torrefied wood

[avaldes]

I am not aware of a mandolin maker using torrefied wood, but some version of it is now in use by various guitar makers. In addition to the claimed advantages in tone, is torrefied more stable to humidity issues? I am in an area where indoor air is dry in winter. I have a furnace humidifier and use in-case humidifiers, but jut polling experts on here if torrefied is better able to take humidity in the 25-30% RH range.

[Gary Alter]

There are multiple mandolin builders I'm aware of that are currently using torrefied wood, some just the top others the whole body. Some buy the wood already torrefied, others do it themselves. Don Macrostie who builds Red Diamond mandolins has been using the torrefication process for some time and uses an oven he modified himself, there's an article on Don and his mandolins in the current Fretboard Journal. I know Lynn Dudenbostel has built at least one mandolin with a torrefied top and Collings has made a number of mandolins using torrefied tops and at least one where they did the complete body. I don't know if any production Northfields have been released using torrefied wood but I know they have built some prototypes with it. There seems to be a wide range of opinion regarding both the changes in the sonic qualities as well as to how it might play in over time. The process hasn't been around long enough to have a very large sample size. I can't answer any questions regarding how the wood might take a low RH range but I will mention I own a Red Diamond that's been torrefied and it seems to respond to humidity changes the same as all the other non-torrefied instruments that I've ever owned have.

[Eric Hanson]

Gary,
What have you found the tonal qualities to be in your mandolin with the torrefied top; maybe even in comparison with others you have owned or played?

[Gary Alter]

Eric, Last summer I was at a workshop where a fellow student had the same model Red Diamond as I have but his wasn’t torrefied. Both instruments definitely shared similar tonal dna but we both thought my torrefied RD was generally more responsive, a little quicker. It also, to my ear, has more air between the notes, more open and played in. Comparing my RD to other instruments I’ve owned is difficult because we're not just comparing torrefication vs non torrefication, we're also comparing all the multitude of variables that each builder brings to their instruments. Also, since Don MacRostie is one of the only luthiers treating all the wood components it again brings in another set of variables when comparing his instruments to builders who are only doing the tops. In talking with some luthiers who’ve experimented with using torrefication there was also opinions that the process had differring effects with different species of wood so you might like what it does with red spruce but not Englemann. The Music Emporium has high quality video recordings of some of the instruments they have in stock as well as have sold so you can find some sound samples there of torrefied mandolins you can compare. Here’s one of a Red Diamond July 9th Roasted (torrefied). https://m.youtube.com/watch?v=cLZSrKo7RN4

[Eric Hanson]

Gary,
Thank you very much for your feedback. It is very interesting to hear the input from others on this. I like building my knowledge base, and getting a feel for what is out there. I know that it most often depends on the particular piece of wood, and how the builder has used it.
Thaks too for the lead on getting over to the ME website for video listens. I will spend some time on that ad enjoy hearing the differences.

[Denman John]

I know that Austin Clark had a mandolin at Wintergrass this past Feb. that was made using torrified wood. I don't know that exact specifics, but you might want to shoot Austin an e-mail and hear his take on it. I remember it sounded really good! http://www.clarkmandolins.com

[violinvic]

If the rumor got around that the "top" builder were soaking their tops in cow urine, other builders would try it and some pickers would buy it. I am one one who has zero confidence in torrified wood.

[billhay4]

I did try soaking a top in cow urine, but running around trying to catch the urine almost killed me, so I stopped doing that. I now use my own urine. It's not easy, though, as I have to get up five or six times every night for a draw.
Bill

[Mandobar]

Make fun, but there are tonal differences, at least on the Collings models. The all torrified one has a very even voice through all the registers. As they say, the proof is in the pudding.

[Jim Roberts]

Much tonal difference I think. I have a three year old roasted Red Diamond F5 and even the bridge and saddle are torrifeid. It's truly an amazing mandolin. I know a few builders that have tried it and were not impressed, but Don has the process mastered as does Bourgeois Guitar.

YMMV.

[Jim Roberts]

I meant to say a few builders have tried building with torrified wood and we're not impressed. Perhaps the wood is difficult to work with after it's baked?

[sliebers]

I've built a couple guitars with it. It is difficult to work with. It's very brittle and doesn't sand very well. I probably won't use it again until I've got a proven track record with it. I will say it sounded very open, like an aged guitar. I'm not certain it's as stable as claimed. Since there's not much water, or ability to hold water in the cells, it shrinks very fast in low humidity. I got in trouble this winter where a freshly sprayed and buffed body ended up with cracked lacquer while another guitar body that was not torrified sat right next to it with no issues. The torrefied top actually sunk down showing the outline of the tail block. That's with no strings on it, just a body. Got it back to proper humidity and the tail block outline went away. Unfortunately, I now need to respray this one.

[Jim Roberts]

Interesting. Did you roast the wood yourself as Don MacRostie does? I am not a builder but as I understand it there wouldn't be much water in the cells of an old mandolin either would there? Part of of the drying out/aging process?

I live in the dry desert of central Oregon and have had no issues. I frequently take it over the Cascade Mountain range to a very humid climate and then back here to the high desert and so far so good! I met a guy last September at Winfield that played a Bourgeois guitar and it was an phenomenal sounding guitar and it was barely six months old. I wonder if Dana Bourgeois roasts his own tonewood, too?

