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Torrefied Wood!
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Author:  DanSavage [ Mon May 23, 2016 9:00 pm ]
Post subject:  Torrefied Wood!

Just one year ago, almost no vendors offered torrefied wood for sale, save John Hall at Blues Creek Guitars.

Now, just one year later, we have the following available.

Stewmac:
Torrefied Sitka spruce soundboards and uncarved Sitka spruce brace stock.

Colonial Tonewoods:
Torrefied Adirondack soundboards and uncarved Adirondack brace stock.

RC Tonewoods:
Torrefied Bearclaw Sitka & Sitka, Carpathian, Englemann & Lutz spruce soundboards.

As a confirmed torrefied fan I would just like to express my appreciation to these vendors for stepping up to the plate and offering these products for sale. I've got several projects lined up for torrefied tops and the choices of soundboards is nothing short of astounding.

Bravo!

Dan

Author:  bluescreek [ Tue May 24, 2016 6:05 am ]
Post subject:  Re: Torrefied Wood!

I have made 7 guitars with Torrified tops this year. I was a fan from the 1st.

Author:  DanSavage [ Tue May 24, 2016 8:37 am ]
Post subject:  Re: Torrefied Wood!

I'm on my third one.

Author:  Ben-Had [ Tue May 24, 2016 2:32 pm ]
Post subject:  Re: Torrefied Wood!

I'm on my 6th torrefied top and I just can't believe the sound, the only issue I had was gluing one with Titebond that didn't hold the bridge. Now I use fish glue and leave clamped over night for all the braces and bridge.

EDIT: I've bought at least one from each of the listed vendors.

Author:  unkabob [ Tue May 24, 2016 9:17 pm ]
Post subject:  Re: Torrefied Wood!

I have yet to see a process for torrefication of spruce. It looks more like snake-oil to me. The only flaw is that some highly regarded builders are recommending or at least building with it.
If it is still around in five years I will accept it as more than just a fad.
Just my opinion.

Bob :ugeek:

Author:  jfmckenna [ Tue May 24, 2016 11:13 pm ]
Post subject:  Re: Torrefied Wood!

What is the issue with Titebond?

I've been keeping my eye on this stuff but like unkabob am waiting for it to have a bit of time testing out there in the wild. I might buy a few sets now and let them age in my shop for a while though :)

Fortunately for me I scored some very old spruce to work with for a while.

Author:  meddlingfool [ Wed May 25, 2016 1:04 am ]
Post subject:  Re: Torrefied Wood!

I've done maybe a dozen or fifteen or something. It is not snake oil. The wood handles, smells,works, and sounds different.

There is a lot of info on the process available with a little digging. There is no small effect, it's not a subtle thing.

For the sceptics, excellent! Always be sceptical, but with an open mind. Why not try it and see for yourself?

Author:  jfmckenna [ Wed May 25, 2016 6:37 am ]
Post subject:  Re: Torrefied Wood!

The reason why I am not trying it yet is because when I hear things like Titebond doesn't work it makes me weary of trying it. My day job is in IT and the general rule of thumb there is when something new comes out let the other guy work out the bugs ;)

I definitely do want to try it... Some day.

Author:  Ben-Had [ Wed May 25, 2016 9:35 am ]
Post subject:  Re: Torrefied Wood!

jfmckenna wrote:
What is the issue with Titebond?

I've been keeping my eye on this stuff but like unkabob am waiting for it to have a bit of time testing out there in the wild. I might buy a few sets now and let them age in my shop for a while though :)

Fortunately for me I scored some very old spruce to work with for a while.

Honestly, I'm not sure but after 2 small failures I'm not trying it again with Titebond. A few years ago I was approached by a fella with a guitar top that supposedly had survived a small fire in the finishing room at the Martin factory back in the 40's. The top had been exposed to the heat and was slightly scorched. Looking back I realize it had similar properties to torrefied wood. I used Titebond on it as well with the same holding issues, bridge popped up and braces came loose in areas. I let him take it for a show he had before he finished paying. He never paid me and never came back so i had no opportunity to fix it.

Author:  DennisK [ Wed May 25, 2016 10:36 am ]
Post subject:  Re: Torrefied Wood!

Has anyone here built with both torrefied spruce and unmodified redwood? If so, how do they compare? When people talk about the properties of torrefied spruce (lower density, more brittle, lower humidity movement, lower damping, and even the darker color) it always just sounds like a process for converting spruce into redwood :P

Author:  jfmckenna [ Wed May 25, 2016 10:56 am ]
Post subject:  Re: Torrefied Wood!

