Adding to an Existing Dart

Part Deux of our Full Bust Adjustment festival, this tutorial will show you how to increase the size of an existing dart. I'll be using our Party Dress pattern (Kwik Sew #3521) as an example.

Most commercial patterns draft for a B cup, so many people have to alter up or down accordingly. On some patterns, you can fudge it a bit, or just get by - this is one of those patterns for me. It has always been a bit snug in the bust - but workable - now it's noticeably tight. My weight goes up and down a lot, and of course it all settles in the bust which means I have to alter almost everything I own. Hooray! Plenty of practice... Here's a picture where you can see that the existing dress squishes the bust a bit:

So, we'll be using the same slash-and-spread technique as we used previously in the Full Bust Adjustment aka FBA post along with the same supply list and cup size measurement chart. It might be a good idea to read through that post to refresh your memory - you can refer to it for all the step-by-step pictures I'll talk about below.

Here we go!

1. Locate and mark the bust point if it's not already marked on your pattern (or if it's different from the pattern). Measure the width of the existing bust dart (that's the side seam dart - the ones on the bottom are called waist darts) from leg to leg. My dart measures 1 3/4" wide - write it right on the pattern. Then, draw your three lines - one line from the bust point to the waist parallel to the grainline, the second line through the bust point perpendicular to the grainline, and the third line from the bust point to the arm curve. Cut along these lines leaving hinges as shown:

2. On a piece of extra paper, draw a vertical line as a base line, then a second parallel vertical line: 1/2" apart for C cup, 3/4" apart for D cup, 1" apart for DD cup. Tape your slashed bodice piece down along these lines, smoothing all the lines down and spreading the the pattern out along your cuts. Refer to Full Bust Adjustment aka FBA post for a detailed explanation with pictures for this step!

3. To create your new dart, first draw a line perpendicular through the bust point to the side seam. Mark 1" away from the bust point along this line (towards the side seam) - this will be the apex of your new dart. If the apex was right at the bust point, you'd have a bullet bra look going on, pulling it back a bit makes the transition softer. Next, measure the amount on the side seam that was spread open. On my pattern, the cut spread apart 1", so I'm going to add that to my existing dart (1 3/4") to make 2 3/4". Remember different sizes might have different measurements! Measure from your new top dart leg down along the side seam to mark the lower leg of your dart:

4. Measuring from the new apex, mark the same amount down each new leg of your dart. It doesn't matter what this measurement is as long as it's the same and somewhat close to the side seams. Fold along the lower leg and bring it up to meet the upper leg, matching these marks. Tack in place and re-draw the side seam so it's straight. While still folded, use a pin to perforate the side seam along the dart extension so you can draw it in when you unfold it (you can see the perforations on the picture above). The side seam is drawn from the pattern's existing underarm to the waist:

5. The extra paper at the waist can either increase the width of your waist dart or create a second waist dart. If your waist dart will be over 1 1/2" wide, you might want to make two smaller darts. This changes the direction of the fabric less drastically and usually ends up looking better when sewn. Here's what I did:

With one dart, the apex should be 1" below the bust point and centered on the bust point. With two darts, you'll want to split the difference. The center line of the dart should be parallel with the grainline, and the width of the darts should add up to the original dart width plus however much you spread the pattern apart. My original dart was 1 1/4" and I spread my pattern 3/4", making 2". Split in two, each new dart is 1" wide! Make sure you fold up your new darts and even out the waist curve - usually you'll have to add a bit for it to smooth out nicely:

Now at this point, you may be thinking "Ah ha - math! I have conquered the curvy and squishy body!" But alas, you may be mistaken - the true test is to check your pattern by making a muslin and fine tuning it. Here you can see that there is indeed more room for my bust but it's a little baggy:

Never fear! Pulling it in at the side seam just a smidge takes care of the problem and delivers a beautiful fit. Looks like I'll also need to shorten the back slightly to get rid of the fabric riding up - you can see some folding in the back:

I found some great Alexander Henry bat fabric in my stash that I think will be the next party dress! In a few days, I'll post the last installment in the Bust Adjustment series - how to add room when there are no darts - using Colette's Parfait Dress pattern. Until then, deep breath and happy fitting!