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So, this morning before heading to work I went down to the basement shop to quickly visit the top I just finished installing the rosette in. Adi soundboard with a zip flex/black walnut/zip flex rosette. This is my second rosette. I believed everything went well. The rosette pieces fit tightly with no gaps; sealed the end-grain of the channel well with shellac; and installed the rosette with CA. Everything still looked fine. Into the drum sander to level; things still look fine. BUT, this morning I was feeling the rosette and noticed a place where the inner walnut ring sat lower than the zip flex. You cannot see what I am talking about in the picture, but I would say there is maybe a 1/32" dip in the walnut ring in the lower right 1/4 of the rosette. It appears the CA did not bond well in this area, and the walnut ring can be moved (i.e., it is not glued to the soundboard or the zip flex) in that area. I likely wasn't fully seated when I glued it in. I think I will have to take the ring out to fix this. Will CA debonder allow me to lift the whole walnut ring in one piece, or will I have to just rout it out? If I have to rout, I fear I will lose the very thin black purfling strip attached to the zip flex. This is a major downer. I thought I had it just right and was very happy with the results. Live and learn. Thanks.

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Aaron Craig

You should be able to wick in some thin ca to hold it all together.

There might be a few possible solutions.

If the top is not at final thickness you could possibly sand 1/32 off the whole top to bring everything level. You would want to make sure the rosette is securely glued in place so that you don't continue to push it into the channel.

Another option is to carefully rout through the back of the top until you hit the rosette channel. Then push the rosette level from the back and glue it in place. you can fill the routed channel in the back of the top with epoxy.

The way I now do my rosettes is to install them dry. I then mix up some thin wood glue (add a little water) and smear it over the top of the rosette. This seeps in a little and when dry holds everything in place. I then rout a channel the same width as my rosette through the back of the top. I set the router so that it just skims the back of the rosette. I then fill the whole channel with epoxy and let it dry. Then I do the final levelling of the rosette from the front of the top. I glue a wooden patch on the inside of the top to reinforce the sound hole area. This totally covers the channel filled with epoxy so that it is never seen.

Hope some of that is helpful.

Josh

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

I could wick in some CA to hold it together, but I'm not sure that fixes the problem. I probably did a poor job explaining the actual problem. There is not a gap between the zipflex and the walnut ring. Things are still tight. The problem is that the walnut ring was not pressed fully to the bottom of the soundboard when the rosette was sanded level. Now that the ring is loose and can fully seated to the bottom, there is a dip or low spot in the walnut ring (i.e., this portion of the ring is not level with the rest of the soundboard). The top is near final thickness, so not much more room to bring the rest of the top down to the thickness of the low spot. I could probably take off a couple more thousandths, but I don't think it would be enough. I could wick CA into the ring while it is setting near level with the board, but that would cause there to be a small gap under the ring in this location. I would think this could cause problems in the future, but I'm a newbie so what do I know.

_________________
Aaron Craig

As a side note, I used to use CA but eventually gave it up after having it stain several tops. I only ran into trouble on Englmann and Red Spruce but the result was a glowing yellow/green stain that often only showed up after the finish was on. It was frustrating, especially since I had sealed the channel with shellac. The worst trouble was when using woods like Cocobolo or Brazilian (oily woods) for the rosettes. Since switching to the method I mentioned above I've been able to use any type of rosette in any type of top with no issues whatsoever.

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Thanks for the advice Josh. Routing from the back might be a good fix, and, at least to me, seems more preferable to routing out the ring. Like I said, I am quite happy with the look of the rosette, and I don't want to mess it up. How thick do you make the patch for the underside? Also, do you take the patch all the way to the soundhole, or do you stop it a bit after the channel you have made?

_________________
Aaron Craig

As a side note, I used to use CA but eventually gave it up after having it stain several tops. I only ran into trouble on Englmann and Red Spruce but the result was a glowing yellow/green stain that often only showed up after the finish was on. It was frustrating, especially since I had sealed the channel with shellac. The worst trouble was when using woods like Cocobolo or Brazilian (oily woods) for the rosettes. Since switching to the method I mentioned above I've been able to use any type of rosette in any type of top with no issues whatsoever.

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

I did exactly what you are describing on my rosette this past week. This is my second rosette so I'm sort of winging it here.

I basically did this.


I drilled some small holes (just spinning the bit in my fingertips) and pushed the rosette ring flush with the top. I then packed in some epoxy to fill the gap.


Before I could push this small section of the rosette with my fingers and feel it give. Everything feels solid now and is level with the top.


If the drill method didn't work I was going to route a small section to expose the gap between the wood and sound board. But I think what I did will be effective. Just be careful not to make what you do visible outside of the rosette area.

I hadn't sealed with shellac so I wanted to be careful of issues with CA staining the top. Actually I'm not sure if I should have been worried about that with Epoxy. I think CA might have been easier then packing the epoxy if I had been prepared for it.

Thanks to all. Last night I used Todd's method of pushing the rosette up with a small, sharp needle from the backside to level and wicking in CA. A bit of fine scraping and a few strokes with some 220 grit, and all seems golden. Thanks again.

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Aaron Craig