I spent a great deal of time (too much time) trying to decide just what my soundhole rosette should look like. I really wanted a little bit of abalone, but I was also aware of the costs and caveats associated with working with abalone inlays. Finally I decided on an abalone inlay with two concentric rings of rosewood (cut from the left over back material) around it, and of course some of the BWB (black/white/black) purfling strips. I also used AutoCAD to help me visualize and measure for the rosette channel that I would need to cut into my soundboard.
I borrowed a friend's bending iron (you can make one) to bend the purflings and the rosewood strips cut from the back material.
The rosewood was a little thicker (.11") than the ideal thickness of .09", so bending was extremely touchy--after snapping a few practice pieces, I finally tried misting the wood with water and wrapping in foil, then working it slowly over the bending iron. The aluminum foil served to trap in the steam--the key to successful bending--and after a night drying while clamped into a circlular form in some plywood, I had nearly round rings. By the time all the strips are "seated" in the soundboard routed channel, they all work together to tighten up and make a perfect circle.
At this point in the building process, the idea of having to rout a perfect circle of a perfect width out of my soundboard was a little intimidating--there's really no room for error here. The book talks about dry fitting the purflings and inlays and then pulling it all out and glueing it all in again with wood glue in one swift step. Instead, it was recommended to me to take my time fitting all the strips, and then covering the top with a watery super glue, allowing the glue to "wick" down among the strips. That way I would be sure the purflings aligned properly. This actually worked brilliantly, and I can't imagine the hassle of using wood glue for this step (it took me hours to fit all the strips in properly).
Lastly I spent a little while planing down the rough rosewood to approximately the soundboard level, and then finished it off with a scraper (leaving just a microscopic amount for "final sanding").
