Building for a dry climate

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bigdog1002

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I live in New England where the humidity today is 79%. I am starting a new build for a friend in New Mexico where the humidity today is 27%.

It is going to be a martin style soprano with a one piece mahogany front and back and simple plastic binding. The wood for the body is salvaged from a very old drawer front.

Does anyone have any recommendations on how to accommodate for this climate difference when building ?
 
Build a "hot box"...a closet, an enclosed space under a bench, whatever, and heat it with an incandescent light bulb. Put in a humidity meter and keep it at about 30%. Put the wood you're building with in there for about a week before you start cutting, shaping, and bending and all the time when you're not actually working on it.
 
Rick Turner said:
Build a "hot box"...a closet, an enclosed space under a bench, whatever, and heat it with an incandescent light bulb. Put in a humidity meter and keep it at about 30%. Put the wood you're building with in there for about a week before you start cutting, shaping, and bending and all the time when you're not actually working on it.
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Hello Rick,

I've heard of this sort of procedure before and never understood it. When I was exporting furniture from Central America, we had everything under one (very large) roof, from forest to finished goods.

Wood would come out of our kilns at 6-8% and be up to 14% within twenty minutes. We simply had to learn to engineer our way around all the variables of shipping all over the world to customers in all kinds of environments.

I can't see that something in this equation changes when building musical instruments. Am I missing something?
 
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southcoastukes said:
Hello Rick,

I've heard of this sort of procedure before and never understood it. When I was exporting furniture from Central America, we had everything under one (very large) roof, from forest to finished goods.

Wood would come out of our kilns at 6-8% and be up to 14% within twenty minutes. We simply had to learn to engineer our way around all the variables of shipping all over the world to customers in all kinds of environments.

I can't see that something in this equation changes when building musical instruments. Am I missing something?
Click to expand...

Probably something to do with a 2mm uke top reacting differently to a 1" table top?
 
Beau Hannam Ukuleles said:
Probably something to do with a 2mm uke top reacting differently to a 1" table top?
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Hello Beau,

Are you guessing on this or do you know? It had occurred to me that this might somehow be a possibility, but wood movement doesn't change across the grain based on thickness. An unsupported fixed veneer will split at least as easily as a plank.

The one thing ukuleles have going for them is the narrow width of the top and back pieces. Building with narrow widths have always been one way around splitting problems. Moving away from the one-piece construction should help.

What I still don't see is how "altering your building environment" can be of benefit. Wood absorbs and loses moisture too quickly, and there's no way to control the environment during shipping.
 
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southcoastukes said:
Hello Beau,

Are you guessing on this or do you know? It had occurred to me that this might somehow be a possibility, but wood movement doesn't change across the grain based on thickness. An unsupported fixed veneer will split at least as easily as a plank.
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Hi Dirk,

I presumed (read- guessing) that thick wood dries slower (well it dries at the same rate but takes longer due to thickness) then a thin piece, therefore the 'incubation' period is not as 'delicate' on thick re cracking/checking etc. I want to read "Understanding Wood" to learn all this as I'd like to know the ratio of wood drying re thickness in all directions. I try to sand my wood a bit thinner when i get it to speed up the drying process.

Im actually really interested in Rick's answer as I, (like my humor), live in a dry state and I could use some tips on wood conditioning.
 
Beau Hannam Ukuleles said:
Hi Dirk,

I presumed (read- guessing) that thick wood dries slower (well it dries at the same rate but takes longer due to thickness) then a thin piece, therefore the 'incubation' period is not as 'delicate' on thick re cracking/checking etc. I want to read "Understanding Wood" to learn all this as I'd like to know the ratio of wood drying re thickness in all directions. I try to sand my wood a bit thinner when i get it to speed up the drying process.

Im actually really interested in Rick's answer as I, (like my humor), live in a dry state and I could use some tips on wood conditioning.
Click to expand...

Hello again Beau,

You are absolutely correct about the length of time to dry thicker stock. It varies according to species, and there are different kiln schedules that vary by species and thickness. To give a rough example, 16/4 stock (solid bed posts) might take 90 days in the kiln (with 90 days of air dry prior to that) versus 1-2 weeks for 4/4. Veneers, on the other hand, would go through a drying oven that looked a little like a giant Quiznos sandwich heater. 10 minutes or so to dry those.

