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So I have a few broken rings of brittle spalted maple.



I matched them up and had thoughts of glueing them back together...then I thought it might be better to place into channel and glue instead
Think gluing in as pieces would be best.
Thoughts or experiences welcomed!

gregor

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With spalted wood, I would seal the rosette channel with some sort of sealer. I use shellac. Bulls eye SealCoat Dewaxed Shellac Sealer will work. As you suggest I would place the broken rings in the channel, I would then flood the rosette with thin CA. I have done this a few times with spalted wood rosette rings.

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I would probably do the same.

In the past, when using delicate spalted wood for rings I've usually flooded with super thin CA prior to cutting the rings...and if they seem like they might be particularly delicate, I've glued then to some thin backing material before cutting to help ensure that they don't break.

One thing to keep in mind with light wood and CA is that you most likely will end up with a dark line. I assume the joints between the pieces will be straight lines. If they are random then it will just look like more spalding. I would take a couple pieces of scrape and try the CA first.

Faint or no line?
Then I would seal the edges of the channel, not the bottom, (with de-waxed shellac) work the first piece into the channel and glue with the Medium CA and move around the rosette then flood with thin CA.

Glue line not so good?
Then I would glue a piece into the channel with a few dabs of medium CA (medium CA will give you a few moments to move things) but none on the ends, let it dry for several minutes. Put TB on the jointing surfaces, put a couple dabs of CA under the new piece and place it tightly against the first making a tight glue like. Let it dry some and proceed. After you have it all done and the TB has dried (about 2-3 days) then flood with thin CA

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Joe Beaver
Maker of Sawdust

I made a spalted maple rosette glued to 1/64" ply. I glued the rosette into the channel ply side down.
For an end grain olive rosette, I used 1/64" maple veneer for a backer, and glued it with the veneer on top, and sanded it off.

Alex

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

I've done the same as Alex and with the backer on top then sanded off the backer.
But before I became as smart as Alex, I would just glue the rosette back together. They always broke on a splat line so the glue line was invisible.

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Jim Watts
http://jameswattsguitars.com

CA and unprotected spruce is recipe for bad results. If u go this rout, be sure and seal channels with shellac. Glue pieces in channel. For this, I prefer Tite Bond original. Sand back after an hour.

With TB, there is a magical time where sanding will jam dust into any crevasses.

Believe me, smart and Alex rarely occupy the same sentence, Jim! I wrecked a few beautiful pieces of black line spalted maple to get one nice rosette. For another top, I wrecked a book matched end grain spalted maple rosette, followed by end grain olive wood rosettes X 2 before I put a decent one in a top.
Like someone here on the forum said...."clumsy yet persistent"!

Alex

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

Thanks guys.
Plenty of direction here for me. Im sure when it comes time to pop them in ill be successful...and if not, good thing i got a few more.
gregor

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Wake up and smell the rosewood!

This may be the most important post in this thread.

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Jim Watts
http://jameswattsguitars.com

We hear folks say "flood with CA" a lot and I really do hope that folks are not actually flooding with CA. Thin CA goes a long long way and you really only need a few drops along the edge, just so it seeps down into the cavity a bit. That's al that is needed when using CA. Too much and it will heat up and warp wood like you won't believe. Be very cautious with CA glues, again, a little goes a long way.

Apart from that, good advise with the titebond from Mike O.

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We've done a few buckeye burl rosettes lately for commissions, using the 1/64" ply back mentioned here as the base layer. After layout on the ply with compass, we mount the ply to an MDF carrier board with a full layer of double-sided fiberglass carpet tape - this gives us a nice, flat surface to glue up on and will carry the rosette through the thickness sander to surface. We use medium CA to glue the rough milled rosette material to the ply backing, making the joins in the darker areas of the wood or as mentioned, along natural dark spalt/color lines. A handful of dark dust from a scrap piece is useful for filling in areas where the join is not perfect.

Once the burl is glued to the plywood, we flood with thin CA, allow to dry, then thickness sand to 1/16". Using a 1/4" steel center pin, we mill the rosette to final dimension and separate it from the carrier board with naphtha. Once the ring is cleaned up with more naphtha, it is installed in the top channel, which is already milled to 1/16" depth. We mill the purfling channels, seal with three coats of super blonde or Platina shellac, and use thin CA to glue in place. The burl is once again flooded with CA and any areas which need a dust fill (lots of those little pits in buckeye burl) are handled with dust from scrap.

The first time I was walked through the process, I was very concerned about keeping the ply in the layup, but at about .017" thick, there's .040" or so of burl on top of it. Adding another 1/64" of depth to the rosette rout would not seem to me to materially alter the top stiffness in that area, so there's always the option to go to .075" on channel depth. The plywood certainly adds quite a bit of stiffness to the rosette ring, and makes handling much less of a concern.

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The longer I have been doing this the less I use CA. I do many wood and spalted rosettes.
They are simple to do. my favorite glue is Duco cement , this doesn't stain or add water to the top. My process is simple. I start making the rosette first. If the wood is really unstable I will glue this to a substrate like thin spruce or mahogany. I will plan for an opening under the fretboard it needed. Seldom will you make a perfect round wood rosette as the wood will often take a bit of an oblong because of the grain stresses.
Once the rosette is glued up and before I cut the rosette free I will make the first cut on the outside. Once this is established I will then follow that dimension to the top. Next cut will be the inside and then finish the channel on the top. To make the rosette complete I will after the glue sets run a .020 bit to split the joint and place a thin black ring to outline the rosette. Let the wood be the design and the purfling be the frame.
The duco is a good glue for the wood and sets up quickly . There are 2 reasons I no longer use CA. 1 it will stain spruce and 2 over time it will often show under the finish. It reacts to UV light different than finish. You can always find neat woods in the scrap pile to make unusual rosettes from.

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John Hall
blues creek guitars
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