Don Noon

Glue sizing the joint surface probably helps, but there is still an expansion problem with putting hot, wet glue on figured maple. The expansion longitudinally is the primary problem which bends the wedges and makes the gluing surface convex, with increased gap at the ends. It is more of an issue with figured maple, where the grain is not 100% along the joint, but some tangential grain is involved, which increases the expansion/contraction longitudinally. Spruce is almost always straight grain along the joint, and I haven't seen end gapping issues with it. That's a potential glue joint uniformity issue; then there's the later environmental heat/humidity variations tending to pull the ends apart. If the humidity changes slowly enough, everything should move uniformly. If the humidity drops more rapidly, the endgrain would dry out and cause gapping at the ends, but also if the wedges are left uncarved, the outside edges will dry/shrink faster, also tending to cause end gaps. There are a few ways to combat all of this. Make the sufaces slightly concave, so that the small amount of expansion/bowing during gluing will make the joint more flat. Paint some hot water on the outer edges of the plate (opposite the glue joint) to counteract the bowing Cut out notches where the C-bouts will be to lower the stiffness of the wedges, and clamp at the ends (and the middle too)... see photo. You might want to rough the outline and graduations as soon as possible to lower the forces tending to separate the joint during weather changes. Then there's the gluing issues. Stronger glue sounds good. Gluing in a hot room to assure the glue remains liquid, yeah, that too.

Although not directly related to violins in any way, that is a fantastic documentary... especially for engineer nerds.

Is there any history on other good makers who have died, and how valuations trended over time after their death?

Yes, VSA (or other vendor-attended conferences) and IV. Where do you windsurf? There aren't too many of us left using the old stuff, now that wingfoiling has taken over.

I haven't tried brown paint, but that seems like it would produce a burned flame; not the results I'm looking for. What I have tried is a light application of tung oil, wiped off as completely as possible, and then dried well. Some oil remains in the wood to enhance chatoyance, but not enough on the surface to create gloss and friction. Tung I think is more waterproof than linseed and shouldn't get sticky. I remember one violin (not mine) where the neck was treated with linseed, and it was like glue.

Also on that page, to the right, you can find: The auction record for this maker is $25,200 in Mar 2025, for a Cello. Then, if you log in for the auction history, you can find $19,200 last year is the highest auction price for a violin. Perhaps Matsuda is trending lately?

There are more expert evaluators than me, but they don't seem to be jumping in. I'd say that the wood was decent (figured back, ebony? fingerboard, even grain top), construction mediocre-ish, and currently in very rough shape. If I had it, I'd dump it on eBay for whatever it could get. Unless it sounded good, then I'd keep it as a camping fiddle.

If your preference is the latter, then do that. I consider myself a mostly self-taught amateur maker. Yes, I have taken a few workshops in making and acoustics, visited a few decent makers to leech their methods for a few days, and attended VSA and other violinmaking competitions. But by far the vast amount of learning has been from actually doing the work. It looks like you are far ahead of where I was in the early days. When I had a full-time job, I was hesitant to tackle making a violin from scratch, so I just messed around fixing up worthless old beaters or cheap student fiddles. It was only after I retired that I made my first violin. As I learned more, I became dissatisfied with my previous work, and almost all of the early ones have been apart and modified at least once, and many have been revarnished... sometimes 2 or 3 times. I am currently in the middle of work on #34, but I have taken time out to modify and revarnish #2 according to my latest ideas... both to test the new ideas out, and regain what skills I may have lost in the 3 years of inactivity due to some medical issues and some mental burn-out. This is a long-winded way of saying "do what you want to do", and also that almost anything you do now can be fixed later, if it's needed.

https://www.strad3d.org/music.html Kavakos seems to think the Willemotte is pretty good. Titian and Plowden don't seem to have the same fame, but I can't say much beyon that. The latter two are smaller models. I wouldn't want to have surgery where the surgeon downloaded an image of my brain from the internet that was taken by someone else and tried to figure out where to cut by scaling it

Getting back to the original question... I wouldn't put much faith in CT scan images where there is no assurance of the level of accuracy. And certainly scaling thicknesses to some semi-arbitrary scale won't tell you anything more. Much better to use actual graduation maps from reliable sources. Looking at CT scans for general shape and concept might be useful, though. In the area in question, immediately above the F holes, I don't think it's all that strange to see a thin center and thick at the edges. For example, the Titian goes from 2.2 minimum in the center to 3.1. I wouldn't obsess over this.

Whether you like the look or not, knots are severe disturbances and discontinuities in the grain that can cause problems, such as becoming detached and falling out. Expansion and contraction with weather or over time will be different for the knot vs. the surrounding wood. Sure, they CAN be OK, or be glued back in if they loosen... but as a maker, avoiding these issues is easy by getting another piece of wood. I'm not a knot fan, particularly for large ones like these:

That's a big knot. Assuming the maker started with wedges, it would be out at the thin end where I'd find it hard to believe it would be hidden before carving. Only the maker could say what is thinking and aesthetic decisions were; no way I'd use it. Maybe I'd cut that edge off and splice on a wing.

About the only answer I have is: yes, that's a test sample the aluminum/zinc rosinate of alizarin that I made. For all the other questions, I don't know... the test sample is as far as I've gotten with this stuff, and haven't actually varnished an instrument with it. Hopefully I can mix it in with a fairly sweat-proof varnish without it going purple.

Yeah, I have spent plenty of time messing with varnishes, mostly seemingly failures except for gaining knowledge. Up until now, I have avoided this thread, knowing it could be a huge time sink. However, I had a fair bit of experimentation with Michelman rosinates that might be useful. I particularly wanted to get a very concentrated color that I could mix in with other varnishes. The alizarin "resin J" (on page 152 of the Michelman book) seemed to work best. The zinc version came out red to purple, which can be pushed around in the final wash by adding a bit of acid or base, respectively. The alum version came out mostly yellow. I mixed together equal parts of the alum and zinc rosinates, then cold-mixed them with solvent and oil to get my base colorant, which is still on the deep red side. Since alizarin is a litmus test, you have to be carful what you mix it with or put it on. It can change color. Below is a test over a couple of different grounds. It turned purple on the bare wood (toward the bottom).

David, I couldn't find specific chemistry of leaves, but trees don't do much other than take in CO2 and H2O and some trace minerals to make tree stuff, hydrocarbons of some sort. Burning is the most effective way of converting it back to CO2. I don't know how much is converted to CO2 in composting, but I'd bet there are more hydrocarbons left over than in burning.