Demystifying the Full Bust Adjustment (FBA) - tutorial

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Why and when you need to make an FBA 

Most patterns are constructed with a cup size B in mind (sometimes a C). A cup size is a relative measure and not a fixed volume. That means that you can be a B-cup and still span across sizes 0-18 (or whatever) - the volume of a B cup size 18 is a lot bigger than a B cup size 0 . If the pattern maker should cater for all cup sizes they would need to make one pattern for every cup size AND every size!! Imagine that pattern sheet!!! Gee, that would be crazy, which is why they stick with only one cup for all sizes and let us do the adjustments at home. It was so much simpler when women were all Barbies. ;-)

See that should probably answer your question on WHY ON EARTH clothes in the store never ever fit you right. Same reason. All made for the same one cup size...

Now. For those of you who are a little intimidated by this, or that may be afraid that you are changing the design of the garment. Chill out. It is really quite simple and this is done to KEEP the design and not to distort it.

I will be showing FBA on the Alma Blouse from Sewaholic Patterns. 

Signs that you need an FBA

Fashion photo borrowed from Ottobre 5/2011, sewing pattern magazine.

If you would solve the above problems by just wearing a larger size, then the fit around your waist and shoulders will not be great. Just because the boobs are big, you haven't changed your frame, right?

In this picture I am wearing my first Alma. I did just that, i.e. no FBA and went with a larger size.  No complete disaster but there is definitely a lot to ask if you're picky, like me.

No FBA, larger size to fit the bust.

Another 'classic' we are all much too aware of, is the buttoned shirt where you are afraid to move your arms in case the buttons will pop off (have you ever taped, sewn, safety-pinned or glued the fabric in place between the boobs to feel secure?). I was just done wearing shirts altogether until I learned about FBA.

Another graphic to illustrate this (I am such an artist!):

You see that the green "fabric" needs to be way longer than the red "fabric", even though the neck and the waist are in the same places. This drawing is necessary to calm those of you who fear your garment will be bigger and tent-like after a FBA is done. It won't be, but your boobs will fit.

The FBA process

Now there are certain steps to take in order to succeed with the pattern alteration. I am sure there are many different ways to do this, but this is how I do it. If you have a better way, do tell! I am eager to learn!

#1 Find your size and trace your pattern!!

Really goes without saying, but you will be doing some cutting so don't spoil the original sheets.

What size to cut? It is not always a clear answer to that, since we are all different. Some women have broad shoulders and should select a size that accommodates them, while others have a tummy to include in the game. If you have sewn some in the past you may have an idea on how the rest of your frame fits into patterns? If not. Do measure your "high bust" measurement instead. That is putting a tape measure under your armpits, around your back and OVER your bust (as opposed to across your widest part). Then measure your waist, hips etc and select the size that is closest to fit.

For myself I've learned that my shoulders are pretty average and usually fit into patterns without alteration so I just go by the waist measure and that's my size. The boobs will be taken care of soon.

My measures:

High bust (as described above): 36 inches

Waist (my skinniest part of the torso): 30 inches

According to the pattern back table those measures are exactly a size 10. Meaning that if I had a B-cup, a size 10 would fit me like a glove. For reference my real bust measurement is 39 inches = 3 inches larger than the size 10 of the table. 

So, I will now trace a size 10 exactly as is and cut it out.

Size 10 straight from the pattern. Darts in yellow.

#2 Find your apex and make sure the darts point to it.

This step is more important than you might think, you'll see why in a minute, so don't give this a miss.

If you look at the pattern, all darts usually point towards the same point - the apex. Apex being the highest point of your chest (for most people, the nipple). If you run right into a wall, your apex is the point that hits the wall first, unless your nose beats you to it ;-)

Mark your apex on the pattern. Is it in the same place as pattern wants it to be? Congratulations, move on to #3. If not, go to a plastic surgeon and have your nipples moved into the correct location. OR, you can alter the pattern, which is what I prefer. It is cheaper too.

Original apex marked yellow. My apex marked blue.

 As you can see in the picture my apex is quite far off the original location.  Now I need to make sure the darts point towards the blue X instead of the yellow.

The easiest thing is to move the waist dart. Just put a piece of paper over the yellow one and copy it. Then put the copy in the position you want UNDER the pattern sheet and then just trace a new one. My pattern now looks like this:

Blue is my new waist dart.

Now there are two ways of changing the bust dart so that it points towards YOUR apex. You either just start at the side markings of the dart and adjust the angle of the point, then true up the dart legs. The reason I don't prefer to do it this way is because you then change the design of the garment (if you're picky). The bust dart will then, in my case, be tilted slightly downwards instead of more upwards. 

The other way to do it is to lower the entire dart the same amount as your apex is lowered, in my case 3 cm. Before you do that it is wise to fold up the current dart and mark the sideline of the "sewn" garment so that you know what it should look like after you have moved the dart.

Blue is new bust dart, 3 cm lower than the yellow.

Cut off the paper between the yellow dart legs (marked blue line) and fold up your new dart to verify the shape of the side seam.

Okay, so why was all this hassle important again? Well, now that everything points towards apex you can go crazy in the next step and still be sure that you add fabric only in the right places - without adding to your waistline, armpits or other places!!! And it kind of looks shitty when a dart points in the wrong direction too. And this goes for other types of FBAs too! As long as you keep your FBA in the middle of dart and/or tuck markings you are not distorting the design - it doesn't matter from what place or angle the dart/tuck originates!! Beautiful! 

So, NOW we can actually start doing the FBA!

#3 - the actual FBA!!!

If you remember from #1 above, I needed to adjust the front piece by 3 inches = 1,5 inch (4cm) on one pattern half. A rule of thumb in adjustment is 1 cm per cup size (counting from B), which would in that case suggest that I wear a size F, which I do :-)

But - another aspect to take into account is the "finished measurements" of the garment. For my bust, being 39'', the ready measures for the garment around the bust is 43'' which is more ease than I like, even for a loose fitting blouse. Therefore I'll do an FBA of 2cm on a half front, instead of 4cm. 

Time to cut up the pattern! For this step I strongly advise working over a grid since it makes life so much easier.

Remember I said we want to cut within of our darts to not distort the design. 

1. The first cut is vertical from the bottom, through the waist dart, to the apex
2. The next cut is from the apex to the armpit. Aim for anywhere on the lower 3rd of the curve - but DO NOT cut all the way through!! Leave just a tiny piece of the paper.
3. The next cut is from the side through the bust dart up to the apex - but NOT all the way, leave a little just before reaching apex.
4. The last cut is a horizontal cut from the waist dart to the centre fold side. Cut all the way through.

All the cuts are marked in red on my pattern:

Now remember for my FBA I wanted 2cm on the half front. When I cut and spread I want 2cm space in every direction:

Shove a new piece of tracing paper underneath and draw the darts again and true up the legs:

Note! Your new darts will be way bigger than the old ones (compare the blue bust dart with the old yellow one). This makes total sense - try fold a paper into a cone. I tall cone means longer dart than a short cone, right?! The waist dart now is extended all the way down, because I don't want to add width to the waist, but you can shape it differently if you like.

And if you wanna be fancy then trace the whole thing on new paper and there you go!!

The finished piece!! 

No go sew! The result will look something like this (the blouse has been worn for a couple of hours in the picture if you wonder why I haven't ironed it properly).

Still quite roomy and comfy but skims off the body nicely. Compare with the non FBA'd pic from the top... I rest my case.

/Alexandra