Shimmering Mahogany Look

[SGFanboy42]

Hey all, sorry I haven't been more active in the forums lately. College just started for me so I've been saddled with a whole bunch of work lately.

Anyway I've been curious, I have a mahogany top acoustic guitar that has this shimmer in the wood grain especially in the light. Does anyone know how to get that shimmer? Does anyone know what I'm talking about or am I just crazy?

[Bizman62]

Are you talking about chatoyance? Thanks for this forum I know what it means!

So, chatoyance or cat's eye effect is an effect found in gem stones and wood among other things that makes the surface look like it were a mile deep, almost like glowing some inner radiance or reflecting the ambient light from impossible angles. Like being able to see to the very soul of the wood. No, you're not crazy nor do I confess being that (which makes me incurable).

There's a Finnish pop song called "Window to outer space" telling about kids licking a certain dark spot on a rock to make it more shiny so they could then peer into the immeasurable depths of space through that peephole.

The thinner the finish on the surface the stronger the chatoyance effect usually is. Also, it seems to be stronger if the surface has been leveled with a very sharp blade like a plane or a scraper instead of sanding but that depends on how the dust has been removed and how much pressure has been applied when sanding. Applying too much pressure while sanding will bend and burnish the raised grain instead of cutting it flush which agreeably will make the surface level and shiny but close the curtains for the windows to the inner treasure chambers.

[ScottR]

Bizman is correct about what that shimmer - chatoyance is. But you can't just get it, it has to be present in the wood in the first place and not all pieces of wood have it. In fact most do not in any great abundance. It is most often present in the figure of figured woods and often in interlocked grained woods like your quarter sawn mahogany. What you are seeing is light reflecting off glossy wood fibers. the closer they are to parallel to the surface the more reflection you get and when you have fibers that bend or change angles you get that movement, that shifting dancing effect we all like.

If it is present in your piece of wood then you can enhance it by polishing it--smoothing the surface in whatever manner available. The smoother the surface the more visible it is.

SR

[ADFinlayson]

In my limited experience, any wood I've worked with that has some kind of figure other than the grain, e.g flaming, quilting, that normally runs perpendicular to the grain, common with Maple, Walnut, Limba etc - there is usually some shimmer/chatoyance, but as @ScottR says, it's visible in the blank and is enhanced by finishing, not created by finishing.

That figure is far less common in mahogany. I use African mahogany (Khaya) a lot, but I've never been lucky enough to get a piece with any flaming/rippling in it. I've seen a few high end PRS where they used flamed mahogany for the body, but those pieces will be hard to come by and cost a fortune.

[ScottR]

Chatoyance and figure are two different things. Chatoyance is nearly always present in figure--but not always. And it does not require figure to exist. Take some nice ribbon striped (quarter sawn) mahogany or Khaya and polish it up and then hold it to the light and shift it around so the angle to light changes. You'll see the light shimmery areas change to the darker areas and darker areas start to shimmer. I know you've seen that before. That's chatoyance caused by interlocking grain instead of figure. The last couple of guitars I made with zebrawood tops probably had more movement (chatoyance) or any I've come across. When building them I liked to  lay them flat on my little bench and just walk past them and watch the wood dance and shift as I passed by.

SR