Underbust Variations

This secttion shows how to create two variations of the Underbust Corset. The first is a double layer of fabric that combines fashion fabric with a lining. The second variation is a single layer corset with the pattern reduced for tight lacing.

These instructions use the patterns created in The Underbust Pattern and refer to the techniques described in Construction Basics.

Double Layer Corset

Compression Corset

To create these corsets, you will need the following materials. The use of white steel boning is described but you may substitute 1/4" spiral steel boning.

Preparing the Pattern & Fabric
for a Double Layer Underbust Corset

The first step is to create a paper copy of the Underbust sloper pattern. Do not copy the seam allowances from the sloper, only the sewing lines.

1. Use pattern paper to copy the Underbust Corset sloper. Do not include the seam allowances.
2. If precut boning is to be used, adjust the bottom of the corset as required to accommodate the available lengths. The boning should be 1/2" (12 mm) shorter than the distance between the edge bindings. For this example, the boning should be 1-1/2" (38 mm) shorter than the height of the corset at each boning location.
3. Shorten the width of the center back panel for the lacing by 1" (24 mm).
4. On the sides of all pattern pieces, draw 1/2" (12 mm) seam allowances.
5. Add sewing notches and label the pattern pieces clearly.
6. Cut two of each pattern from the fashion fabric for a left and right side. Be sure to cut the side back panel on the bias to allow for stretch.
7. Cut two of the center front, side front, and center back patterns from the lining fabric.
8. Cut two each of the side back panel from powernet.
9. Cut four each of the center back panel from fusible interlining.

Corset Pattern

Insert the Opening Busk

Locating the opening busk at center front allows a wearer to put a corset on and take it off without the assistance of another person. The busk is sewn between the fashion fabric and the lining of the center front panels.

In the video below, temporary chalk marks are applied to the wrong side of the fabric to clarify the busk is being inserted correctly in the corset. In this example, the knob half of the busk is inserted on the left side of the body. Left handed people may prefer the knobs on the right side.

For videos of the steps below, see Construction Basics Inserting the Opening Busk.

1. Pin the left fashion fabric to the left lining, right sides together, then sew the center front seam.
2. Press the seam allowance open.
3. Place the fashion fabric over the knob side of the busk, aligning the edge of the busk to the center front seam. The top of the busk should be 1/4" (6 mm) below the edging allowance.
4. Start at the top and use an awl to open a hole in the fashion fabric for the first knob to work its way through.
5. Continue down the busk, opening holes for each of the knobs.
6. Fold the fabric so the seam allowance is under the busk and the fashion fabric and lining are correctly aligned at the top, wrong sides together.
7. Use a zipper foot to sew the busk between the fashion fabric and the lining.
8. Pin the right panel of the fashion fabric to the lining, right sides together.
9. Place the right panel next to the left, aligning the top and bottom edges.
10. Place the loop side of the busk on top of the right panel and mark where the loops will fall along the center front seam.
11. Sew the center front seam leaving gaps for the loops.
12. Slip the loop side of the busk through the gaps in the seam allowances.
13. Fold the fabric so the fashion fabric and lining are correctly aligned at the top, wrong sides together.
14. Use a zipper foot to sew the busk between the fashion fabric and the lining.
15. Before proceeding with the remainder of the corset construction process, verify that the busk will close properly.

Sewing the Corset Body

Once the center front panels have been prepared with the opening busk, the body of the corset can be sewn. For double layer corsets, the grommets are installed after both sides of the garment's body have been sewn together.

Sewing a Double Layer Corset

1. Pin the corset's, right sides together, then sew along each seam location.
2. Press open the seams, then trim the two sides of the seam allowances to different widths. If one side is 1/2" (12 mm), the second side should be 3/8" (9 mm). This is referred to as grading the seam allowances.
3. Press the seam allowances of the fashion fabric toward the side of the corset. The seam allowances should not be pressed open.
4. To minimize the finished corset's bulk, press the lining seam allowances in the opposite direction from the fashion fabric's seam allowances.
5. It is a good idea to hand or machine baste the seam allowances in place.
6. Add the grommets to the center back panels as described in Construction Basics Inserting the Opening Busk
7. Turn the corset right side out and pin or baste the fashion fabric seams so they are directly on top of the lining seams.

