Before I get into corset assembly methods, I need to talk a bit about materials.
If you're going to the trouble to make your own corset, don't waste your time by using anything but steel boning. I've talked elsewhere about the evils of plastic corset boning, but let's just say steel is more comfortable, works and looks better, and lasts longer. The majority of corsets are made with solid flat steel bones at the back and front (i.e. the busk), with spiral steel bones everywhere else. The spiral steel bones are made up of steel wires and are very flexible. They can bend in any direction and will spring back to their previous shape.
The flat steels don't bend from side to side, but do flex in and out.
They can also be permanently bent either intentionally or unintentionally. Some corsetmakers prefer to use all flat steels to get more rigidity or because they feel it helps get more reduction in the waist. But the majority use spiral steel for comfort and because it can be placed along curved seams.
The most economical way to buy spiral bones is by the yard on a roll. You CAN buy them pre-cut and tipped, but it's WAY more expensive, plus if you make changes to your design on the fly, you may have to cut them anyway. But to cut the bones you will need a special tool, or steel cable cutters. (Make sure they are made for cutting steel. I bought some that looked great, but weren't for steel. The bones chewed them up.) You will also need to either attach special steel tips to the ends to make them round and smooth. These tips are notoriously difficult to get on unless you have a special press. One friend uses E-6000 to glue them on, which I might try. But I gave up on these fiddly things a while back and now I just use plumber's thread tape to wrap the ends. It doesn't have adhesive to gum up your corset and only sticks to itself. You can wrap as much as you want around, and it's CHEAP AS HELL. Plus, instant boning gratification. I just cut each bone as I sew its channel, wrap with tape, and insert. No pliers, no waiting for stuff to dry.
So I told you not to use plastic boning, and I meant it, but if you ABSOLUTELY HAVE to use plastic, because you need your corset tomorrow and can't wait to order steel boning online, don't go to the fabric store. Go to the hardware store and buy heavy-duty cable ties. They are stronger than any plastic boning sold for the purpose and they won't warp as easily as most of the stuff. I use it for mock-ups and for boning in places that aren't under stress, like a boned modesty panel.
There are three main types of fabric used in a corset, determined by their purpose: fashion fabric, strength fabric, and lining fabric.
Fashion fabric is the fabric that will show on the outside. It's the pretty stuff. This can pretty much be anything, but some fabrics are going to be easier to work with than others. I would avoid any fabric that is very lightweight at first, as it will be more difficult to make look smooth. But silks are popular choices, and since a corset really only requires about a yard of fabric, you can splurge on the nice stuff. I'm personally a big fan of using poly brocades. The thickness is nice, and I melt the edges of all my cut pieces with a candle to prevent any fraying. If you are using thin fabric, you may want to fuse it to your strength fabric using fusible web. Alternately you can flat-line your fashion pieces to your strength layer by sewing around the edges of each cut pattern piece. It makes the corset assembly easier later.
Strength fabric is usually one of two types of fabric: coutil or cotton duck. Coutil is the traditional fabric made specifically for corsetry. It is typically cotton, very densely woven into a herringbone pattern. The reason it is perfect for corsets is that it has NO stretch at all in any direction. It is the toughest fabric I've ever seen, but is also pretty lightweight and smooth. There is domestic (US) coutil and imported coutil. Imported has a higher thread count and is denser and therefore more expensive. The only downside to coutil is that it is difficult to find and it is pricey. It runs at least $20/yard, often more.
I've used it and though it's nice, generally I go for cotton duck for price reasons. However, if you're going to make a corset for everyday wear, I do recommend coutil. I have a corset I wear everyday made from cotton duck and after about six months, bones are starting to poke through and wear through. I'll be making another one from coutil.
Most people are familiar with cotton duck, though they may call it canvas. It's available in every fabric store in a range of colors and prints. The only thing to watch out for is to be careful not to buy any duck or canvas made for outdoor use. This is treated with a water-repellant chemical and you DON'T want to use this in a corset. It won't breathe at all and won't absorb sweat. Usually it's easy to avoid this stuff, but especially if you're buying a remnant be careful what you're getting. I buy all my duck in remnants. It doesn't matter what color or pattern it has, since no one will see it. (Unless it's your outside fabric also.)
For lining fabric, I recommend either cotton twill (if you want something sturdy, that can also act as a secondary strength fabric), or plain 100% cotton quilting fabric. Don't use the thin poly lining fabrics, they don't breathe and aren't strong enough. The only consideration otherwise is that due to twill's diagonal grain, you need to alternate the direction you cut your pieces in to prevent it from pulling strangely. Overall, I like quilting cotton. You can even use some really funky or silly print, since only you are going to see it.
You will need a busk for the front closure of your corset, grommets for the lacing holes, laces, and ribbon, bias tape, or self-fabric bias for the binding. There are alternatives to most of these, but these are the typical supplies needed.
This illustration shows different styles of busks. Generally, you will use a straight busk, unless you're recreating a historical corset that used some other style. There are different strengths of busks and often it depends on where you buy them. A heavy-duty busk will hardly bend at all, which can be what you want or it can remove some of the curves from the shape of your corset. But too flimsy of a bust may be really difficult to close, and may cause other fit problems. Unfortunately, I haven't really learned a way to predict what kind of busk I'm getting, except by trial and error and learning which distributors I like.
Where to Buy:
Speaking of which, let's talk about where to buy supplies. Unless you live in New York, LA, London, or Paris, it's unlikely there is a corset supply store in your town. So the internet is your friend. There are several corset supply websites, but I don't have experience with all of them.
Corsetmaking.com - This store has pretty much everything you might ever need to make a corset. I've bought from them most often. Their standard busks are a little flimsy, their heavy bones are REALLY thick, and I love their boning cutter. Also, they have nice grommet colors like antique silver and antique gold.
Dragontown Corset Supply- I really like their busks. They are a nice middle-of-the-road option.
Faire Lady Designs on Ebay - I really like this shop, and she has some great prices on spiral steel boning. But her corsetmaking stock is thinner than it used to be. Good quality clothes, though, FYI.
Farthingale's - I've never ordered from them, but they have some difficult to find items, like lacing d-rings. They also have an LA store.
Vena Cava - A UK site, but the only place that sells swing hooks and drilled bones for a swing hook closure. (Which I'm going to have to order soon, note to self.)
Ok, so I HOPE that's all the info I needed to get out prior to my NEXT post on corset assembly.