial sample is made using 200g cotton calico and 5mm wide spiral steel boning.

Happy sewing!

Free corset patterns

Aside from the instructional tutorial being available online, it can also be DOWNLOADED as a PDF file for offline viewing.

two pieces of fabric stitched together

Start by laying your pattern pieces right side on right side (or face on face).

Stitch them together with a plain straight stitch.

Seam allowances ironed to the side

With pieces connected, iron both seam allowance to one side. Either from center front to the center back or the other way around.

Pick one and stick with it. It doesn’t matter which one you pick, you just need to be consistent through out the corset.

Make sure you iron the seam allowances well. You don’t want crooked or creased boning channels on your corset.

Grading the seam allowances before closing the welt seam

Notice that the seam allowances are rather bulky at the moment.

Depending on the fabric thickens, this can easily result in the allowance edge showing, through the layers, on the face of the corset.

You need to grade seam allowances to prevent or minimize the edge of allowance from showing on the outside of the corset.

Grading of seam allowances is very simple.
You just need to shorten the seam allowances the top allowance and the fabric piece.

With just one seam allowance in between, simply cut its width in half.

With seam allowances graded, press and steam the again, just to make sure everything is flat and crisp.




Twill tape positioned over the seam allowance

You will use the twill tape to cover the raw edges of seam allowances.

This will prevent the fabric from fraying and will make the inside of a single layer corset look nicer, be smoother.

Tape should be a bit wider than the seam allowances to fully cover raw edges.

Iron and steam your tape before sewing it over the welt seam, it will be easier to handle it while sewing.

Twill tape stitched ower the seam allowances, creating two boning channels

You can pin or baste the tape over seam allowances or you can apply it as you sew it on.

Width of the seam allowance and tape depend on the width and thickness of chosen boning.

This method can be use for making single or double boned channels.

Outside look at the twill tape stitched ower the seam allowances, creating two boning channels

With channels finished, make sure you are pushing the boning in to the channel formed by the main fabric and the seam allowance

Regular twill tape isn’t strong on it’s own to hold bones securely so rely  on the strength layer.

Happy sewing!