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Experiment in Sonics
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Author:  the Padma [ Sun Jun 23, 2013 5:33 pm ]
Post subject:  Experiment in Sonics
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
duh Padma
Author:  Trevor Gore [ Sun Jun 23, 2013 7:08 pm ]
Post subject:  Re: Experiment in Sonics
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.
Author:  meddlingfool [ Sun Jun 23, 2013 11:06 pm ]
Post subject:  Re: Experiment in Sonics
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....
Author:  the Padma [ Sun Jun 23, 2013 11:10 pm ]
Post subject:  Re: Experiment in Sonics
aint gonna happen
Author:  nyazzip [ Sun Jun 23, 2013 11:11 pm ]
Post subject:  Re: Experiment in Sonics
unfinished will be louder/livelier. just my guess.
Author:  meddlingfool [ Mon Jun 24, 2013 12:16 am ]
Post subject:  Re: Experiment in Sonics
I that case, I predict you will definitely like one the best.
Author:  Alan Carruth [ Mon Jun 24, 2013 12:50 pm ]
Post subject:  Re: Experiment in Sonics
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....
Author:  Rodger Knox [ Mon Jun 24, 2013 1:10 pm ]
Post subject:  Re: Experiment in Sonics
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.... beehive
Author:  the Padma [ Mon Jun 24, 2013 1:27 pm ]
Post subject:  Re: Experiment in Sonics
Thanks guys....
let me reword the question...

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


thanks
Author:  the Padma [ Mon Jun 24, 2013 2:03 pm ]
Post subject:  Re: Experiment in Sonics
Filippo Morelli wrote:
... but best just to get a pin and a few faires and see what happens.

Filippo


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? laughing6-hehe


Sorry Flip...you set yourself up for that one.
Author:  SKBarbour [ Mon Jun 24, 2013 2:08 pm ]
Post subject:  Re: Experiment in Sonics
Edited in the spirit of good taste.
Author:  Joe Beaver [ Mon Jun 24, 2013 4:44 pm ]
Post subject:  Re: Experiment in Sonics
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!!!
Author:  Pat Hawley [ Sat Jun 29, 2013 6:54 am ]
Post subject:  Re: Experiment in Sonics
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
Author:  the Padma [ Sat Jun 29, 2013 12:00 pm ]
Post subject:  Re: Experiment in Sonics
Thank you Todd.
Author:  Spyder [ Sun Jun 30, 2013 4:15 pm ]
Post subject:  Re: Experiment in Sonics
If you saw a Queen in a burlesque show, them fairies were hiding in plain sight! :shock:
laughing6-hehe
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