Important Note: before proceeding further, verify the corset's fit for this combination of fabric.

Pinned Corset Body

Adding the Boning

Boning can now be added to the corset. Rather than using casing, fashion fabric is sewn to the lining to create channels for the boning. For this example, solid white steel 1/4" (6 mm) boning is used at the grommet location. The video below shows how to cut this type of boning. The specifications for protecting the ends of the boning will vary depending on the specific product you are using.

Cutting White Steel Boning

1. Determine the length for each piece of boning.
2. Cut the boning to length.
3. Trim the end of any sharp corners, then file it smooth.
4. Prepare the protective coating as directed for the product being used.
5. Take about 5 seconds to slowly lower the cut end of the boning into the coating solution.
6. Take another 5 seconds to slowly remove the boning.
7. Allow the boning to dry for the specified length of time.

Step 1 - Cut

Step 2 - Smooth

Step 3 - Dip

Finishing the Corset

For a double layer corset, boning channels are created by top stitching the fashion fabric to the lining. For this example, foldover elastic is used for the edging.

1. For the first edge of the boning channel, sew within an 1/8" (2 mm) of the side front, side, and side back seams.
2. Insert a length of boning next to the stitching from Step 1, then use a zipper foot to sew the other side of the boning channel.
3. Hand baste the foldover elastic to the corset's lining, aligning the elastic's center crease with the corset's bottom edge.
4. From the lining side, use a zigzag stitch to sew the bottom edge of the foldover elastic to the corset.
5. Fold over the elastic to the fashion fabric side of the corset and hand baste in place.
6. From the fashion fabric side, use a zigzag stitch to sew the edge of the foldover elastic to the corset.
7. Insert the boning into the sewn boning channels.
8. Remove the basting from the corset.
9. Sew fold over elastic to the top of the corset.
10. Add lacing and a lacing or modesty panel as described in Construction Basics Adding the Lacing.

Completed Corset

Adjusting the Pattern
for an Underbust Compression Corset

The first step in creating this corset is to make a paper copy of the Underbust sloper pattern. Do not copy the seam allowances from the sloper, only the sewing lines.

There are two basic changes that must be made. The first is to restyle the side seams to reduce the width of the corset at the waist by 3" (76 mm). The second is to change the patterns for for installing the separating busk and grommets.

Restyling the Seams to Reduce the Waist

1. Use pattern paper to copy the Underbust Corset sloper. Do not include the seam allowances.
2. If precut boning is to be used, adjust the bottom of the corset as required to accommodate the available lengths. The boning should be 1/2" (12 mm) shorter than the distance between the edge bindings. For this example, this is 1-3/4" (44 mm) shorter than the height of the corset at each boning location.
3. Determine the amount you want to reduce the size of the corset at the waist. In this example, the waist is reduced by 3" (76 mm).
4. Divide the amount from Step 3 by the number of seams of the corset pattern. In this example, there are 3 seams: SF, Side, and SB - hence 3" divided by 3 = 1".
5. The patterns are for half the body, so divide the amount in Step 4 in half: 1" divided by 2 = 1/2".
6. Both sides of each seam will be reduced equally. For example, the side seam will be reduced on both the side front and side back panels. To determine this amount, divide the amount in Step 5 by 2: 1/2" divided by 2 = 1/4".
7. Apply the reduction from Step 6 to the side front and side seams at the waist, drawing smooth curves to restyle the seam lines.
8. Determine the amount you want to reduce the center back line for the lacing. In this example, the center back is brought in 1-1/2" (36 mm).

