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PostPosted: Wed Jun 09, 2010 12:05 am 
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Mahogany
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I have the opportunity to check out some really cool old guitars, and I'd like to document everything I can about them. Things I've thought about doing/materials I'll need:

[list=*]
[*]A good camera
[*]Big sheets of paper or poster board to trace the bodies using a half-pencil
[*]Large straightedge and/or framing square to use in taking pictures
[*]Good quality calipers - nut width, string spacing, thicknesses of various parts (headstock, neck, etc.)
[*]Inspection mirror
[*]Light source to stick inside the guitar to check out the bracing pattern through the top[/list]

Other things?


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PostPosted: Wed Jun 09, 2010 12:26 am 
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Brazilian Rosewood
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Neat opportunity! Be careful!
- some old blankets or towels for padding your work table
-(be careful with your measuring tools- a framing square or steel straightedge can do a lot of damage)
- a checklist or a form to make sure you don't forget any of the critical dimensions & data
- pre-cut your posterboard into usable pieces (body, headstock profile)
- a few good quality rules 12" and 18/24" or metric equivalent (you want to get the scale length)

Cheers
John


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PostPosted: Wed Jun 09, 2010 12:29 am 
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If you are really serious about this you might consider a hacklinger thickness gauge.

http://www.stewmac.com/shop/Tools/Measu ... Gauge.html

Expensive, eh?

cheers


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PostPosted: Wed Jun 09, 2010 9:52 am 
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Koa
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Any thoughts on a lighting set up to take an "x-ray" of the bracing.

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PostPosted: Wed Jun 09, 2010 10:04 am 
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Koa
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Regarding the magnets Todd mentioned, you might want to check out this MIMF thread (login req'd) http://www.mimf.com/library/measure_aco ... racing.htm

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PostPosted: Wed Jun 09, 2010 10:14 am 
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Todd,

Great idea for a transfer guage. Not that I'm looking for another project, but that looks like it would work too good not to have one.

Tim


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PostPosted: Wed Jun 09, 2010 3:11 pm 
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Old Growth Brazilian Rosewood
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I think if you are really serious about it an x-ray, hacklinger guage, and a surgical scope you can put a camera on would be excellent tools to have.

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PostPosted: Wed Jun 09, 2010 5:17 pm 
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Mahogany
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Does anyone know how I would go about getting an X-ray of the guitar, and a rough idea of how much it would cost? That's a dream of mine, but I assume it's far too cost prohibitive (and not covered by insurance :))


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PostPosted: Wed Jun 09, 2010 9:36 pm 
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Koa
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I know that someone used their local airport late at night to have a peek at their guitar.

By "x-ray", I meant using a bright light inside the guitar and taking a picture of it in a dark room. What light set up has me strumped though. Everything I have tried is either too dim to work or gets too hot for me to be comfortable leaving it in there.

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PostPosted: Wed Jun 09, 2010 11:15 pm 
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Koa
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I'm a bit apprehensive about dropping a rare earth magnet into a 170ish year old Martin 1, but much less so than sticking a heat source into it. Definitely going to have to practice it first.

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PostPosted: Wed Jun 09, 2010 11:49 pm 
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Mahogany
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Some uber-bright fluorescent bulbs, or some LED light source, should provide enough light without the heat.

I figure the "X-ray" image will help to identify stuff that might not be so evident - repairs, odd braces, etc.


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PostPosted: Thu Jun 10, 2010 12:16 am 
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Brazilian Rosewood
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Lillian F-W wrote:
By "x-ray", I meant using a bright light inside the guitar and taking a picture of it in a dark room. What light set up has me strumped though. Everything I have tried is either too dim to work or gets too hot for me to be comfortable leaving it in there.