Interesting discussion!

[sliebers]

The tops were from Stew-Mac. I'm not sure who actually roasts them? It does make sense that the roasted wood should behave like 50 year old aged spruce, but it seems different to me. I've read where Dana had similar problems with lacquer not adhering to the baked wood like it does to regular spruce. He had to change his finish to make it work. Perhaps that's the issue, or it was a fluke thing I encountered. Either way, I'm halting my builds with it until I know more about it. I'm building a test guitar for myself with a top and then I'm going back to regular untreated wood for a while.

[Mandobar]

Dana has his own kiln from what I understand.

[billhay4]

If I'm not mistaken, torrefied wood is heated in a low oxygen environment, not just heated. It is not the same as kiln dried wood at all. This means a special means of reducing the oxygen environment as well as heating to the desired temperature (320 degrees or so). I'd like to know how these builders who supposedly have their own machines do it. Did they buy a kiln designed for this, or make their own.
As for the benefits of torrefication, I'm a skeptic, but not necessarily a non-believer.
Bill

[sliebers]

That's how I understand it too, heated in low, or no oxygen environment. Otherwise, it would catch fire. I too would like to know how small builders do it themselves. I think Don MacRostie made his oven Everyone seems to have their own recipe of how long and what temp. I'm somewhat skeptical too, but believed in it enough to try it. Time will tell how they hold up. Some guys argue that there's not enough water content for hot hide glue to stick properly. I've built one of each with PVA glue and HHG to see what works.

[Gary Alter]

Much tonal difference I think. I have a three year old roasted Red Diamond F5 and even the bridge and saddle are torrifeid. It's truly an amazing mandolin. I know a few builders that have tried it and were not impressed, but Don has the process mastered as does Bourgeois Guitar.

YMMV.

Jim,

One aspect that I haven’t heard anything about, even from the luthiers who are using torrefied woods, is how the tone may change or break in as it ages as opposed to a non torrefied instrument. Since you’ve now had your RD July 9th for 3 years what have you heard from yours compared to other mandolins you’ve had?

[HoGo]

If I'm not mistaken, torrefied wood is heated in a low oxygen environment, not just heated. It is not the same as kiln dried wood at all. This means a special means of reducing the oxygen environment as well as heating to the desired temperature (320 degrees or so). I'd like to know how these builders who supposedly have their own machines do it. Did they buy a kiln designed for this, or make their own.
As for the benefits of torrefication, I'm a skeptic, but not necessarily a non-believer.
Bill

You don't need all that special oven... Factories that do it to hundred guitar tops at time do, or have it done by someone who owns such oven.
Torrefied wood is by no means same as old wood. It may appear similar but the changes in wood are not the same. There are folks (in violin making) who do similar treatment but in wet environment (steam etc. under pressure) and gain similar results.
Torrefied wood has been used for building saunas and outside decking because it won't move as much witch drastic changes of moisture and temperature and it can also change color to nicer dark hues of brown. For instrumnets you don't want to over-do it as the wood loses some of it's strength which is critical. The wood loses some weight as well so if you do just gentle process the strength to weigth ratio won't be worse (the violin guy reports it's better for his wet process) and wood gets nice look of old wood and is slightly more stable.
I did "roast" some wood myself and you can do it at home with no special equipment you just need oven that is large enough for your piece of wood. Process is simple, first heat the wood at 100°C for an hour so you get it to 0%MC. then immediately pack it tightly into thick aluminum foil and seal it with heat proof aluminum tape to keep oxygen away from the wood. Put the wood into oven and roast it (I did 4hours @180°C for rather gentle process) after cooling let it acclimatise back at you shop for few weeks. You will see lots of resin coming from spruce. Different pieces of wood may not darken equally. My test pieces from different trees looked different after roasting.
I'm building two completely identical mandolins (woods from same trees etc), one with roasted top, other without... I don't expect much difference in tone but I guess the roasted will be more stable to humidity changes.

[Mandobar]

Bourgeois purchased the equipment to do this themselves. It is my understanding that some of the other builders are getting their torrified wood from someone in Canada who specializes in this process.

[Jim Roberts]

Jim,

One aspect that I haven’t heard anything about, even from the luthiers who are using torrefied woods, is how the tone may change or break in as it ages as opposed to a non torrefied instrument. Since you’ve now had your RD July 9th for 3 years what have you heard from yours compared to other mandolins you’ve had?

Gary,

I knew my RD was special the day I first took it out of the box and played a few tunes on it but was not sure whether or not it would open up. I have been more than pleasantly surprised as it has matured beautifully and really opened up a lot. It's gotten lots more volume even though the volume was more than ample brand-spankin' new and will do anything you want it to. The AA strings had me mildly concerned the first few months but they are now clear as a bell along with the rest of the notes on the instrument. There truly is not a weak link tonally anywhere up and down the neck on this mandolin.

I had the varnish removed from the back of the neck, replaced the Loar style pick guard with an abbreviated, unbound ebony pick guard and also had Leo Posch install SS frets while it was on his bench and the playability is now enhanced a bit more!