Tuesday, 27 December 2016

Craftsy 2: Designer Techniques for Bras

  • Lesson 1: Turn a full band bra (eg Pin up Girls Classic Bra) into a partial band


  • A partial band bra has no frame under the cups and a smaller bridge. This allows greater design freedom. and eliminates the rolling of the bottom elastic of a full band bra, good for large tummies. The underwire channeling turns to the inside of the cup, cw the channeling on a full band bra turning outside towards the frame.  The partial band cups are therefore larger to accommodate the channeling - the full band bra has the seamline on the breast side of the underwire while the partial band bra has the seamline on the chest side of the wire, so the seamline has moved over by the width of the channeling. Cannot switch cups from partial to full band bra but can convert the full band bra pattern to a partial bra pattern, applying same fit alterations as made for the full band bra. Therefore, trace off adjusted full band bra pattern pieces and then make changes into a partial band bra.

Drafting the cups

  • Add the width of the channeling eg 3/8 to the CF line of the upper cup.
  • Add the width of the channeling eg 3/8" to the lower line of the lower cup

Drafting the band

  • Overlap the frame and back band pattern pieces by ½" and tape together. 
  • Draw elastic SA  (½") onto lower edge of back band.
  • Draw ¼" SA around wire line from top edge of frame around to CF.
  • Draw from back band to B notch (where the cup curve starts to go vertical), a pretty straight line. Add ½" SA, joining vertically to the B notch. This forms the back band - the new seamline under the wire down to the bottom of the frame and across the back band. This can either be sewn as one in the same fabric (powernet) or treated as two separate pattern pieces by separating at the band/frame seamline and making from two different fabrics.

  • Make a line from uner the cup to the CF, making an S. This curve should sit a little higher than the bottom of the back band. Add ¼" SA under this line. Therefore, the new bridge pattern piece will be from the new wire seam line down and then across to CF. f


  • Use a washable marker to mark the notches - don't snip, the SAs are only ¼" and are too prone to getting cut into.
  • Add stickers to the right sides of the fabric pieces.
  • Staytape the neckline and underarm area of the upper cups from strap to wireline, using either twill tape (can be bulky) or a strip of tricot (= duoplex) - use a shorter stitch length and sew with ⅛" seam so it remains invisible after the elastic/straps have been sewn in place.
  • Sew inner lower cup to outer lower cup and press seam open.
  • Sew upper cup to lower cup at internal seam line with absolutely no stretching, from point to point, with just a pin at either end. Stitch using an edge stitch foot in ¼" seam with the lower cup on top (helps prevent the seam from stretching out) and a stitch length of 2.5. Make sure not to stretch the upper layer as you sew.
  • Press cup seams open over a newell knob screwed onto a piece of wood with lots of steam. Topstitch both sides of the cup seam with a 3.5 stitch length at 1/16", pulling the seam apart as you go. Trim the SAs back to the stitching line using Pelican scissors.
  • Sew the straps to the upper cups, the square end of the strap to the cup not the tapered end, so that the straps lie pointing away from the midline. Press the strap seams closed and up towards strap. Topstitch 2 lines of stitching on the strap at 1/16" and ⅛"
  • Form the bridge. Lie two rectangular pieces of bridge fabric (either same e.g. duoplex, or could cut e.g. sheer cup lining + decorative fabric; add interfacing layer if needed - aiming at 0% stretch for the bridge) bigger than the bridge pattern piece, RS together. With a washable marker, draw around the bridge pattern piece. Sew with a straight stitch, through both layers, along bottom of bridge with SA 1'4". Cut around outline, trimming off corners. Clip into curve and turn to the RS. This gives a much more accurate line than cutting the bridge pieces out first and trying to sew that tiny seam line. Baste the raw edges at ⅛".
  • Sew bridge to cups. With RS together, pin top of bridge to top of cup only then walk the two curves together using a stitch length of 2.5. At the bottom of the bridge, don't stop, continue stitching just the cup all the way along the wire line = stay stitching. Check that the two cups are even across the bridge.
  • Sew elastic to the back band. Sew elastic (½ - 3/4" wide) to the bottom of the band (note that the band may be cut all in one or in two with a seam), laying RS together with picot edge facing in and stitching with a zig-zag (width = 2.5. length = 2) close to the picot edge. Trim SA, turn elastic to inside and stitch with 3-step zig-zag (width = 5, length = 2.5).
  • Sew cups to the band. Sew the edge of the band to the side of the cup, matching notch B, using the staystitching as a guide and sewing to the bottom of the elastic. Will need to stretch the band to fit. This leaves the lower edge of the cup raw (will get covered by the channeling).
  • Sew channeling to the cups. Precurve the channeling with steam. With RS bra facing up, fold back band on right in up over the cup and the other back band/cup/bridge in and over the cup, exposing the lower wire line.

