Some binding / rosette questions

[Coach]

I'm planning to do a couple more builds in wintertime. I haven't used bindings nor rosettes in my previous builds, but plan on doing so now. So, I don't intend to use any purfling at all, just straight wood. That goes for both the binding and rosette. I do have a few questions:

1) Other than aestethics, is there a meaningful purpose for purfling? Will I be fine without it?
2) For the rosette, will using say a straight walnut without purfling pose any issues? Can differing extension rates cause cracking?
3) In low humidity, can the fret ends cause the wood bindings to seperate from the fingerboard?

[tippie53]

Purfling is a declarative adornment .

On the rosette you may want to use an edging.
viewtopic.php?f=5&t=5295&hilit=+rosette

Fret ends can push the binding out so you want to trim the tangs back a bit so that doesn't happen.

[Coach]

Would the rosette edging serve a purpose other than aesthetics?

I did forget to ask about wood inlaying on the fingerboard. How do I find out what woods have similar expansion rates as rosewood? Once I put in a lot of time into inlaying, I wouldn't want the fingerboard to deloped cracks.

[B. Howard]

What are you thinking for the FB inlays? Dots, diamonds, blocks? Something like dots will not matter as much. The ones I see split usually have large block inlays. The expansion happens as a percentage of the size, so the larger the piece the more it will move. Another consideration may be hardness of the inlay wood and weather you will be finishing the FB or not. Hard Maple is fairly stable, but would need finished or it will discolor. Mahogany is very stable, comparable to a rosewood, but may be a bit soft for a FB and would like finish as well. Oaks are not so stable, white is worse than red.Information on this is scarce but tables do exist to aid cabinetmakers in proper panel sizing for 5 piece fronts.

[gsr]

In my first few builds I used simple binding with no purfling. It is fine if your ledges are very clean and straight. Others my disagree, but I have found the black line in purflings to add just the tiniest amount of forgiveness. Glen

[Coach]

Another question: when do you route the rosette groove? I'm thinking I'll sand the top down to around .150 inch, then route the groove, glue in the rosette, then sand the whole everything down to final thickness.

[tippie53]

I like to just surface the tops so the top show and hidden side are surfaced . Then as the top is at the thickest possible I do the rosette , that way I have some fudge room if I need it.
You should be fine

[Coach]

If the rosette is installed and final sanding is done, will the darker wood of the rosette stain the lighter colored top?

[Kevin Sjostrand]

Hey Coach.
If your top is spruce, it is not porous and should not be an issue. However, if you are still concerned, get some spray can shellac and spray your rosette and surrounding area to seal it before doing a final sanding. I don't think you will find that any wood dust gets into the spruce. Also, make sure to do your final thicknessing of your top on the back side if you are putting your rosette in with your top at .150" after leveling your rosette.

Kevin

[sylvan]

Shellac where you intend to cut the rosette. This will make the cut(s) crisper and will seal the wood and help to prevent any bleed through from the darker woods.