Adjusting for the Grommets, Busk, and Edging

For this example, the grommets are installed in lacing bones. This configuration provides a secure installation for the grommets and eliminates the need for separate bones on either side of the grommets. The size of the grommets depends on the size of the holes in the lacing bones. The thickness of the lacing bone affects how much of the shank of the grommet will be available. In this example, the overall thickness is minimized by eliminating the seam allowance at center back.

For the separating busk at center front, this example uses a facing that covers the busk and is then trimmed. This minimizes the bulk and maximizes the stretch of the center front panel.

Completing the Compression Pattern

1. Determine the placement of the lacing bone.
2. If needed, adjust the position of the side back seam. It can be moved out from center back by increasing the width of the center back panel, then subtracting the same amount from the side back panel. In this example, the side back seam is moved 1/2" (12 mm) out from center back.
3. Adjust the shaping of the side back seam at the waist by the same amount as the change that you made to the side front and side seams.
4. Add the width of the bra back elastic to the top and bottom of the corset for the edge allowance. This increases the overall height of the corset pattern similar to the way a seam allowance would.
5. Create a facing for the opening busk that is the width of one half the busk plus two 1/2" (12 mm) seam allowances. This facing should be the height of the corset.
6. For the lacing bone, measure out from the finished edge the width of the bone plus 1/2" (12 mm) seam allowance. This will become a facing.
7. Draw 1/2" (12 mm) seam allowances to the sides of all pattern pieces.
8. Add sewing notches and label the pattern pieces clearly.
9. For a left and right side, cut two of each pattern from the fashion fabric.

Paper Pattern with Fabric

Installing Lacing Bones

For this example, lacing bones are sewn into the center back panel before the holes are punched for the grommets. This ensures an accurate placement for the grommets. Lacing bones are specific to the size of the grommets. For this example, the lacing bones are for a 00 size grommet. Lacing bones can be cut to length as described for the white steel bones described in Adding the Lacing.

1. Verify that your punch will fit through the hole on the lacing bone.
2. Sew a line of top stitching to indicate the finished edge of the center back panel. In this example, that is 1" (24 mm) in from the edge of the fabric.
3. Fold the fabric along the top stitching, wrong side together, then pin the lacing bone in place.
4. Use a zipper foot to stitch the lacing bone securely in the center back panel.
5. Switch to a regular sewing foot and sew a line of zigzag stitch 2 mm wide by 2 mm long close to the stitching that is holding the boning in place.
6. From the wrong side, trim off the excess seam allowance close to the zigzag stitching.
7. Use the lacing bone as a guide to insert the grommets as described in Construction Basics Adding the Grommets.
8. Add the busk as described inBusk Inserting the Opening Busk.
9. Sew the body of the corset, including the boning casing, as described in Construction Basics Sewing the Corset Body. The casing should not cover the edging allowance at the top and bottom of the corset.

Trim

Add Grommets

Sew the Body

Add Bone Casing

Sewing Bra Band Edging

If possible before adding the edging, verify the fit of the corset for this combination of fabric before proceeding.

Bra band elastic, also called plush back elastic, can be used to edge a corset. This process requires adjusting the top and bottom of the corset pattern as described on page 9. The instructions below show how to add the elastic to a corset.

1. Pin the bra band elastic to the corset's good side with the plush side of the elastic up and the elastic's smooth edge aligned with the top of the corset.
2. Use a 2 mm wide, 2 mm long zigzag stitch to sew the elastic close to the decorative picot edge.
3. Trim the edge allowance down to the zigzag stitching from Step 2.
4. Turn the bra band elastic over to the inside of the corset and hand baste so that the picot edge is just showing on the good side of the corset.
5. Use a 4 mm wide, 2 mm long zigzag stitch to sew the smooth edge of the bra band elastic to the corset.
6. Insert the boning into the casings.
7. To sew bra band elastic along the bottom of the corset, follow steps 1 to 5.

Finished Corset