what would you do with this wood?

seangil · #1 08-11-2020, 06:33 PM

I acquired some wood, which included some well-aged koa back and sides. The catch is that the koa is pretty thin.

The side pieces are 5" wide and about 0.080" - 0.085" thick. Some pieces have saw kerf marks and some don't.

The plates all fall between 0.10" -0.108". They do not have visible saw kerf marks and look pretty smooth. They are not glued up.

So what would you do with them? Would you try to use them for back, top, or sides? Or are they too thin to try? What is the best use for these?

Thanks,

Sean

Glen H · #2 08-11-2020, 08:03 PM

I’d build a guitar with them. You’ll have little room for sanding or scraping saw marks and need to get the back joint dead flat. But those dimensions are acceptable are finished dims. It just depends on how deep the saw marks are.

frankmcr · #3 08-11-2020, 09:09 PM

Ukulele(s)?

Bass.swimmer · #4 08-11-2020, 09:30 PM

You could arch the back more probably, and add braces to the side if you're worried. That could help

Rangerdave1 · #5 08-12-2020, 06:38 AM

sounds like the back plates will be thick enough. Regarding the sides, I would sand down the sides down to where there is no kerf marks left. You could make laminated sides which will add strength and stability to your build..

And Perhaps if you sand only one side, and a light sanding on the other, you cound use the rough sanded side on the inside of the body.. you would see some kerf marks but you might have enough thickness that way.

Regardless what you do, I think we need to see some photos of this Koa!!

JonWint · #6 08-12-2020, 06:41 AM

I'm gluing up a 00 12-fret koa now with 0.065" sides and 0.095 to 0.105" top and back.

I have a Martin 1900 00-30 with spruce top from 0.075" to 0.090".

redir · #7 08-12-2020, 08:29 AM

I usually thin my backs to about .09"

You will be perfectly fine using that wood for a guitar. Or you can just send it to me

It's nice to have a little wiggle room when joining plates. Just make sure that you have an apparatus set up so that it keeps everything flat and flush when you clamp them up.

ruby50 · #8 08-12-2020, 05:31 PM

I have seen a couple of early Martins with saw marks on the show side of the back and/or sides - you'd be in good company if you couldn't get them all out.

Ed

seangil · #9 08-12-2020, 08:29 PM

Appreciate the advice and people sharing the ranges that they use. It sounds like a number of people have found satisfactory results with wood that is noticeably thinner than these sets. The dimensions that JonWint mentions push farther than I would have expected can work reliably (although it has been pointed out to me that Torres went down to 0.065").

Appreciate RangerDave's idea on living with some internal kerf marks. As you can see, they are not particularly extreme and one set looks like it has already been sanded once (also feels very smooth to the touch). I can definitely live with having some interior kerf in exchange for having good koa. The other wood that came from this collection was dated 1999 and one piece as 1979, so I figure that these pieces have been in storage for a while as well.

I'm in no rush to build them out, however, and will get a few more guitars under my belt with more ordinary pieces before taking chances with these. It sounds like the thickness can work, but that there isn't really room for mistakes.

I'm curious on the laminating idea. I hadn't really thought about that much before, but am getting curious about the idea. I know that it can be done for reasons of structure or sometimes also for a particular tone. Does anybody have experience laminating koa? I am thinking about how it might change the acoustics and therefore influence the objectives/sound that I have in mind for the instrument that I build with koa laminated sides.

redir · #10 08-13-2020, 07:56 AM

That's great looking wood right there and very well aged and seasoned. Nice score!

You definitely do not need to laminate that to use it and I would recommend against it. I don't know of any hand builders that laminate guitar backs but many will laminate guitar sides. I have built a few this way. The idea being that it stiffens the sides and the theory is that stiffer more massive sides can make the vibrating surface area of the top expand more towards the rims and also aides in coupling the top and back.

But the back of a guitar plays an important role in the tone especially if you are going for a live back but even if you are going for a reflective back. So IMHO anyway solid wood for the back is best.

If you were making a guitar for a sailor who lives on a boat or something, then perhaps an all laminate back and sides and even a laminated double top might be a good idea to help protect it from the elements. But again, imho, that's about it.

Neil K Walk · #11 08-13-2020, 12:56 PM

It looks like your question has been answered. The only thing I'd add is to do a deflection test to see how stiff the wood actually is to gauge how it will take being placed under mechanical stress, stabilize your RH and temperature where it will be kept and worked on (it would be a shame to see wood like that split) and proceed carefully.

seangil · #12 08-13-2020, 06:53 PM

Thanks for the further reactions. I am doing my best to keep the wood from extremes, but I unfortunately can't achieve professional shop-like environments.

Redir said that the wood looked aged. I'm curious what clues you look at on wood - or were you reacting to my posting where I said something it about being aged?

redir · #13 08-14-2020, 06:37 AM

Quote:

Originally Posted by seangil

Thanks for the further reactions. I am doing my best to keep the wood from extremes, but I unfortunately can't achieve professional shop-like environments.

Redir said that the wood looked aged. I'm curious what clues you look at on wood - or were you reacting to my posting where I said something it about being aged?

Just commenting on age since you mentioned it was from the 70's and 90's. That is considered well aged at this point. I would not be able to tell just by looking.