New Guy Question: Using Shellac on the Interior

French Polish -- materials -- tools -- methods
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George K
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Joined: Sun Jan 10, 2016 1:36 pm

New Guy Question: Using Shellac on the Interior

Post by George K » Sat Feb 27, 2016 10:56 am

J. Bogdanovich claims shellac is the best finish acoustically, and uses it on the soundboard and the interior of his guitars. Ken responded to the same question about two years ago (fundamental doesn't do much), but maybe hearts and minds have changed over time. I am doing the final sanding and cleanup on a rosewood OM before closing the box and thought I might use a light coat of shellac for ambiance, protection and sealing properties on the sides and back. Do any of the Masters wandering the Halls of Hardwood have thoughts/warnings/dire prophesies they may wish to share?

Thanks for the help.

George K
White River Guitar Repair and Bait

John Link
Posts: 800
Joined: Tue Nov 27, 2012 8:01 pm
Location: Kalamazoo, MI

Re: New Guy Question: Using Shellac on the Interior

Post by John Link » Sat Feb 27, 2016 11:41 am

Ervin Somogyi and others put a very thin 1# cut coat of shellac on the inside. It adds very little weight and impedes the transfer of moisture in and out of the wood as the instrument undergoes changes in humidity. It does not stop this exchange but simply damps it so the wood does not change dimensions so quickly. This may reduce cracking. It may make it easier to remove the dust and grime that eventually accumulates inside. I don't see how it could hurt anything and do it myself these days. Just make sure you avoid coating any wood that will be inside the final glue joint that seals up the box.
John

ken cierp
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Joined: Tue Dec 13, 2011 11:23 pm

Re: New Guy Question: Using Shellac on the Interior

Post by ken cierp » Sat Feb 27, 2016 12:14 pm

Shellac along with about zillion other finishing coatings work fine for guitars ---- double blinds tests have always indicated this to be true. So if you think "X" finish will make a guitar sound better by all means use it. If you want to prove it made your guitar sound better --- well that's a very steep slope indeed.

As for the inside --does nothing one way or the other, but looks cool --- it (lacquer not shellac) was standard on the top of the line Alvarez Yari's.

In other words its not insurance -- with it or not one better treat the instrument very good and protect it from temperature and humidity extremes.

Dave Bagwill
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Re: New Guy Question: Using Shellac on the Interior

Post by Dave Bagwill » Sat Feb 27, 2016 12:19 pm

I have watched a vid of one fella french polishing the interior of his guitar. I'd rather staple a dead skunk to my forehead.
-Under permanent construction

ken cierp
Posts: 3924
Joined: Tue Dec 13, 2011 11:23 pm

Re: New Guy Question: Using Shellac on the Interior

Post by ken cierp » Sat Feb 27, 2016 12:30 pm

There is a price to pay for one ups-manship -- personal or commercial. You really need to do a "value add" analysis before spending time and treasure working outside the time tested construction boundaries.
Dave Bagwill wrote:I have watched a vid of one fella french polishing the interior of his guitar. I'd rather staple a dead skunk to my forehead.

Dave Bagwill
Posts: 5955
Joined: Tue Dec 13, 2011 7:44 pm

Re: New Guy Question: Using Shellac on the Interior

Post by Dave Bagwill » Sat Feb 27, 2016 12:46 pm

The 1lb cut of shellac makes some sense - too thick doesn't look good and attracts a lot of gunk, but a light coat is ok.
-Under permanent construction

John Link
Posts: 800
Joined: Tue Nov 27, 2012 8:01 pm
Location: Kalamazoo, MI

Re: New Guy Question: Using Shellac on the Interior

Post by John Link » Sat Feb 27, 2016 2:19 pm

Dave Bagwill wrote:I have watched a vid of one fella french polishing the interior of his guitar. I'd rather staple a dead skunk to my forehead.
So would I.
John

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