  • Lie the channeling from the band end with the channeling curving away from the curve of the cup. so that it will turn into place, along exposed seam allowance. Stitch, starting about 1" from the end of the band, right on the edge of the channeling, following the staystitch line and pulling the channeling into place. Stop about ½" before the top of the bridge. Turn the channeling to the inside.

  •  Add neckline elastic. Pin tails of channeling down, out of the way.
    • Pin the cup SAs towards the bridge CF
    • Stitch the neckline elastic (34" long) down the inside edge of the strap (not stretched), across the top of the cup (not stretched), across the bridge (not stretched) and back up, with RS together using a zig zag (L = 2, W = 2.5) and keeping the stitching close to the (inner) decorative edge of the elastic. Don't flip and stitch down elastic from RS yet.
  • Complete bar tacks. Bar tacks stop the underwire from pushing out of the channeling.On inside, at CF, fold neckline elastic down and lay both channels on top of the trim. Mark upper and lower edge of trim on channeling. Lift neckline elastic up out of the way. On lower line, through the channeling only, straight stitch across and back (L = 1), then zig zag across and back (L = 0.8, W = 1.5).Cut channeling off at upper mark so that the ends will fit under the neckline trim.
  • Flip neckline elastic to the inside and stitch from the RS using a 3-step zig zag (L = 1, W = 4)  making sure the channeling follows the cup seam and the ends are tucked under the neckline elastic, using 1 pin at the CF. The bar tack should lie along the lower edge of the neckline trim.
  • Topstitch the channeling. Start at the bridge and sew 1/16" from the channeling edge, pulling the layers apart so no pleats form, sewing from the wrong side. Make sure that the outside edge of the channeling matches up with the seamline at the very edge. Sew right to the end, stitching down the free end of the channeling.
  • Insert the underwire. Insert the underwire with the low end toward CF.
  • Add the side elastic. Choose 5/16" or 3/8" wide elastic, 22" long. Sew elastic along the outside of strap (not stretched), along the side of the cup (stretched by 1" - make sure to hold the fabric either side of the needle so the needle doesn't break), and along the back band (slightly stretched) using a zig zag (L = 2, W = 2.5). Sew with RS together and picot towards the strap. Flip elastic to the inside, trim the strap SA and sew near picot edge using a 3-step zig zag (L = 1, W = 4) from the RS.
  • Add the strap elasticStrap elastic is available in 3/8 - 1" widths with fancy edges, a satin face and a plush back. Sliders and rings should be the same size as the elastic width. Typical is 3/4".
  • Cut 10" of the elastic and push one end up through the slider, over the centre bar and down the other side, forming a short ½" tail. Stitch from the RS using a short straight stitch and zipper foot, across and back twice (= 4 rows).
    • Slide ring onto strap with WS up. Take tail and pass up through slider, over centre bar and down the other side, leaving a long tail.
    • Check that the width of the back band is the same size as the hook and eye closure and if not, trim to fit.
    • Pin the strap to the lower curve of the band on RS. Line the straight edges of the strap and band up together than straighten the fabric to fit the straight elastic even though there might be pleats formed and pin. Stitch on the inside edge to top of bra band, form 2 steps across top, then stitch down middle of strap, and 2 steps across the bottom, using a lightning stitch.
    • Thread fabric strap though ring, from front to back, and pin in place. Stitch in place with straight stitch, across and back, twice.
  • Attaching the hooks and eyes

    • Note that the LHS of the band has the eyes.
    • Clean up the back band edge.
    • Insert band into raw edge of eye band. Stitch across the end of the band, turn, take 2 steps, sew across to the other end, turn and take 2 steps back to the beginning.
    • For the hook band, insert in the same way as for eyes, or, if there is no prefinished pouch for the hooks but instead a flap, fold flap down and under bra band and stitch in place from hook side using a straight stitch and zipper foot to get close to hooks.

Lesson 2: Modifying upper cups and straps


  • The trifecta of the neckline trim = inside strap, top of cups and top of bridge. In a traditionaly finished bra, the neckline trim takes care of all three of these together. However, if one of these is finished in a different way, the others will be affected.
  • Below are different finishes that you can pick and choose for different looks.

Straight top cups

  • No neckline trim, the cup fabric is doubled and gives a clean, tailored look. Can be used on full or partial band bra. Allows a variety of strap styles as there is no strap tab on the upper cup.
  • Drafting the upper cup. Draw a line across the top of the upper cup including across the strap tab.

