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| Baking Tops http://luthiersforum.com/forum/viewtopic.php?f=10101&t=42821 |
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| Author: | JustinNorth [ Mon Feb 24, 2014 2:11 pm ] |
| Post subject: | Baking Tops |
If there is already a thread about this, I apologize. I did a search for the word "bake" in the Building Forum, and the only thing I saw was information on various ways to prepare goats for consumption. Dana Bourgeois is offering traditional models that include tops that have been baked at a low temperature over a certain amount of time, the idea being that it "ages" the wood ahead of building to give the guitars a more vintage or aged tone. The baking is supposed to "cook out" things that would normally work their way out of the wood on their own over the course of many years. I own a 30 year old Martin D-18 Vintage Series, and it's the best sounding D-18 I've ever played, and I've played new Vintage Series D-18's. I have a friend who just inherited his great uncle's 1952 Gibson J-50 and had it repaired, and I got to play it over the weekend. It is hands down the best sounding Gibson dred I've ever played. Have any of you tried aging your tops using heat? Did it work? Do you think that this is a marketing scheme? It seems like everyone agrees that all other things being equal, older guitars sound better, and anything that can be done to make a better sounding guitar should at least be considered. |
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| Author: | jfmckenna [ Mon Feb 24, 2014 2:53 pm ] |
| Post subject: | Re: Baking Tops |
I've never done it but from what I understand the purpose is for crystallizing some resins and driving out the bound up water in the cells. You get it really dry and the cells actually shrink and won't get back to that full size again. Then let it sit in your shop till it gets to your targeted RH. That being the case the wood is going to absorb less water in the future so it moves less with changes in humidify. That means it's less likely to crack. It's thought that this is what happens when wood ages, it becomes more stable. That's my understanding and I'm sure I will be corrected or added too. Saying that it makes for a better tone imho sounds like marketing. Saying that it makes a more stable top... ummmm, okay I'll buy that. |
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| Author: | Colin North [ Mon Feb 24, 2014 4:34 pm ] |
| Post subject: | Re: Baking Tops |
Here is one of the threads concerning this http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=22709&hilit=oven+for+drying There are several others. |
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| Author: | Joe Beaver [ Mon Feb 24, 2014 5:36 pm ] |
| Post subject: | Re: Baking Tops |
I bake all my tops. It does help by solidifying the pitch and I believe (no proof) that it allows the tone to reach that aged guitar sound much sooner. |
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| Author: | JustinNorth [ Mon Feb 24, 2014 6:42 pm ] |
| Post subject: | Re: Baking Tops |
Joe, do you have a special "oven" you use for this? Sent from my iPhone using Tapatalk |
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| Author: | nickton [ Mon Feb 24, 2014 6:46 pm ] |
| Post subject: | Re: Baking Tops |
this was a big topic a few years back. I'm surprised you can't find a thread on it. I've tried it too. Seemed like a good idea at the time. sorry for the vagueness. I'm just getting back into this again. |
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| Author: | TonyKarol [ Mon Feb 24, 2014 6:50 pm ] |
| Post subject: | Re: Baking Tops |
200 degrees F for 2 hours .. leave the tops in the oven to cool naturally, don't take them out after the timer goes .. everything I can fit in gets cooked, except sinker redwood .. I had one real beauty crack .. everything else is fine. Which oven .. the one in the kitchen wall !!! |
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| Author: | Casey Cochran [ Mon Feb 24, 2014 7:41 pm ] |
| Post subject: | Re: Baking Tops |
Just don't forget to take it out before the Mrs. preheats the oven for cornbread!! |
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| Author: | mkellyvrod [ Mon Feb 24, 2014 9:05 pm ] |
| Post subject: | Re: Baking Tops |
This is interesting topic. May be a dumb question, but can you bake with the rosette already installed? Only reason I ask is that I already have two tops with rosettes installed, otherwise I would bake first. Thanks. |
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| Author: | meddlingfool [ Mon Feb 24, 2014 10:23 pm ] |
