Sinamay is a relatively new material that is becoming increasingly popular because, unlike the other established millinery materials such as straws and felts, sinamay is light, flexible and easy to use. If you are skilled enough, you don't even have to block sinamay; you can just craft it with your hands.
Cut the sinamay material to exactly 1.82 metres (2 yards). Fold the material over so 91 cm (1 yard) rests directly on the other section.
Dip the sinamay into hot water quickly to soften it and allow a few seconds to drip without allowing to dry. If using a steamer, steam material until soft, limp and pliable.
Drape the soft sinamay over the hat block and begin to pull to remove all creases.
Use your upper body to hold the sinamay in place while you use your hands to pull and fold material under the block and pin. Pin all around the block, pulling all the time to remove creases, leaving at most 2.5 cm (1 inch) between pins. If using a wooden hat block with a groove, tie white cord in the groove tightly. Since sinamay is not in a hood form, you will have lots of folds at the base of your wooden block. It is not necessary to remove these creases; they will be covered when dressing the hat.
Place the wooden block in an oven, preheated at 120 degrees C (250F), for six to eight minutes. When the sinamay material is dry, it will mould to your block perfectly.
Spray millinery sizing on the hat in a ventilated area while the hat is still on the block. Allow 10 to 15 minutes to dry. This sizing will help the hat maintain its shape through many wears.
Remove the sinamay hat from the block by using the bone from a corset. Gently push between the hat and block until loose, then lift the hat off the block, being careful not to distort the shape.
Cut away the excess fabric from the hat, leaving 2.5 cm (1 inch) of excess to use in finishing the hat.
Measure the millinery wire to fit your head or the head of the person who will be wearing the hat. Cut the wire, allowing 2.5 cm (1 inch) for the wire joiner.
Push the wire joiner on to one end of the wire and insert the other end of the wire into the wire joiner. Use pliers to close down both ends of the wire joiner.
Insert wire into the fold at the bottom of the hat and reinforce the fold by pushing it up against the inside of the hat all the way around.
Use the same measurement as the wire to cut the grosgrain ribbon. Sew this ribbon on to the excess of material that is now folded inside the hat using the back stitch. The grosgrain ribbon is now what is called the sweat band of the hat.
Fold the top of the rectangle halfway down by width and fold the bottom of the rectangle halfway up to meet the other fold. Iron on the ironing board to secure folds and to give a finished look. This hat band will be wrapped around the base of the hat so folds are not visible anymore. Sew to keep the ends in place.
Hot glue the flower over the ends of the hat band to finish your sinamay hat.
When your sinamay hat is finished, you can add veiling, rhinestones or whatever you like to make your hat more appealing.
Double the sinamay material or the finished hat may be too transparent.