  • Continue the underarm curve on the upper cup up through the strap tab to meet the first line.

Long or short tapered straps

  • Short tapered strap. Fold lengthwise, WS together, and lie on top corner of upper cup, RS together, keeping in mind the ¼" SA that will be sewn. If using neckline elastic along the top, sew this in now. If doing a straight double cup, insert the short tapered strap in between the two layers and sew in place.

  • Strap elastic finishes the underarm curve edge of the strap.

Padded straps

  • Good for large, heavy cups. Padding can be fully enclosed or not.
  • Draft the strap. Tape usual strap pattern piece to a piece of paper and mark where the shoulder will be - for most women this is 6 - 8" above the upper cup. At that mark, mark ¼" each side of the strap and then draw tapering lines to the original strap lines, using a French curve.

  • The padding doesn't cover the full width of the strap, because turning the elastic needs room.  ie turn of the cloth. Mark 3/8" allowance on strap pattern piece on all 3 non-tapered edges; at the tapered end stop 3/4" away from the edge.
  • Use Cut n Sew foam (not craft) in ⅛" thick. Cut foam to pattern above. Use a glue stick to glue padding to WS of strap. Sew strap to upper cup making sure to catch the padding into the seam line.
  • Sew first pass of underarm elastic and first pass of neckline trim to the bra cup. Sew the second passes of the elastic and trim, covering the edges of the foam padding. Consider the width of the strap when selecting the width of the 3-step zig zag and make it proportional.

Lesson 3: Modifying the Frame

Thin Full band bra

  • can be done, involves re-drafting the pattern.

Gothic Arch Bra

  • Can only be drafted for a full band bra, has a high arch under the bridge.
  • On the frame pattern piece, draw from the lower edge, under the cups, continuing the line straight up towards the CF to a point ½' up.

  • Clip the CF ⅛" less than the width of the band elastic. This is because the lower band elastic will be sewn on in two parts. After sewing the band to the frame at the sides, stitch the lower elastic, RS together and with usual zig zag, stretching under the cups, from the band edge up to the CF clip, making sure that there is a tail of free elastic that comes up to the edge of the cup. Lie the second piece of elastic over the first elastic at the CF clip so that you start stitching at exactly where the first elastic finished.

  • Flip the lower elastic and sew from the WS, inner edge with a 3 step zig zag, from band end continuing to the end of the elastic, allowing the elastic to curve up and sit across the bridge toward the cup, keeping the other elastic out of the way.

  • Sew the other elastic in place, starting at the CF, making sure the elastic tails are even across the bridge. This forms a criss cross that is visible from the RS. If you don't want this, make the criss cross just the width of the elastic.

Front Closing Bra

I can't imagine me ever using this technique but never say never! 

Keyhole Bridge

I can't imagine me ever using this technique but never say never! 

4. Modifying the Back Band

See the class for modifications

Fold over elastic

  • Keep in mind that the FOE is an edge finish i.e.. no seam allowance, so trim this off.
  • FOE has a narrow side and a slightly wider side. The narrow side should be on the right side of the fabric so that when you zig zag from the RS, the second pass of sewing, you are guaranteed to catch the wider back side.
  • Sew in two passes with no pinning or glueing - lie WS of FOE to WS of fabric, with FOE lieing open and flat and lining up the centre line of the FOE along the edge of the fabric, and sew with a small zig zag (W = 1.5 L = 1.5) close to the edge, leaving a 1" tail of FOE. Fold FOE over to the RS and sew with same zig zag from the RS, continuing along the 1" tail.. The tail can be used as a strap extension that a ring can slide on to, taking the place of the strap elastic on a traditional bra.

5. Power Bars

Power bars can be used in both full and partial band bras. They lie on the outside edge of the cups and push the breast forward. They can be internal, in seam or external.

  • Internal power bar.  Mark the ¼" seamline on both the upper and lower cups, from the outside edge to the apex point. Mark a point about half way along this line. Lie the lower cup over the upper cup with the outer edge seamline point and the marked point matched up. Tape in place. Draw a straight line from the inside corner of the strap through the marked point and down to the bottom of the lower cup.

Trace off the power bar pattern (the left of the line). Mark the DOGS on the pattern piece - this is parallel to the strap seam. Tape long edge of pattern piece to the edge of a piece of paper, fold over and trace so that there is a full pattern piece. Make the power bar out of the same fabric as the cup e.g. duplex or 15 denier, nothing too thick. Fold the fabric in half along the long, bias edge and sew to outer edges of cups.


  • In seam power bar.. Less visible. Complicated.
  • Ruched external power bra. For fashion rather than support.

Modifying Cup Seams

How to draft seamliness.

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