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Just for additional info to consider, the sequence I use for a rosette design like yours is:

- Make the wood ring to be inlaid into the top by routing it out of a plate.
- Route a channel in the top a few thousandths wider than the wood ring and glue the ring into it.
- Route channels on either side of the inlaid wood ring for the purfling. These channels are slightly wider than the total width of the purfling. "Slightly" means that the purfling fits in the channel without any pressure and with a gap on one side that is just barley visible to allow for swelling with the glue (LMI glue in my case). After you do this a couple times, you get a feel for how wide "slightly wider" is and it can be done reproducibly.
- Put a bead of glue in the bottom of the channel and push it into the bottom corners of the channel with a toothpick. If more than one piece of purfling is going into the channel, I wipe the surface of one of them with glue so that there is glue between the purfling pieces. Install the purfling.

I don't use CA to inlay a rosette of that design because if I'm not using CA I don't have to worry about it staining the top. Since I don't shellac the top before routing channels, I also don't want to add an extra step to the process by having to shellac the top to contain the CA. I don't find the swelling of the purfling to be a problem. In fact, it's something that can be taken advantage of to get a nice tight fit. No stress. Here's a similar rosette I made a few weeks ago.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Nice clean work, Jay. That's the way that I did my one and only rosette. Inlay the ring, and just touch it with the bit at the purfling line.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

OK -- perhaps time for a recap, unfortunately I think sometimes these "need tips" posts evolve into "this is my method" or favorite method response.

Most any adhesive can be and has been used to install rosettes PVA, solvent (Duco) and CA etc. all will hold the inlay in place for the life of the instrument. So the issue is selecting a product that will not lead to known negative consequences.

I believe the OP was regarding a tight fitting rosette -- we know that water based adhesives can swell the soft wood channels so it is obvious that it not a good idea to unnecessarily complicate the installation process. No problem, we have simple options, first being Duco or one of the other (like Testers) solvent based glues. and the other choice CA -- but as indicated the channels and surrounding area need to be sealed to prevent wicking. Like the factories I prefer clear lacquer because it does not tint the wood, others use shellac. I am not sure why using PVA would be the only option but the suggestion of applying a thin glue layer to the individual pieces would certainly minimize the chance of swelling but seems a little tedious to me.

On the end of the spectrum is the under-size rosette -- for this most times its best to add an extra thin black .010 line --- if that will not fit its likely that PVA glue will puff up the wood enough to make a tight fit. The "extended" work time versions of PVA have more water -- so more swelling.

I don't think this needs to be a debate of what adhesive is best for installing rosettes -- its merely addressing the issues and weighing in on the options.

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Ken Cierp

http://www.kennethmichaelguitars.com/