| Post subject: | Re: Baking Tops |
No way! You glue seam will separate. Folks are baking their tops in separate halves, usually in raw un thicknessed form. Some folks find the need to make like an old tennis racket frame to stop the ends from warping, or at least sticker and weight it in the oven. That's why I gave up on it. I also noticed that even coming from a 40% RH state, they would weigh approximately 15% less than when going in, but also lose around 15% of stiffness, but regain the weight after sitting back in 40% RH, without regaining stiffness. Mind you, the sample group I tested was not large enough (forget how many) to give me an unshakeable opinion on the subject. I just got a ten pack of sitka, maybe I should re look at it.... |
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| Author: | Trevor Gore [ Tue Feb 25, 2014 1:46 am ] |
| Post subject: | Re: Baking Tops |
Here's another link to bakery. |
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| Author: | mkellyvrod [ Tue Feb 25, 2014 6:51 am ] |
| Post subject: | Re: Baking Tops |
Well meddlingfool, mine was a dumb question  - thanks for the response. Now Trevor has given me even more to ponder. Sounds like a good idea to drive the moisture out of the cells, but some of the data that was presented indicated that there was not that much improvement. Think I will bake one half of a set (mark a line 6 inches in from edge as suggested) and see how much lasting shrinkage there is. My wife's away for the week, shouldn't be a problem. Which tastes better spruce or cedar?
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| Author: | B. Howard [ Tue Feb 25, 2014 8:17 am ] |
| Post subject: | Re: Baking Tops |
The process Bourgeois is using involves more than baking, it is called Torrefaction. It involves a kiln type machine called a reactor. The wood is held at low temps (around 200degrees F) in an oxygen free environment for a specified time based on wood species and amount of conversion wanted. Not something you can duplicate at home or in your shop. It causes changes in the cellular structures of the wood similar to but more or less reverse of the plasticization that occurs when wood is steamed. |
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| Author: | JustinNorth [ Tue Feb 25, 2014 10:08 am ] |
| Post subject: | Re: Baking Tops |
You're right, Brian. I forgot that it's done in an oxygen free environment. I find it really interesting that someone like Dana Bourgeois is using this process. I think it aligns perfectly with the type of instruments he's trying to build, but I guess I'm just used to seeing this kind of thing used by factory companies as marketing to sell a guitar with an up charge. Obviously I'm not saying I've ever seen a factory guitar with a top that has been through torrefaction. But this does seem like something that one of those companies might do. They're usually the ones with enough cash on hand to tell their R&D dept to build a few guitars and try it out. |
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| Author: | Joe Beaver [ Tue Feb 25, 2014 11:09 am ] |
| Post subject: | Re: Baking Tops |
JustinNorth wrote: Joe, do you have a special "oven" you use for this? Sent from my iPhone using Tapatalk Yes, very special. It's my wife's oven. (Don't let her know I use it) One lesson I learned the hard way is to preheat the oven before you put the wood in. I didn't once and the rising heat charred the wood. It was lost. |
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| Author: | JustinNorth [ Tue Feb 25, 2014 11:45 am ] |
| Post subject: | Re: Baking Tops |
Joe Beaver wrote: JustinNorth wrote: Joe, do you have a special "oven" you use for this? Sent from my iPhone using Tapatalk Yes, very special. It's my wife's oven. (Don't let her know I use it) One lesson I learned the hard way is to preheat the oven before you put the wood in. I didn't once and the rising heat charred the wood. It was lost. Do you think it's advisable (read "safe") to try this with Western Red Cedar? I have one top that's joined already and another that I'm trying to find time to join. I could try baking one, but I don't want to waste perfectly good Master Grade cedar if it's going to ruin it. |
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| Author: | Clay S. [ Tue Feb 25, 2014 12:07 pm ] |
| Post subject: | Re: Baking Tops |
I don't think cedar moves as much as spruce with humidity fluctuations, but is more delicate in other ways. I don't think baking it would give as much benefit and be more risky. |
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| Author: | grumpy [ Wed Feb 26, 2014 10:51 am ] |
| Post subject: | Re: Baking Tops |
