Nylon string top...

[Nick Dingle]

Mate of mine wants me to build him a nylon string. Black back and sides, so I think I'll just use some mahgany I have. Question is, What to pair it with? I have the following....

Sitka
Bearclaw Sitka
Lutz
Italian Spruce
Silver Spruce
Western Red Cedar
Huon Pine
Monterey Cypress
Swiss Spruce

Any suggestions from the non-steel string guys? This will be my first nylon, and I'm gonna buyild it at a steep discount, but don't want to use a top that isn't well-suited to a nylon...

Edit: I'll be building from an Antes plan of a Ramirez for the most part, but finihsing it up more like a Steel String. My mate wants the nylon sound with a steel string style. If that makes any sense....

Thanks for any and all comments.

[Chuck Tweedy]

I'm gonna buyild it at a steep discount, but don't want to use a top that isn't well-suited to a nylon...

Then use any of the spruces or the red cedar that you have gotten cheep. Any of them will work.

[Waddy Thomson]

Lutz makes an awesome nylon string guitar top.

[Alan Carruth]

When I'm sorting out my wood, I put all the stuff with the lowest density into the 'Classical' pile. Usually WRC is lower in density than the spruces, with those going from Engelmann to Euro to Sitka to Red, in order from the lowest to highest density. Those are averages! There's so much variation within any species that the only way to know for sure is to measure. Fortunately, if you're starting with rectangular pieces, it's pretty easy to find the density; you just take some measurements to get the volume and find the weight. Since I work in metric for this stuff I use kg/meter^3. The usual range is roughly from 300 to 550, and I like to use stuff lower than, say, 400, for Classicals.

It happens that the Young's modulus along the grain for softwoods pretty well tracks the density. Young's modulus (E) is a measure of potential stiffness: any two pieces of wood with the same E value along the grain will have the same stiffness at a given thickness. Since stiffness goes as the cube of thickness, you can take a low density piece of wood with a relatively low E value, and leave it a little thicker to get the stiffness you want, and the top will end up lighter in weight. That's why I save the low density ones for Classicals: there's less energy in the strings, and you need to keep the wight down.

As I say, you can't just go by species with this: I've gotten Red spruce that was below 330 kg/m^3, and Engelmann that was in the 550 range. That particular Red spruce top made a really nice little Classical.

[Nick Dingle]

Thanks guys.

Alan, that's exactly the kind of advice I was looking for. I'm new to the building game, and trying to figure out, rather than thru trial and error at great expense, what to use for what.

My one cedar top is 323kg/m3, and I have a Lutz at 391kg/m3, so I'll offer Col a colour choicefor this go-round.

Thanks again.

Cheers,
Nick

[Alan Carruth]

If the usual relationship between long grain stiiffness and density holds up, I'd make that cedar top around 3mm thick, and the Lutz about 2.5. It would be better to get real numbers, of course.

[Nick Dingle]

Thanks for that advice, too, Alan.

I'm doing a bit of googling to see how to determine the long grain stiffness in the future. So far I've found lots of real science papers, but nothing that looks like it'll help me yet.

Might mostly stick the mass as an indicator, until I get good at the build, or give up(not likely).

Cheers,
Nick

[Rodger Knox]

Just in case you didn't know,
stiffness = modulus of elasticity = Young's modulus
Wood is anisotrophic, and the modulus of elasticity is different along the grain than across the grain.

[Alan Carruth]

Trevor Gore has a nice way of finding the E value along and across the grain using the dimensions of the rectangle, the mass, and frequencies of the lowest 'pure' bending modes in the two directions. You'll need some software that can pick those pitches out, and a mic on your computer, but both are easy to come by. If I had time right now I'd explain it, but you can find Trevor's account pretty easily. There are some pitfalls, of course, but overall it's a pretty good way to go, and simple with modern technology.