Re: hand made hakama
. . . and this is Carol, who's revised a lot since Day 1 hakama pattern, thanks to Janet and Jill and others. ;-)
Folks, don't panic over making a hakama. It's really just a double-barreled apron with legs. But here are some issues to consider whether you make or buy. . .
Pleats. Don't expect cotton to hold a pleat. It may hold a wrinkle, but pleats are something else again. Look for a cotton / poly blend.
With at least 10% polyester and a white vinegar solution you can produce an excellent home version of permanent press, AND have a lighter weight, cooler, and longer-lasting hakama to boot.
Failing that, don't hesitate to stitch down the internal ("valley") pleats. Traditional Japanese textiles were only 12-14" wide, hence a hakama was pieced from a series of panels and those inside "pleats" were actually SEAMS. No danger of those falling out, and reduces the challenge of folding pleats by about half. Also useful for skinnying down the bulk of fabric if your hakama is too big and too floppy.
"Lighter" is important because layers of pleats -- there are 7 layers at center front due to the overlap. 7 layers of canvas or heavy denim can be tough for many home sewing machines. If you prefer a heavier hakama, better to buy it commercially made. Many prefer the way the heavier fabric flares and billows rather than tangling up in the legs. TOO LIGHT a fabric will trip you up for sure.
"Cooler" -- many of us have bought hakama of 16 oz cotton duck on the theory that the heavy weight will last longer and yet be cooler because "cotton breathes." Great in theory, but "duck" was originally packing and awning canvas. Fibers swell when exposed to moisture making a somewhat water resistent seal. Great for awnings. Not great for wrapping around bodies in August in Atlanta. And the knees will wear out anyway -- because of the cotton.
"Stronger" -- No matter how heavy and hot and bulky a cotton hakama you buy, the knees will still wear out. Most cotton fibers are about 3/4 inch long compared to the yards-long fibers of silk or hemp, or the miles-long fibers of spun polyester. Cotton is wonderful stuff, cool and absorbent, etc., etc., but resisting abrasion is not its strong point. One of the reasons the all-polyester Tetron hakama are so popular is that the pleats are melted into place, they're lightweight AND they don't wear in the knees. Look for a good blend and you can have the best of both worlds.
Koshiita: Some of you have recommended plumber's gasket, bedpans, mousepads. I've been told of recycled X-ray film, placemats, notebook covers, bathmats, and leather from an old briefcase. Whatever works! The Japanese traditionally used starched paper or newspaper. Open a Mejii-era koshiita and you may find a Mejii-era newspaper with interesting news of the day.
Per bathroom breaks -- rather than velcro, or snaps, or whatever, consider using a deeper crotch than what you expect in jeans. Hakama was worn over kimono and the crotch might be knee length or longer. The hand-made Mejii-era hakama that I used as a model has its "crotch" just a couple inches above the hem. Traditionally the side slits matched the depth of the crotch.
You probably won't want to be all that traditional, but several extra inches of depth with a pair of stretchy knit gym shorts can completely eliminate any need to get undressed and dressed again in the middle of class.
You don't have to make your hakama to get these advantages -- you can choose one of polycotton (rather than industrial-weight cotton canvas) and permanent-press the pleats with white vinegar, you can stitch down the inside ("valley") pleats (use a zig-zag stitch along the edge to avoid puckering), and if the rise is too high, just cut it lower. (Of course, if you want the Gordon Plaid hakama, or the red Inuyasha one, you'll just have to make your own!)