Question about torrefied wood...
Love O Fair
Posted 2021-12-10 10:20 AM (#556579)
Subject: Question about torrefied wood...



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I have recently taken ownership of a torrefied top 1627-4. It’s one of the Glen Campbell run that was the final swan song out of New Hartford in 2018. I have not owned a torrefied top guitar before, though I have read up on them and learned the basic study. This guitar is still in brand new condition, and sounds very nice. But what I am not exactly clear on are the properties pertaining to strength in terms of string tension weight on the bridge and belly wood. Is it stronger? Weaker? More brittle? I ask because I would like to run a set of medium gauge strings on it, but also want to proceed with caution should I happen to like them and want to continue using them for the extended future without having to tune down. Any input on this, or any other torrefied-related info, would be greatly appreciated. Thank you!

Edited by Love O Fair 2021-12-10 10:32 AM
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moody, p.i.
Posted 2021-12-10 12:11 PM (#556580 - in reply to #556579)
Subject: Re: Question about torrefied wood...


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March 2002
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Location: SoCal
I've got 2 torrified top Ovations (retopped by Dan Savage), a 1113 Classical and a 1117 Legend. Let's talk about the Legend. Dan won't put anything heavier that lights or extra lights on his torrified top guitars (he also shaves them a little thinner than Ovation did). I decided to see what mediums would be like on it (A braced). In almost 5 years I have not seen any sign of the top lifting or the bridge coming up. I don't think you'd have any trouble with mediums on your GC......
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DanSavage
Posted 2021-12-11 1:35 PM (#556584 - in reply to #556579)
Subject: RE: Question about torrefied wood...



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Location: Pueblo West, CO

Torrefication causes the wood to undergo the same basic changes that would normally occur as if it had aged naturally.

As wood ages, the resins in it solidify and crystalize. When this happens the wood becomes more resonant.

And, when wood gets old it becomes somewhat more delicate in terms of decreased hardness and increased brittleness. It also becomes darker.

Wood will stop aging after about 300 years due to the fact that all the resins have completely crystalized.

When people started experimenting with torrefication, one of the unexpected side-effects was that, like naturally-aged wood, is that it becomes more opaque.

Some have said this is the holy grail of violin forgery because one of the tests for a forgery is the opacity of the wood. New wood is translucent and until torrefication, there are no artificial process that could alter the opacity of the wood.

Yamaha was one of the first guitar manufacturers to experiment with torrefication. They call their process Acoustic Resonance Enhancement or A.R.E. and patented the process several years ago.

Since then, almost all guitar manufacturers have experimented with torrefied wood tops, to greater and lesser degrees of success.

Here's a link to a YT video that explains Yahama's A.R.E. specifically, and torrefication in general.

See: A.R.E. Technology Explanation Video

One of the cool features of torrefication is that you can target the specific age of the wood you'd like to duplicate be adjusting the amount of torrefication applied to the wood.

This is what Martin does with their Vintage Tone System. (VTS) They wanted to produce guitars that have the same tone as their pre-war guitars. By limiting the amount of torrefication done, they get the effect, but without dramatically darkening the wood as happens when the wood is taken to its limit of aging.

So, their VTS guitars look similar to a non-torrefied wood-top guitar, but have the tone of an older Martin.

All of the torrefied wood I've used to re-top have been 'aged' to their limits and thus are noticeably darker than a new guitar would be. I also believe Ovation used this 'aged' wood for the GC Re-Issue you own.

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DanSavage
Posted 2021-12-11 2:15 PM (#556585 - in reply to #556579)
Subject: Re: Question about torrefied wood...



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Posts: 2315

Location: Pueblo West, CO
I should add that for guitar construction there are one other property we need to be aware of when talking about torrefied-top guitars.

This is peel strength.

Peel strength relates to the structural strength of the wood and how well is resists splitting along the grain. This is very important when talking about keeping the bridge attached to the top. If the bridge is bolted and glued, like some Ovations, then this becomes less of an issue.

The main use for torrefied wood is home siding and decking. Long ago, it was found that older wood resisted absorption of water and when it does get wet, it resists warping. Torrefied wood also has this property.

Just as torrefied wood resists absorbing water, it also resists absorbing glues, such as hide glue or epoxy. This is why I've used the slowest drying glues for the Ovations I've re-topped. If the glue dries/cures too quickly, it won't soak down deep enough and risks having the bridge or braces peel away from the wood, or splitting along the grain taking a portion of the top with it when the torrefied wood fails.

Because I've never tested a torrefied top to destruction, I've always recommended using extra light strings to put the least amount of stress on the guitar top.

Against my recommendations, Paul took a chance and strung his 1117 with medium strings. So far, he's had good luck.

If you decide to string your torrefied top GC with mediums keep in mind that there may or may not be a problem in the future.



Edited by DanSavage 2021-12-11 2:17 PM
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arumako
Posted 2021-12-12 1:05 AM (#556587 - in reply to #556579)
Subject: RE: Question about torrefied wood...



