BasicsThis post was orginially post on the Lingerie Sew Along blog, which is a private blog. The content was excellent, so I asked the original author, Tina of lingeriecrafter (do check out her blog - she makes some really lovely things!) if I could repost the information. She has graciously allowed me to post it here. I have added some information regarding supplies in blue type.
It took me ages to find a decent line drawing of a bra, but I finally got one from an Indian website. Unfortunately, the terminology there was different from what we use, so I'm just going to add labels here. (Please feel free to correct my usage, and I will make the necessary changes.)
This is a full-band bra with a three-piece cup. Note: A partial band bra will not have the band extending under the cups. There will smaller versions of piece #6, the bridge and #7, the wing that do not connect under the cups.
1. Bra strap attachment
2. Bra strap Straps can be made of bra strap elastic, which is usually plush on one side and shiny on the other - this is what I provide in the kits - usually the larger the size, the wider the strap. Non-stretch straps can be made from the same fabric as the bra for a little more support and no stretch. Straps also can be a combination of stretch/non-stretch so that there is a little give for wearing comfort.
3. Slider (for adjusting bra strap length) These come as pairs, and you'll need two sets for each bra. The ones in my kits are metal coated nylon, no plastic to possibly break, and of course the nylon will take dye.
4. Hook and eye closure Closures come in a variety of widths, but the main thing to note is that the larger the bra and wider the back band, the more hooks are needed. You can always trim down a back closure to a smaller number of hooks/eyes if you need to. The edges will not fray.
5. Bra cup. The number is exactly on the apex - the point furthest away from the body. Bra cups can be made from a variety of fabrics, but it best to follow the guidelines for the pattern you are using; some cups are stretch and some are not. The advantage of using a one way stretch fabric (like one-way stretch tricot) is that you can cut the sections that need stretch with the direction of stretch and those that do not in the direction in which there is no stretch. In general, larger cups sized pattern may not be drafted for stretch fabrics as a non-stretch or very low stretch cup will better support a larger figure.
6. Bridge This is the center section between the cups. It is almost always non-stretch. The bridge may be interfaced to give it strength. A small piece of fusible interfacing can be used, so if don't throw away little scraps!
7. Wing As noted below, some patterns have this piece combined with piece #9, so it might be cut with stretch. For larger sizes, this seam is an advantage because it is a place to add a small piece of boning for extra support.
8. Power bar or sling Not always used in all bras; nor will you find it in all patterns. This is an optional piece inside the cup which provides extra support, especially for the larger sizes.
9. Bra back This portion of the bra is usually cut with stretch and can be made of stretch fabric, powernet or other fabrics like lace or sheer with powernet underneath for support
10. Bra band elastic This elastic is plush on one side and smooth on the other. The plush side of course, makes wearing the bra comfortable. In general, larger size bras will use large widths of elastic. Since much of the support of a bra is in the band and cups (not straps!) then it makes sense to use elastic that is the correct size for the bra being made.
6+7+9+10 all together make up the bra band.
Many patterns have 7+9 as one piece.
The red line indicates the top edge of the bra, also called the neckline.
The blue line indicates where the underarm elastic is attached The underarm elastic, which continues on the back band toward the hook and eye closure is another plush back elastic, usually 3/8" in width, but for very large sizes, 1/2" might be more suitable.
I hope that this will help you if you are new to this type of sewing - it all seems a bit confusing at first because it is a whole new vocabulary and a whole new set of notions and fabrics. After a while, though, it gets easier, I promise.