What do they do to 'modify' redwood? I just built a redwood topped dred from wood I got from LMI over a decade ago. I didn't think anything was done to it except to cut the tree down and resaw the wood. It was fine as it was. I have built with curly redwood and that was a nightmare in how brittle it was. That I'll never do again. If torrified is like that then...

Author:  Finn.t.guitar56 [ Wed May 25, 2016 11:08 am ]
Post subject:  Re: Torrefied Wood!

Did you hear about the Spruce plate under the band saw.

It was torrefied!!

Wood jokes :))


Sent from my iPhone using Tapatalk

Author:  unkabob [ Wed May 25, 2016 11:23 am ]
Post subject:  Re: Torrefied Wood!

The titebond issue may be related to the fact that it is a water-based glue. Some of the advertising on the web touts torrefication as a water-repelling process which prevents rotting in door frames. The same hydrophobic properties would tend to repel titebond, kind of like having wax or silicone on the wood surface. Hot hide glue should work but fish glue should give problems "if I am correct".

Just my thoughts.

Bob :ugeek:

Author:  DennisK [ Wed May 25, 2016 11:26 am ]
Post subject:  Re: Torrefied Wood!

jfmckenna wrote:
What do they do to 'modify' redwood? I just built a redwood topped dred from wood I got from LMI over a decade ago. I didn't think anything was done to it except to cut the tree down and resaw the wood. It was fine as it was. I have built with curly redwood and that was a nightmare in how brittle it was. That I'll never do again. If torrified is like that then...

By modified I mean processes like baking or torrefaction. I'm curious about torrefied spruce versus regular redwood, not torrefied spruce versus torrefied redwood. Not that anyone is supplying torrefied redwood as far as I know. I was just trying to word it clearly, which apparently backfired.

Author:  DanSavage [ Wed May 25, 2016 12:27 pm ]
Post subject:  Re: Torrefied Wood!

unkabob wrote:
I have yet to see a process for torrefication of spruce.


If you read Yamaha's patent on A.R.E. they describe how they used the torrefaction process. See: http://www.google.com/patents/US6667429 (US Patent 6,667,429 (Method for manufacturing modified wood))

Here's the gist of the process:

Quote:
Furthermore, since cellulose chains in the wood are partially hydrolyzed and rearranged, residual strain in the wood is resolved and the degree of crystallinity increases. Therefore, a modified wood having a superior dynamic modulus of elasticity (E) and oscillation properties such as damping factor of oscillation (tan δ) can be obtained. The above change is similar to the change in wood which occurs with the passage of time of some hundred years, therefore, it can be said that the modified wood of the present invention is antiquated in the above treatment.

Moreover, since the wood becomes dark brown by the above modification and the contrast of grain is increased, the modified wood can be developed with a transparent and deep appearance while the coating step can be shortened.

...

The high pressure steam contains a large amount of active species such as hydrogen ions, hydroxide ions, hydrogen radicals, and hydroxide radicals, and hydrolyzes cellulose, hemicellulose, and lignin which are main components of wood. When wood is put under the above conditions, the above active species are impregnated into the wood with the steam, and subsequently, hydrolyze hemicellulose, partially repolymerize lignin, decompose amorphous portions of cellulose and rearrage the decomposed portion. Accordingly, residual strain in the wood is resolved, and the degree of crystallinity and the width of micells increases. As a result, the dynamic modulus of elasticity (E) increases and the loss angle (tan δ) decreases. Furthermore, since a part of the decomposed component and extracted component of the wood is removed with water, density (ρ) decreases.

Therefore, in the obtained modified wood, since sound conversion efficiency, which is described by the product of the sound radiation attenuation (external attenuation efficiency) and the inverse of the internal attenuation efficiency of the material, shown below increases, the modified wood can be used as a material for musical instruments having superior oscillation properties.

...

Furthermore, as shown in FIGS. 14 and 15, the density tends to decrease. The maximum change is −8% density in spruce.

According to the high pressure steam treatment, the sound conversion efficiency of the wood is remarkably improved. The above change is similar to the change which occurs in the wood with the passage time of a few hundreds of years; therefore, it may be said that to produce the treated wood of the present invention is to make aged wood. As shown in FIGS. 16 and 17, EL/GLT tends to decrease, therefore, strength of the wood is increased. It is a characteristic after the high pressure steam treatment.

