1st build and found curlly sound board

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Bob Howell
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Joined: Sun Jan 08, 2012 4:23 am
Location: Atlanta, GA

1st build and found curlly sound board

Post by Bob Howell »

I got sitka spruce sound board with light figure; beautiful bonus. How do I best finish it. I have installed sh ring and thinned it to .10-13" with top smoothed and perfect. Now I want to seal the top before thin it from the bottom. I will use sealcoat shellac on both sides for that but usually I pop the grain with thin Danish oil first. Is all that going to work on a guitar sound board.

Years ago I read here to plan to bring sb down final thickness by sanding after assembly so you can get out any dings/stains from assembly. I guess that's before bindings so you can see how you are going. Edges, 5/64", center .09-.11".

I know I will likely remove most of what I put on at this stage but it will prevent any areas from being sealed without any oil underneath.

This sb is beautiful but does have uneven grain lines so not top grade.
Rodger Knox
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Joined: Mon Jan 09, 2012 2:02 pm
Location: Baltimore, Maryland

Re: 1st build and found curlly sound board

Post by Rodger Knox »

What are you using for your final finish? Oil under lacquer may be problematic. I don't use lacquer, and have never tried lacquer over oil, so I don't know how it will work.
If your going with an oil varnish final finish, I suspect it would be fine. I would not put shellac over oil, you're likely to lose some of the "pop" that oil on wood gives you. It's a refractive index issue.
I'd wouldn't bother with a seal coat of shellac until after the box is closed, and I would sand that all away before starting the oil. I typically use TruOil, but it's not that different from Danish oil.
A man hears what he wants to hear, and disreguards the rest. Paul Simon
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Barry Daniels
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Joined: Thu Jan 05, 2012 10:58 am
Location: The Woodlands, Texas

Re: 1st build and found curlly sound board

Post by Barry Daniels »

Yep, oil on spruce is not a good idea. Lacquer will pop the grain fine.
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Rodger Knox
Posts: 497
Joined: Mon Jan 09, 2012 2:02 pm
Location: Baltimore, Maryland

Re: 1st build and found curlly sound board

Post by Rodger Knox »

I've used TruOil on spruce, redwood, and yellow cedar soundboards, but I've never used Danish Oil on a guitar, it may be thin enough that penetration into the wood could have some effect on tone. TruOil is a little thicker, and my method of application does minimize penetration of oil into the wood.

I think oil does pop the figure a little better than lacquer, but it takes a pretty spectacular piece of spruce for there to be enough figure to see a difference.
A man hears what he wants to hear, and disreguards the rest. Paul Simon
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