George (GBF, that is): we worked exclusively with stains, which work very differently from dyes. Stains are are pigment particles suspended in a carrier. They tend to penetrate much less deep than dyes, which are pigments dissolved in the carrier (i.e. no particles, the solution goes down to molecular level).
I have tried the method of covering the end grain with wax or sanding sealer, and it does work to some degree (better on stains than on dyes), but proper dyes have a habit of going quite deep, obviously depending on the type of wood used. Maple is better than others, as it can be quite dense, and the dyes will only travel about 1-3mm.
Having said that, on occasion I had dyes go completely through from the outside of a box to the inside, more than 5mm. When that happens, clean lines as in your bowl above become very difficult to achieve.
