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Experiment in Sonics

Four boxes, all the linings, tops, backs and sides are consecutive slices, of spruce and padauk, all built to the same specs.

Any predictions on the sonics if

One back and ribs were left unfinished on the inside.
one back and ribs were coated inside with epoxy.
one back and ribs were coated with polyester resin
and the final one with a Polyester and Satin Weave Cloth Laminate

Any idea of the effects of coating inside backs and ribs.

Me wood be interested in hearing your input before me close up these boxes.


thnkx
Padma

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Probably not answering your question, but the polyesters I've used have a LOT more damping than the epoxies I've used. So I only use epoxies now.

If you're just looking for a bit of moisture resistance, shellac's not bad, and a lot more user friendly, but it won't waterproof it.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I would say that if you're building to dimension specs, then any correlation between the outcomes will be hard to attribute to just the one factor of finish on the insides. Consecutive cuts will still very probably have different material properties of stiffness and density. As would your back and sides. As would your brace stock. And since you don't like to crack out the Maths and measure and record the data, how will you know which factor caused a particular sound change?
Now, if you were to build a larger sample size, say 10 of each or even four of each, you may get a better idea of the general trend of influence....

aint gonna happen

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Audiences and dispensations on Thursdays ~ by appointment only.


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unfinished will be louder/livelier. just my guess.

I that case, I predict you will definitely like one the best.

If you can't make a matched pair that actually sound the same you're not going to learn as much as you'd hope from these types of experiments, unless you can make LOTS of samples. Too many variables....

Of course they will all sound different! Will the difference be large enough for humans with normal auiditory senses to percieve? Maybe, but it might be pretty difficult to attribute any differences to finish on the interior of the guitar, especially with a sample size of 1.

On the other hand, this kind of test could be effective in determining what DOESN'T work! If one sounds bad, there's your first clue. Of course you'll have to build one or two more that sound bad to be sure that's what's causing it....

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Thanks guys....
let me reword the question...

What effects would lining the inside back with fiberglass have on an instrument?


thanks

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Audiences and dispensations on Thursdays ~ by appointment only.


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Gee thanks Flip,

Duh Padma knows a few trolls and ogurs, one dragon and a couple of wizards, have rescued a damsel in distress and spun a few princesses on the ball room floor in my day. Me even saw a Queen in a burlesque show once..but ummm, me has never met any fairies...perhaps you could recommend a few?


Sorry Flip...you set yourself up for that one.

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Audiences and dispensations on Thursdays ~ by appointment only.


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Edited in the spirit of good taste.

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Kyle

I use a thin coat of Helmsman Spar Urethane on the inside. Try that in your mix and maybe there will be a lesson for me!!!

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Joe Beaver
Maker of Sawdust

My prediction is that lining the inside back and sides with fiberglass will have a negative effect. Otherwise, wouldn't we all be building Ovation knock-offs?

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

Thank you Todd.

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Audiences and dispensations on Thursdays ~ by appointment only.


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If you saw a Queen in a burlesque show, them fairies were hiding in plain sight!

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."