Pop up sun hat

i want to make my sister in law’s pop up sun hats for Christmas.
i saw the idea in tsarina’s blog. she has no pattern to speak of really but im gonna try to make these hats based on pictures.

a couple of questions tho…
how long should the “tube” be.
would ribbing or ribbon work better for fit purposes?
im kinda leaning twards ribbing for a no hassle feature. what do yall think?
how would i encase the pop up wire? meaning sizing it to the hat dimentions, and does it need to be encased before adding it to the hat?

or shoot… if someone has a pattern already for this hat…please send it to me. or let me know where it is.

as for now, i will be casting on for hat number one and taking pleanty of notes.Crossed Fingers and checking back here for some help.:frog:

http://www.mydiscountwholesaler.com/popup-collasible-portable-trash-can-p-1907.html
She says she used the wire out of a pop up trashcan, like this one. She found her’s at the dollar store, I’ve seen them at Walmart for a couple bucks more then that. Encased in muslin - probably to keep the ends from poking you.

For the hat, you’d want something this shape: this one is crochet, but the sort of shape you want: http://www.vogueknitting.com/patterns/free/2008/floppy-brim-hat.pdf
Here’s a knit one that would work:
http://www.amazon.com/gp/feature.html/ref=pe_35010_12282320_fe_txt_2/?docId=1000387361

http://birchstreetclothing.com/group.php?itemID=9010&colID=4
I made this one years ago, it’s fabric not knit. But the company sells hat wire specifically for pop up hats.