Official Luthiers Forum!

I am about to try making/installing a rosette. It will be one continuous ring consisting of bwb-zipflex-bwb-Koa-bwb-zipflex-bwb. From reading some of the other threads here it seems there’s support for installing the wood ring first, then working outwards and inwards from there. My question is how to proceed after installing the wood ring, since the bwb purfling and zipflex have different depths (.080 and .055, respectively). Is it better to work progressively-- i.e. cut one channel (~.080), install the purfling, then cut the next channel (~.055) for the zipflex and install it, then cut the last purfling channel and install it—or just cut one channel at a depth appropriate for the zipflex, install all three pieces, then scrape off the excess bwb?

Any advice would be appreciated.

John

I would just cut one channel a few thou shallower than zip flex.
Do a test run in a piece of scrap to get the fit right. If you are not using CA, remember to make the channel a little sloppy. It'll drive you nuts when everything starts to swell while you're trying to squeeze all those strips into the channel.
If you are using CA, don't forget to seal the channel first to prevent yellow stains in your top.

I would inlay everything into the middle of the Koa, and leave off the wbw. Then cut the outside of the koa rosette, then the inside of the koa rosette. Then cut your rosette channel in your top, and creep up on the wbw on the outside and inside. That's how I would do it. It may not be correct, but it should work just fine.

_________________
Tracy
http://www.luthiersuppliers.com

Here is how I do that ...

Cut and inlay the koa ring alone ... take into acct the width that you will be inlaying around it, ie, your lines and shell. You dont want to find out you have to route away too much of your ring to get a 4 inch soundhole once the shell and lines are put in. Draw it out on paper even, and make the koa ring a 1/6 bigger on both sides. So -inlay the ring, proud, then sand the top back so its level again. reseal with shellac or FP ....

Now that the ring is glued in and dry, cut the channel for the lines and shell, starting from the koa and working out (or in on the inside to the soundhle) - if you are using something like the Karol rosette jig, you can creep up on the actual width, checking the fit as you go - I route this all the depth of the shell, maybe a touch more. Once the fit is snug, but not tight (the lines and shell should stay in, but easily come back out), I reseal the channel with FP, and then push the lines/shell back in. Fit the ends. Flood with CA. Sand back flush. You are officially done !!!

_________________
Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Gotta love that Karol rosette jig! I have two!!!

_________________
I'd like to be able to prove, just for once, that money wouldn't make me happy...

Ha, I made that exact rosette a few months ago and it was kind of a pain. The problem I had was the scarf joints on the bwb purfling (I used ABS plastic). What I did was cut a single scarf then expected the plastic to bend out - it didn't work so great and I had to fix some flubs. Next time, I'll cut a scarf on both sides. I also glued the ends of the BWB purfling together to make it easier to handle.

Definitely inlay the koa first, then cut slot's on both sides. No need to go one at a time for the various layers. Go slowly though and have your purfling/zipflex handy to test. You might need to make minor adjustments.

Attached is a finished shot and an in progress shot. If you look carefully at the finished shot you can see the repairs.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Oh, and as to channel depth, obviously I did mine all at the same depth. There were a couple spots where one of the B's or W's lifted too much but I think I just wasn't paying close enough attention. Next time I might try pre-glued wooden or fiber purflings though.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Try back wrapping a couple pieces of some painters tape around the lines and slide them as you put the lines in. It helps to keep them orderly.

Thanks for all the good advice. This is what I ended up with.

John

Nice! I'm curious, what adhesive did you use?

I recently did a similar rosette and had some issues with the zipflex not liking the LMI adhesive (it didn't adhere well). I ended up having to go back over the zipflex with CA to fill in the channels and get a good bond.

_________________
Jim Hansen

I used LMI white, but didn't notice any adhesion problems. Having read your post, however, I think I'll check if the shell is at all loose (probably easiest to check the area that will be under the fb extension). If it is, I guess I can seal the spruce with shellac and flood some thin CA over the rosette.

John