EIR TOP?

[Dave Bagwill]

Setting aside for the moment the issue of my sanity: if 'someone' were to build an instrument with a hardwood top - say, EIR, what would be the thinking about top thickness? I'll do some research on it, but just wondering if anyone has ideas and/or experience with hardwood top thickness.

[John Parchem]

In Brazil one use to be able to find guitars with beautiful BRW tops. They all sounded like bricks. I do not know if that id the BRW top or they were just badly made.

I have no idea of how thick to make it. I wonder if you wanted it for looks, get a very thin veneer and put it on spruce.

[TonyinNYC]

Dave,

Hardwood tops can work as we can see by the popularity of all koa, all mahogany and other hardwoods. I had the good fortune to speak with a full time builder, Steven Kinnaird, when I was making my all Koa guitars. For the most part, hardwoods are not as stiff along the grain as spruce. They are stiffer across the grain however. My koa tops were .110 for the OM and .115 for the dread. Probably a bit thin by some people's standards for a hardwood top, and thick by other's standards. That thickness worked well for me. For EIR...well you got me! It is more dense than koa, so it will probably need to be thinner to get to the same mass as my tops. I pretty much braced like I would have for a spruce guitar but scalloped a bit more.
Here are pics of the soundboard bracing on both the OM and dread tops:
OM

Dread


The brace behind the bridge plate on the OM was added at the suggestion of Steven Kinnaird because I was worried I had made the top too thin. I had not. But there was no way to know until I had strings on it. They both sound great.
Any questions? LOL

Tony

[Dave Bagwill]

There are a number of all hardwood instruments out there, so the concept is 'sound' - ha ha - thanks for the input.

What I'm doing is, building a prototype for the 3 instruments I'll be building for Love146 - this was on the other forum, where all the materials EXCEPT the dang-gummed black fiber binding - were donated by members of the forum and a few of the sponsors.

I'll probably have to finally break down and build a deflection tester and/or a body resonance tester to see what the eir top is doing as I thin it.

[TonyinNYC]

Any reason you are using EIR for the tops of these donation instruments and not spruce or cedar?

[Dave Bagwill]

My bad - on the three love146 instruments I will be using the materials donated by the forum - spruces. This prototype is mainly just to build one to the plans I've drawn up to iron out any bugs.

[TonyinNYC]

Ahhhh. Just checking. It is also a good opportunity to test an EIR topped instrument. It might be just what the world has been looking for!!