I've dug this one back up because I'm experimenting with a couple of styles at present.
I think one of the main problems (aside from wind) on a sandy site is that you need to create a lip that holds the sand in the bunker. If the site has little organic topsoil and therefore is pure sand just under the surface, you cannot create that lip easily without it just crumbling away unless you hold it with rough grasses.
This leaves you with a few options. Personally I like to leave the face natural and rough edged with long grasses on the side that backs in to the rough but for green side bunkers, centreline bunkers and the near-side of other bunkers that I want to be mown as fairway right up to the edge, it is harder to get a finish unless you use / transplant / sprig rough grasses on to the face… In other words, without using sod walls at least in places (and these can be mixed with sand faces but then just stacked two or three high to create a lip), I think it is hard to create a bunker face that transitions straight from short grass to sand. And I like that. I like the rough, natural faces as well but not as islands surrounded by short grass on all sides.
Thoughts? I could do with hearing other experiences, especially with lip creation on pure sand sites…
Thanks,
Ally