The ideal temp is 212f (a bit lower if you're at higher elevations), because it's at that point that 100% of the moisture will be driven from the wood. But 200 will get awful close..  Also, you must leave the oven door slightly open to allow the moisture to escape the oven. Most ovens won't maintain temps as low as these anyhow, so leaving the door slightly open will help. Get a good accurate thermometer(a remote kitchen therm. with a separate probe is ideal), and do a "test run" with junk wood first, as some ovens are truly awful at maintaining temps and it's easy enough to scorch your wood is your oven is one of those.... We can also make a temporary baking chamber by making a plywood box and using a lightbulb or two and a dimmer switch as the heat source. Make an opening at the top of the box to allow moisture to escape. Make a baffle so that the light doesn't discolor your wood. |
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| Author: | wbergman [ Wed Feb 26, 2014 4:37 pm ] |
| Post subject: | Re: Baking Tops |
Do not do this if there is any wax anywhere on the wood. Above the melting point, wax will flow just like water into the wood and never come out. You may not notice the penetrated wax, but it always has the potential to compromise glue joints and finishes way out into the future. |
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| Author: | grumpy [ Wed Feb 26, 2014 7:19 pm ] |
| Post subject: | Re: Baking Tops |
Good point... |
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| Author: | Joe Beaver [ Thu Feb 27, 2014 1:09 am ] |
| Post subject: | Re: Baking Tops |
I agree with McKay, baking cedar is OK but probably less benefit. It doesn't seem to have the sapp like spruce does. I do cook mine anyway. I would not do a master grade anything for my first try. |
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| Author: | Joe Beaver [ Thu Feb 27, 2014 1:09 am ] |
| Post subject: | Re: Baking Tops |
I agree with Clay, baking cedar is OK but probably less benefit. It doesn't seem to have the sapp that spruce does. I do cook mine anyway. I would not do a master grade anything for my first try. |
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| Author: | B. Howard [ Thu Feb 27, 2014 8:47 am ] |
| Post subject: | Re: Baking Tops |
JustinNorth wrote: You're right, Brian. I forgot that it's done in an oxygen free environment. I find it really interesting that someone like Dana Bourgeois is using this process. I think it aligns perfectly with the type of instruments he's trying to build, but I guess I'm just used to seeing this kind of thing used by factory companies as marketing to sell a guitar with an up charge. Obviously I'm not saying I've ever seen a factory guitar with a top that has been through torrefaction. But this does seem like something that one of those companies might do. They're usually the ones with enough cash on hand to tell their R&D dept to build a few guitars and try it out. I heard Dana speak about this last year. Trust me he put a lot of marketing spin on absolutely everything, including the finish. I think I was the only person in the audience who had any hands on experience with materials treated in this way, although not in the art of lutherie. Take the hype and marketing spin what he said makes a lot of sense. I am sure if his promotion of this new type material gains some traction in the market place and sales spike that all the other factories will have their own version soon there after. I have not had the chance to compare two of his guitars side by side, same models, with the different tops to get a idea whether there is any true tonal contribution or if it is mainly fluff. |
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| Author: | James Ringelspaugh [ Thu Feb 27, 2014 6:47 pm ] |
| Post subject: | Re: Baking Tops |
nm |
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| Author: | grumpy [ Thu Feb 27, 2014 10:33 pm ] |
| Post subject: | Re: Baking Tops |
"baking" tops isn't roasting... It's not about changing the tone, or anything like that. It's done simply to bring the wood to zero moisture content, thereby shrinking it(the wood) to its minimal possible dimension, after which experience has shown that it never returns to its previous dimension. In other words, it has been pre-shrunk. Why do it? Experience and tests have also shown that because of this pre-shrinking, it will be much less prone to cracking/splitting if exposed to overly dry conditions, later. That's all there is to it. No magic. No 'pre aged' tone. Just. Less. Chance. Of. it. Splitting. End of story. |
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