I'm planning for my second build. I used bone for the nut and saddle of my tin uke, but I have another idea for this one.
Following up on a "curb alert" on Craigslist, I picked up some wooden panels decorated with pieces of shell. They make a Japanese-style image, but I really don't care about that. I want to use the shell itself for inlays, etc.
It occurred to me that I could possibly use some pieces of shell on-edge as nuts and saddles. Has anyone tried this? Is it too brittle? Could I maybe laminate several pieces together with epoxy and make it stronger?
I'm speaking to you as a biologist and geologist on this one.
Mother of pearl, or MOP, is the inner shell lining of oysters, some clams, and abalone. It is composed of calcium carbonate, CaCO3, and is both quite soft, being a 3 on Moh's hardness scale (just above talc and gypsum), and quite brittle on edge because it is deposited in very thin layers. You can easily cut it with a not very sharp knife, so imagine what a steel string under tension, being played daily, will do to it. That is the reason it is used for accents, decoration and inlays, because it is very soft and workable, and has a lovely mottled shine, and not for anything load-bearing. I wouldn't try to use it for a nut or saddle, even epoxying several pieces together.
I'm inclined to go with Oily's science on this one but you might be interested to know that 2 people have reviewed the product from stewmac. I don't know the actual composite of their material but it has been done to some extent.
If it is a uke with nylon strings then the tension should be fairly low compared with a steel string guitar. Could be worth a try.