Bellini Sewalong: Guest post on the full bust adjustment from Kadiddlehopper! September 11 2014

Howdy, y'all! Katie from Kadiddlehopper here and I am so pleased to be guest posting here on the Capital Chic blog! Sally's patterns are truly inspired and I am honored to be just a small part of this project. I'm here today to show you all how to do a Full Bust Adjustment (FBA) on your Capital Chic Bellini top. If you found that your Bellini was a bit too snug for your girls, then this post is for you!
The method that I will show you today will add a dart to your pattern. The dart provides shaping around your bust, increasing the space without sacrificing a sleek fit. So, let's jump right in! The first step is to figure out how much additional space you want to add.
Here is the method I like to use. Start with your muslin. Since I made a Bellini previously, this is a finished blouse, but this would be the same with your muslin. Try on the muslin (either on yourself or a dressform that has the same bust measurement you do) and arrange it so that it fits the bust the way you like it. There will be a gap in the front. Measure the space between the center fronts and divide that measurement in half for the amount you will alter your pattern piece. In this example, I have a 2 inch gap, so I will do a 1 inch FBA. If you choose not to do a muslin, simply measure a shirt you have that fits you well in the bust, and compare the finished bust measurement of the Bellini. Use that difference and divide in half for your FBA.
Now let's start altering our pattern. You'll need the front piece and the front facing. I have traced my pattern pieces onto tracing medium. This is an optional step, but I find it easier to manipulate a thinner pattern, and it also helps not to have the distraction of the other size lines on your pattern piece.
The next step is to find your bust point. The bust point is wherever you happen to be the fullest. For most women, this is the nipple. It may not be for you though, so just pick the bit of you that sticks out the furthest. I generally find this point by pinning the front and back pattern piece along the shoulder seam line, and draping it over my shoulder. Line up center front with your center front and make a mark at your bust point. Note that there are two marks in my photo. This is the power of a good bra. It makes a difference. Wear the undergarments that you plan to wear with your Bellini.
Now that you have your bust point, you are ready to mark your alteration lines. I always start with the bottom line, which you mark from the hem to the bust point. This line need to be parallel to center front. Continue that line at an angle from the bust point up to the shoulder. Choose a point roughly in the midpoint of the shoulder seam. Stop your line at the seam line (5/8 inch from the cutting line). The final line is roughly where your dart will be. It should begin a few inches below the underarm. This line points at the bust point, but does not intersect it. Cut your pattern along those lines, leaving the pattern intact at the shoulder point and at the intersection between the dart line and the bust point.
Since you didn't cut through the shoulder seam line or the dart point, you have "hinges" in the pattern at those points, marked by arrows above. Anchor the center front area of your pattern piece. You can see my large pins holding it in place, but pattern weights also work. With the center area stable, shift the side of the pattern away, keeping those edges parallel. Separate them by the amount you calculated in the first step. For me, it was one inch. You'll also shift the side piece downward in order to keep your pattern piece flat. As you shift it, the dart area will open naturally.
Use some scrap paper or tracing material to fill in the space you've opened up. Leave the bottom 6 inches or so of the center part of the pattern free so that you can shift it down in the next step. You can also fill in the dart area at this point, but make sure that you leave some paper hanging off the side so that you can true the dart points.
Now we need to re-align the hem. Part of the FBA alteration adds length to the front to travel over your bust. You need to compensate for that added length at the hem. Remember that bit you didn't tape? Draw a line through that section, perpendicular to center front and cut off the bottom. Align it with the hem, making sure to keep the center front aligned as well. Tape it in place now and fill in the gap with tissue.
Your pattern piece should look something like this now. I like to trim off the extra tissue within the pattern piece at this point, but be sure to leave that extra at the side seam for your dart, which we will draw and true next.
Let's address that dart we created. During the process of making the FBA, the original dart point is shifted down. We need to bring it back up so that it points to the fullest part of the bust, the bust point. You want the dart tip to be 1-2 inches away from the point. The fuller your bust, the farther away your dart tip should be. I put mine about 1 1/4 inch away. Mark your new dart point and draw lines from the side seam up to the point. These will be the stitching lines for your new dart.
The next step is to "true" the side seam cutting line to allow for the dart to be caught in the seam. Fold your pattern piece just as if you were sewing the dart, with the two lines together and pin in place. If you are using a sewable tracing paper, you can even sew the dart. Fold the body of the dart down toward the hem and draw a line along the side seam, catching the extra paper from the dart. With the dart still folded in place, cut along the line you drew at the side seam.
Unfold your dart and you have a nice smooth allowance for the dart uptake. Looking good!
We're in the home stretch now! You're done altering your front pattern piece, but you need to lengthen your facing piece to match. For Bellini, you can just add to the bottom edge, since the hemline is straight at this point, but that won't work with a curved hem.
Since Bellini has a nice lengthen/shorten line right there on the facing, I just cut along that line. Add enough length so that the facing is the same length as the front of the blouse.
Fill the gap in with tissue and you are ready to cut out your blouse! When constructing your Bellini, be sure to sew your darts first, pressing them down toward the hem, then follow the instructions just as Sally has written them.
And wear your beautifully fitting Bellini with pride! 
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Thanks so much Katie for showing us how to do an FBA for this blouse!
Will you do an FBA on your Bellini? Do you have any questions on this technique? Please leave a comment below.