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Location: Yokohama, Japan
Love O Fair - 2021-12-10 12:20 AM

I ask because I would like to run a set of medium gauge strings on it, but also want to proceed with caution should I happen to like them and want to continue using them for the extended future without having to tune down. Any input on this, or any other torrefied-related info, would be greatly appreciated. Thank you!

Hey Al,
First of all congrats on your new acquisition. Hope you don't mind my chiming in! My torrefied Dan Savage 1612 has worn Adamas 1919E medium gauge strings since I took ownership in June of 2017. The guitar has worn no other strings, and has never let me down. I do change strings about once a month; and if I know, I won't be playing the guitar for over a week, I will loosen the strings. I know you would rather not tune down; however, if I'm not going to perform with my 1612 for a longer period of time, I'll just keep it tuned down to D for my practice sessions. No bulging of any kind so far.

One thing I do wonder however is if the factory built Glen Campbell bridges are super-glued to the poly finish? I think that is a common practice among guitar builders today; and Ovation does do that with their Celebrity models. I think Dan glues his bridges pretty much directly onto the sound board which provides stronger adhesion, but makes "peel strength" a very real issue.

Hope you enjoy your torrefied GC!
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d'ovation
Posted 2021-12-12 8:44 AM (#556588 - in reply to #556579)
Subject: Re: Question about torrefied wood...


Joined:
December 2003
Posts: 848

Location: Canada

I thought that torrification results in extra stiffness and tops take a long time to open up. The advice may be to invest in a tone rite device and apply that at maximum setting for at least three months so that wood fibers have better ability to resonate.

 

Also keep in mind that ageing is only associated with growth and improvement to a certain peak age. Then deterioration sets in. If ageing is accelerated then peak may be reached sooner, but natural deterioration will also kick in quickly and overall life be shortened. 



Edited by d'ovation 2021-12-12 8:50 AM
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2wheeldrummer
Posted 2021-12-12 11:23 AM (#556589 - in reply to #556579)
Subject: Re: Question about torrefied wood...



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Location: moline,illinois
LOF you've heard from the expert,Dan Savage,from a layman's persective I've read a couple threads on farcebook about bridges coming off the GC Re-issue so I'd suggest going with a lower tension string like the Thomastik Enleld so you can have a thicker gauge without putting to much ectra stress on the top


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Love O Fair
Posted 2021-12-12 2:45 PM (#556591 - in reply to #556579)
Subject: Re: Question about torrefied wood...



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Thank you everyone, for the virtual plethora of information and advice! I knew going in that Dan would have all the deep details-- ones that others have likely benefited from reading as well.. though I am not exactly certain how a "tone rite" device works for torrefied wood, as mentioned by d'ovation.

From the balance of it all it is looking like a casino proposition on the medium strings-- but from what 2WD said about things read on FB concerning the bridges on this particular GC model I am going to put the brakes that for the time being and look into the Thomastik specs for specific weight numbers in comparison to, say, the EJ16 lights that are on it today. Now, if it were one of Dan's torrefied re-top bridge settings I might have more confidence in trying mediums since Paul and Ken have had clear sailing (even against Dan's own recommendation), but it obviously is not one. The string gauge change is mostly just a matter of curiosity anyway, for experimenting a somewhat deeper tone; though I have to say that I am also really enjoying this guitar strung the way it is-- so for now it is looking like a matter of letting sleeping dogs lay. Thanks again for your input! All considered and appreciated!
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moody, p.i.
Posted 2021-12-12 3:35 PM (#556593 - in reply to #556579)
Subject: Re: Question about torrefied wood...


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Location: SoCal
If it mean anything to you, I've got a 2006 GC reissue. Have always had lights (.12-.53) on it. But's it's to just get a crisper sound.
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Standingovation
Posted 2021-12-12 5:16 PM (#556594 - in reply to #556579)
Subject: Re: Question about torrefied wood...



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Location: Phoenix AZ
Put mediums on it tuned down a full step and capo at the second fret.
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Love O Fair
Posted 2021-12-12 8:16 PM (#556596 - in reply to #556579)
Subject: Re: Question about torrefied wood...



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Location: When??
@Moody - >>>Have always had lights (.12-.53) on it.<<<
Yes, that's what's on this one right now, and yes it is quite crisp. They have always been my typical go-to, and I haven't used mediums on any Ovation in a long time, but from what past I have had with them I would like to see how it translates to this particular guitar.

@Standing - >>>capo at the second fret.<<<
Just not the same humjo as played in full scale length.. which is the sound and feel I am wishing to experiment with on this one. Heck, I might not even like them, but if I do end up liking them, and knowing my own bullheadedness, I will get complacent and/or reckless and/or forgetful and/or lazy in the long range and leave the thing at concert pitch. That's why I was curious about my first experience with a torrefied top as possibly providing some form of stupidity insurance.
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