Here's and idea that just popped into me head Lil', how about a standard SLR hotshoe camera flash?? You set the flash up inside the guitar and cover the soundhole, set camera on a tripod, the ISO to 'fast', set the focus manually, set the shutter for a long exposure, turn off the lights so you are in complete darkness, open the shutter, trigger the flash, and you got ya xray. [:Y:]

Cheers

Kim


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PostPosted: Thu Jun 10, 2010 1:34 am 
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Walnut
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I have examined quite a few historical instruments and often the problem is not damage to the instrument while measuring but rather making the owner feel like proper care is being taken. I use plastic rules and calipers which are not so accurate but the errors inherent in this sort of examination are greater anyway. As for a light source the trick is to have a dark room, that way you can use a mosdest fluorescent bulb which hardly gets hot to the touch. One handy thing I have made is a small tool which allows me to straddle the braces and lower a "piston" to accurately measure brace height. A plane and some scraps of wood close to the imagined brace separation will allow you to plane the wood until it just fits between the braces.

John Ray
Granada

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PostPosted: Thu Jun 10, 2010 3:03 am 
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Koa
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The Unofficial Martin Guitar Forum has a lengthy thread on photographing brace patterns. there are suggestions for lighting and examples of results. Page 18 of the thread has an x-ray of a 1937 D-18. The resolution is great. If you can x-ray the guitar, do it (and post your results).


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PostPosted: Thu Jun 10, 2010 1:04 pm 
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You could get info on resonant frequencies of the top, back, main air, perhaps weight of the instrument.

Lillian,

For "x-rays" I use two compact fluorescents inside the guitar, and block the soundhole as well as I can. The two light sources minimize shadows. I put the camera on a tripod, turn off the flash, dim the room lights, and hit the button. Sometimes I need to use exposure compensation.

Pat

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PostPosted: Thu Jun 10, 2010 9:44 pm 
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Koa
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Thanks for the info about the magnets Todd. Much appreciated.

Pat, what wattage works best?

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PostPosted: Thu Jun 10, 2010 10:03 pm 
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Brazilian Rosewood
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Pat Foster wrote:
I put the camera on a tripod, turn off the flash, dim the room lights, and hit the button.

If you don't have a digital camera that can accept a 'cable release' (actually an electronic switch these days), it can help to reduce 'shake' and blurred pictures if you use the self-timer. The 10s delay lets the shakes die down a bit before the exposure starts.
IMO, having a decent tripod is the key, as Pat mentioned.

Cheers
John


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PostPosted: Thu Jun 10, 2010 10:23 pm 
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Koa
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What constitutes a "good" tripod?

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PostPosted: Fri Jun 11, 2010 12:15 am 
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Brazilian Rosewood
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Lillian F-W wrote:
What constitutes a "good" tripod?

Lillian-
Heavy-duty enough that it doesn't shake!
A lot of the ones I see (in the 'cheap stores' where I shop ;) ) look like they were made with 3 car radio antennas strapped together- they are pretty wobbly.
One alternative to a standard ('floor-model') tripod is a 'mini-tripod' or 'tabletop tripod' - some of them are quite solid.

BTW, probably not bright enough for the 'X-ray vision' thing, but 'string/tube' LED lights (LEDs in a plastic tube) are handy for working inside guitars.

Cheers
John


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PostPosted: Fri Jun 11, 2010 6:30 am 
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Koa
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Thanks John, I'll start looking around for a decent tripod.

Tried the LED's and that didn't work at all. Which is why I posed the question. I know its been done, seen the pictures, but I couldn't find any real information on the light source other than "use a bright light".

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PostPosted: Sat Jun 12, 2010 7:22 pm 
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Koa
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Kim wrote:
Lillian F-W wrote:
By "x-ray", I meant using a bright light inside the guitar and taking a picture of it in a dark room. What light set up has me strumped though. Everything I have tried is either too dim to work or gets too hot for me to be comfortable leaving it in there.


Here's and idea that just popped into me head Lil', how about a standard SLR hotshoe camera flash?? You set the flash up inside the guitar and cover the soundhole, set camera on a tripod, the ISO to 'fast', set the focus manually, set the shutter for a long exposure, turn off the lights so you are in complete darkness, open the shutter, trigger the flash, and you got ya xray. [:Y:]

Cheers

Kim


I asked my brother and he's gotten rid of his SLR equipment when he got is itty bitty digital.

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PostPosted: Sat Jun 12, 2010 10:04 pm 
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Mahogany
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Just looked into a 1943 Martin 0-18 today. Dropped in a refrigerator light into the upper bout (behind the camera) and used a cell phone camera for the pic - not perfect, but good enough to begin measuring.


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