
Flat steel boning
Flat steel boning is made from sprung steel - it does not buckle when you bend it (unless you bend it very hard obviously). If you bend flat spring steel you will take the spring out of it and it then will not work properly.
Spiral wire boning for corsetry is made from two metal springs flattened and wedged together! It is very flexible and makes a sharper nip at the waist than flat steels. Different types of bones and different combinations of boning have different effects in corsetry.
Most plastic boning is made from polyester and is good for stiffening bodices, dresses, gowns, lingerie and swimwear.