Hello there! Welcome to my first “real” post as an editor of the Curvy Sewing Collective. I’ll be kicking things off with a series of posts on a topic that’s close to my heart: Dealing with large Full Bust Adjustments (FBAs) and the Big Honkin’ Darts that can result when you’re performing a large FBA (greater than 1.5-2″) on your pattern pieces.
Many commercial sewing patterns are drafted for women with a B-cup pattern size, meaning women who have a 2″ difference between their high bust measurements and their full bust measurements. If your high bust and full bust differ by more than 2″, you might need to choose a smaller pattern size than indicated on the pattern size chart and perform an FBA to get a good fit with your pattern.
If you’re not familiar with FBAs but suspect that you might need one, the CSC already has several posts discussing this alteration, which I recommend reading before continuing with my post:
The CSC has more posts related to FBAs, but I’m listing these two because they’ll get you up to speed on one of the most common FBAs: an FBA on a darted bodice, which is what I’ll be discussing in this post.
Differences between a small FBA vs. a large FBA
Most online tutorials and fitting books that describe how to perform a FBA typically deal with only adding a small-to-moderate amount of ease at the bust. The most common scenario that I’ve seen is a 1″ FBA. But what if your pattern cup size is much larger and you need to do, say, a 3″ or even a 4″ FBA?
Adjusted pattern pieces can look significantly different when you’re doing a 1″ FBA vs. a 3″ FBA, and if you’re doing a 3″ FBA, there’s a good chance that you might need to perform some additional or alternative pattern alteration steps to get a fit that you’re happy with for your garment. My goal for this post is show you the differences in appearance between a smaller FBA and a large FBA (hint from the post title: the dart gets really big) and discuss your options for dealing with those differences.
Let’s start by looking at a small slash-and-spread FBA, like you’d typically see in most fitting references. Note that in my images, I’ve drawn in seam allowance lines and that we’ll be working with quarter-scale patterns in this post.
Start by drawing in your typical FBA lines:
Slash and spread your pattern pieces to perform an FBA that would be approximately 1″ on a full-scale pattern. These shapes should look familiar if you’ve read through other slash-and-spread style FBA tutorials:
But what happens to those pattern pieces if you triple the size of the FBA? Let’s swing the side piece of our pattern out to mimic a 3″ FBA:
Note these key differences:
- Armscye: The armscye angle is much sharper in the larger FBA. A little bit of a sharper angle is a good thing in that it can help minimize that fold of fabric above the bust that larger busted women sometimes get, but this example shows a pretty extreme angle.
- Bust dart: Look at the size of that dart! In fact, you could call this a Big Honkin’ Dart.
Large FBA = Large Dart
Let’s talk about that Big Honkin’ Dart a bit. The Big Honkin’ Dart might solve the issue of adding more ease to the bust, but it also creates a few fitting problems of its own. If you’ve ever sewn a garment or a muslin with a Big Honkin’ Dart, you’ve probably personally encountered the following issues:
- Very large darts are very difficult to sew cleanly. I’ve read that if you have any more than 2.5″-3″ between the legs of your dart (depending on what you’re reading), you’ll exceed the limit of being able to sew the dart cleanly.Think about it this way: the larger the distance between the dart legs, the more fabric you have to account for when you’re trying to sew to a gradual point at the dart’s tip. If you’re backing the tip of the dart off from your bust apex, as many large busted women need to do, you’ll have even a shorter distance to sew to a clean point at the dart tip.
- Once sewn, you now have a large flap of fabric on either side of each breast, adding bulk where you probably don’t want any additional bulk.
Here’s an example of a Big Honkin’ Dart in a muslin that I sewed a few years ago to illustrate some of these points. In particular, look at that big, floppy, unattractive fold of fabric hanging off the side of my bust.
(Yes, this blouse muslin had numerous fit issues beyond the Big Honkin’ Dart.)
Okay, so now that we know that our Big Honkin’ Dart is causing us a few issues. What can we do to fix those issues? You have several options for dealing with a Big Honkin’ Dart, depending on where you’re at with your sewing project and how comfortable you are with pattern alterations. The following table summarizes each of these options:
|Solution||When to use?||Pros||Cons||Comments|
|Trim or serge off dart excess.||You’re working on your real (not muslin) garment.||Gets rid of dart floppiness.||Doesn’t fix other fit issues.||Use this fix only when it’s too late to go back and make changes to the paper pattern.|
|“Cheater” FBA by grading to a larger size at the armscye.||You’re in a hurry or aren’t comfortable with more complex pattern alterations.||Decreases the size of the FBA you need or eliminates the FBA altogether.||Doesn’t fix other fit issues; may lead to a too-large armhole for your body. Doesn’t add length over the bust.||Tends to work better for knits than wovens.|
|Y-Dart FBA||At the pattern alterations stage.||Decreases bust dart size and fixes other FBA-related fit issues.||Depending on your build, might add too much fabric to your upper chest area.||Some sewists swear by this alteration, but it doesn’t produce the same results for everyone.|
|Rotate all or part of the bust dart to another location on the bodice.||At the pattern alterations stage.||Decreases bust dart size or eliminates bust dart. Fixes other FBA-related fit issues.||Not every bodice pattern has an intuitive location to add/rotate a dart.||My favorite way to deal with a Big Honkin Dart, as long as there’s a good spot for rotation.|
In upcoming posts, I’ll go into more detail about how to do both the Y-Dart FBA alteration and how to rotate all or part of a bust dart to another location. In my opinion, these pattern alterations are the best way to tackle the Big Honkin’ Dart issue, if you’re still at the muslin or pattern alteration stage and are willing to slice up your pattern a bit.
If you’ve been struggling with trying to perform and fit large FBAs, I hope that this post provided a decent introduction to one of the big issues that you might encounter.