Change in Color

The light brown colored wood turned into a dark brown colored wood with a good appearance and deep color tone due to the high pressure steam treatment. Since the color of wood changes, the coating step is shortened and the contrast in the grains is increased to improve the value of the appearance of the wood.


There was a group who studied wood aged over a long term. The analyzed artifically aged wood using both the dry and wet (steam) processes. See: http://www.citedelamusique.fr/pdf/insti/recherche/bois/obataya-anglais.pdf (Characteristics of aged wood and Japanese traditional coating technology for wood protection)

They found that the wood structure continued to crystalize/decompose and reached an 'obscure' peak at around 300 years, then the process tapered off after that.

Author:  DanSavage [ Wed May 25, 2016 12:44 pm ]
Post subject:  Re: Torrefied Wood!

unkabob wrote:
The titebond issue may be related to the fact that it is a water-based glue. Some of the advertising on the web touts torrefication as a water-repelling process which prevents rotting in door frames. The same hydrophobic properties would tend to repel titebond, kind of like having wax or silicone on the wood surface. Hot hide glue should work but fish glue should give problems "if I am correct".


I haven't noticed that the torrefied spruce that I've worked with is especially hydrophobic. It seems to absorb water pretty easily.

I used Old Brown Glue to joint the tops and glue the braces. I kept them clamped in a gobar deck for 24 hours. Both of the guitars I retopped with torrefied spruce seem to be holding together just fine. The first one was delivered last November and is played every day. I've got the second one and I play it every day or so.

Author:  meddlingfool [ Wed May 25, 2016 1:24 pm ]
Post subject:  Re: Torrefied Wood!

I've had no issues with Titebond and Torrefied. I use HHG on the bridges for all guitars.

Author:  printer2 [ Wed May 25, 2016 8:09 pm ]
Post subject:  Re: Torrefied Wood!

Titebond seems to bead up a little when I used it, I just let it sit a minute before I joined the pieces, not sure if it helped or hurt. The guitar is a year old and have had no problems with it yet. You can really hear the difference in the tap tone between a treated piece and one that was not. Maybe I should do a guitar treated and not, shame my bandsaw it out of commission at the moment, can't do any resawing. I have two top sets that were cut in sequence next to each other, I wouldn't mind trying it with maple. So, untreated top compared to treated with untreated back and sides or one all untreated and one all treated?

Author:  DanSavage [ Thu May 26, 2016 12:28 am ]
Post subject:  Re: Torrefied Wood!

printer2 wrote:
Maybe I should do a guitar treated and not...


That's what I did.

I re-topped a 1976 Ovation Custom Legend a couple of years ago using Bearclaw Sitka spruce and Sitka spruce braces.

Then, this year I re-topped a 1978 Ovation Legend using torrefied Sitka spruce and torrefied Sitka spruce braces.

Both guitars used the same brace pattern. Both had their braces glued using hide glue. The only real difference is that the first one has a walnut bridge and the second one has an ebony bridge.

In short, I built these guitars as closely as possible so that I could isolate any changes in sound to solely the torrefied wood vs. non-torrefied wood.

While they do sound similar, the torrefied top edges the BC top in tone, note separation and sustain. I did a blind sound test with a couple of people and they picked the torrefied guitar as sounding better than the non-torrefied guitar.

Image Image

Author:  jfmckenna [ Thu May 26, 2016 8:21 am ]
Post subject:  Re: Torrefied Wood!

The Ovation is a good platform on which to test but I kind of wish you used the same bridge on both. That's gonna make a difference isn't it? Those look great BTW, nice job! The bear claw looks spectacular.

Author:  DanSavage [ Thu May 26, 2016 9:19 am ]
Post subject:  Re: Torrefied Wood!

Thanks! Yes, I agree on the bearclaw. I'm sorely tempted to try the torrefied bearclaw RC Tonewoods is offering.

I really couldn't say how much a difference the wood used for the bridge makes in final sound of each guitar. As I say, they both sound equally good, with the torrefied top having a slight, but noticeable edge.

Ideally, for this type of comparison I should have used the same bridges. But, I also wanted each guitar to be aesthetically pleasing, which is why I went with the ebony bridge instead of the standard walnut bridge. I'm just not a fan of how the walnut bridges look on these guitars.

I have one more of each type and out of curiosity I weighed them just now. The walnut bridge weighs 17g. The ebony, 32g. I also have a rosewood pinless bridge that I bought from allparts.com. It weighs 27g.

When I drop these on the desk and listen to the tone, the ebony has the lowest pitch sound, the walnut has a medium pitch and the rosewood has the highest pitch.

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