Build #2 - Grand auditorium

difalkner · #1 09-12-2023, 09:00 PM

I've talked about this several times and I'm finally back to building #2! When I built my first guitar I didn't have the CNC, actually built the CNC while I was finishing that guitar so the only job I did on the CNC for that guitar was a little bit of the bridge. I began build #2 while I was building #1 but got so busy with high-end custom woodworking for other folks that I set #2 aside; I didn't realize it was going to be for 5+ years.

Now that I have the CNC I would like to use it for a few more tasks in the building of #2 so the first thing I did was to take photos of the body rim and draw that as closely as possible in my CAD program. The short video below is using a Sharpie to draw that outline so I could see how close my digital drawing came to the hand shaped rims - pretty close as it turns out.

The body is Honduras Mahogany, the lining is Maple with a little Curly Maple thrown in for aesthetics, the top will be Sitka Spruce, and the neck will be glued up African/Honduras Mahogany with a Maple stripe (that could change). The body shape is my design but is very close to my Takamine Grand Auditorium (probably close to Martin's GA or OM, as well).

I'll post updates to the build here in this thread so follow along and ask questions, offer comments, and I'll do my best to get this guitar finished soon so I can get started on more guitars.

Steve Kinnaird · #2 09-13-2023, 07:26 AM

Very cool, David. Nice, clean, precise work.
Look forward to more installments!

difalkner · #3 09-13-2023, 01:43 PM

Thanks, Steve!

Rosette inlay test on Honduras Mahogany. This is sort of a twisted vine that I drew and decided to use on the guitar but I wanted to test it first. The Mahogany was already cut and the proper thickness for a guitar top (sort of, it is 0.080" thick). The inlay pieces are Maple and Redheart. There's a short video below showing the steps I used to make the inlay.

Steve Kinnaird · #4 09-18-2023, 11:31 AM

Nice, nice video, David. And the rosette is really handsome.
I don’t think the Bloodwood is too much, except that the contrast between that and the maple is perhaps what you find jarring?
Of course in a spruce top everything will look different; and then perhaps maple will be too subtle!

Steve

colins · #5 09-18-2023, 04:47 PM

Thanks for posting and love that rosette.

And this question is about as technical as I get: Why is it that some kerfing has dozens of tiny cuts in it (presumably to aid bending) while other kerfing like yours looks like a smooth piece of wood? Different woods used perhaps? Or different bending techniques?

warfrat73 · #6 09-19-2023, 07:57 PM

As I understand it "kerfing" is shorthand for "kerfed lining." A kerf refers to the cut made by a saw. So, "kerfing" or "kerfed lining" is, by definition, the stuff with lots of little cuts in it which makes it bendy.

I'd think that this is just "lining" and bent with heat to match the profile.

difalkner · #7 09-20-2023, 08:13 PM

Thanks, Guys!

Yes, I would rather bend the linings and have more of a solid piece than kerfed lining offers. Does it help the sound? No idea, but it has to be stronger. Plus, it's fun to make.

difalkner · #8 09-20-2023, 08:18 PM

Quote:

Originally Posted by Steve Kinnaird

Nice, nice video, David. And the rosette is really handsome.
I don’t think the Bloodwood is too much, except that the contrast between that and the maple is perhaps what you find jarring?
Of course in a spruce top everything will look different; and then perhaps maple will be too subtle!

Steve

I have bounced back and forth between Imbuya Burl, Padauk, Redheart, and Purpleheart for the contrasting wood and am still a bit undecided.

I cut some Curly Maple for the rosette as well as Imbuya Burl and Padauk but I'm not sure if the Padauk is going to bleed all over the Spruce top and the Curly Maple.

The Padauk will certainly tone down once it's exposed to light so it won't 'jump' out at you as much as it ages. But if it's going to bleed all over the top and other pieces of the rosette then I don't want to use it.

Imbuya Burl looks good but the pieces are fairly small and the figure won't really show, plus, it's fairly tame compared to the Redheart and Padauk (or Purpleheart).

Hmmm... undecided still.

H165 · #9 09-20-2023, 08:29 PM

Quote:

or Purpleheart

Purpleheart's dramatic and fun color can fade pretty quickly. Some use sunlight to restore the color, but then you'll be tanning your top...

difalkner · #10 09-21-2023, 08:05 PM

Got started on the top today and decided on Curly Maple and Imbuya Burl for the rosette.

Steve Kinnaird · #11 09-21-2023, 08:26 PM

Looks great!

difalkner · #12 09-22-2023, 03:09 PM

Quote:

Originally Posted by Steve Kinnaird

Looks great!

Thanks, Steve!

Rosette inlay completed but not yet glued or sanded flush -

difalkner · #13 09-23-2023, 03:20 PM

The rosette is completed and the top rough cut to shape (actual shape plus 3/16" all the way around). No finish yet but a little Naphtha on the rosette close-up. Not perfect but I'll take it.

difalkner · #14 10-02-2023, 04:01 PM

Finished the video for the rosette and cutting the top out. Next will be cutting and fitting braces to the underside of the top.

difalkner · #15 10-04-2023, 08:27 PM

I'm in the process of cutting bracing out of split Adirondack Spruce and am considering what material to use for the bridge plate. I know Steve Kinnaird uses Padauk, Bruce Sexauer uses Jatoba (mainly), and most of those amazing old Martins use Maple. So I have Maple, Padauk, Jatoba, Bubinga, EIR, BRW, Bolivian Rosewood, Cocobolo, etc. and all of those seem like they would make good bridge plates.

I'm leaning toward Bubinga for several reasons but none that truly make it seem like a better choice than those that known good builders use on theirs. The Bubinga I have rings beautifully when it's tapped, no idea if that helps as a bridge plate but at least it's fairly resonant as a board.

Thoughts?