There are two things you will most likely want to do with petersham. First use it to edge the brim of your hat the second is use it as a hatband or sweatband. The most important thing you need to know about petersham compared to grosgrain ribbon is that petersham can be shaped as the edge is not fused. So while you could use regular grosgrain ribbon could be used for a hatband or sweatband on a hat with a 90° straight up crown you can not shape it to be used on an angled crowned. The examples below show the type or hat you can and can’t use regular grosgrain ribbon on (these are both real petersham).
No- crown is at an angle.
How to shape petersham for the edge of a brim.
This is the same hat as above and even though it is straw and really does not need an edge with ribbon I wanted to cover the wire I sewed to the edge for extra support. Below are the steps needed to get the “U” shape in your petersham. The best width for brim edging petersham is the ~1″ wide.
In order to do this you need something with a rounded edge. A dinner plate can work but I used this colander an advantage is it stands by itself. It’s a good idea for it to be about the same diameter as your brim. For large hats I use the edge of my canning pot. Tape/clip the edge of your petersham to the colander half way over the edge.
Steam a section of the ribbon do not touch it with the iron this will cause it to turn shiny.
Stretch it around the colander until the center stretches and the ribbon forms to the edge of the colander.
Steam another section.
Pull/stretch some more. Continue until you reach the start. Tape that down.
Adjust the ribbon adding more steam if necessary until it is even all along the edge. Let it cool then you can take it off the colander.
Shaping ribbon to fit an angled crown.
Shaping sweatbands and hatbands: If you steam and stretch it you can get it to arc. This is important, when using petersham as a hatband or sweatband on hats where the crown either gets smaller or larger towards the tip, such as the Elizabethan tall hat.
To shape a petersham hatband I lay the pattern piece as a guide on the ironing board. Steam the ribbon and stretch to form it while warm. It is important not to touch the iron to the ribbon as this will bring out a shine. Modern petersham is a rayon and cotton blend and unlike vintage petersham ribbon it is more sensitive to this problem.
There are some hats either because of the angle or the width of your petersham where you can’t get the petersham to arc enough. In that case I often especially with Victorian tall hats use multiple layers of petersham and start very hight on one side and then bring it down to a “V” on the other side, as with this tile angle crown hat. This hat not only has a crown that angles towards the crown tip but the base of the crown is not level it’s high on the side that the brim is wide on.