I've just never been convinced that standard ukulele or guitar construction properly takes all the variables of the modern era (central heat / air, travel, shipment) into account. Controlling a building environment seems to be a good idea if you're selling in that environment, and the instrument will never leave. After all, centuries ago that's pretty much how it was. I don't think luthiers have adapted, but I'll be anxious to hear from Mr. Turner as well.
 
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Hey Dirk,
That got my attention. Are you saying that the industry standard of drying wood to 6-8% MC and assembling instruments at an rH between 40 to 45% at 70 degrees F is not necessary?

Brad
 
Hello Brad,

My guess is that 40-45% is an environment that works well in a lot of situations - but not all. The Carolina furniture factories worked at a little higher humidity, but under the same premise. One of the reasons the furniture industry relocated from the upper midwest was that the Carolina climate (temp most likely) lent itself to more economical control of the building environment.

Just the same, building for "a lot of situations" turns into a nightmare if as much as 5% of your sales are outside the environmental limits of your assembly conditions. That's why, in addition to establishing a relatively friendly environment, pre-finished, floating construction and veneered panels also entered the picture.

In other words, you engineered to overcome the extreme conditions - kind of like bigdog describes. Once you do that, maintaining that controlled environment diminishes in importance.

I'm guessing for factories making solid wood instruments, those parameters are vital, but supposedly also, the warranty problems on solid instruments are the main reason for their higher costs.
 
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Just build the damn thing already! It's wood. It'll be fine.

mun.jpg
 
The 40% - 50% humidity is bogus when you consider most homes are failry well dessicated because of improved glazing, insulation and A/Cs. I run the heating in my shop all year round and have tried de-humidifying it but have rarely kept it at a constant whch of course is also a bogus notion since the conditions in our homes are never constant. Just be sensible - Rick's hot box great is great especially if you are shipping to a climate that is at the other end of your locale's spectrum. Me, I don't ship to dessert countries :)
 
Heat box is not a bad idea, but not a total solution.

Personally would consider sealing the inside of the instrument with some kind of light finish prior to construction using tape to keep finish off of glue area's. More trouble for sure but it will slow the transfer of moisture through the wood and not respond as quick to change. I think you will find that the finish on the interior doesn't effect sound. ( at least to my hearing........ we also own two gas fired kilns and a vacuum kiln along with sawmill and have done a little wood drying in 40 years 4/4 lumber is more like 28-35 days for hardwoods and 8-20 days for softwood in the gas fired kilns. )

Blessings,

Kevin
 
Pete Howlett said:
Me, I don't ship to dessert countries :)
Click to expand...

Pete, so you wouldn't ship to Colorado?

Kevin Waldron said:
Heat box is not a bad idea, but not a total solution.

Personally would consider sealing the inside of the instrument with some kind of light finish prior to construction using tape to keep finish off of glue area's. More trouble for sure but it will slow the transfer of moisture through the wood and not respond as quick to change. I think you will find that the finish on the interior doesn't effect sound. ( at least to my hearing........ Kevin
Click to expand...

I've been meaning to ask- do any builders on here (or that you've heard of) seal/shellac the inside of their instruments. I hadn't considered it until I read that Somogyi seals the entire inside of his instruments to slow the drying process. I tend to listen to people who charge $30,000 an instrument...
 
I send out solid body instruments but make no guarantees for acoustics if they go to extreme environments. As for finishing the interior of instruments... there are so many thoughts on this stuff for GUITARS - need I say more. If you want technical for ukulele you will find everything you need to know from David Hurd. I ignore whar people who charge $30k for and instrument have to say.
 
Ideally you'd keep the humidity of your entire space at about 45% to 50% relative to 70 F. But if that is not possible, then the hot box is an old trick that does work better than keeping wood and building at high humidity levels. I've seen guitar factories in Japan that had entire rooms controlled just for this purpose while their "machining" rooms were not climate controlled. My friend, classical guitar maker Monica Esparza, has a hot closet in her place, and it works for her. I'm just trying to suggest something that may be more affordable than climate controlling an entire shop. And I can almost guarantee that if you build ukes at 70+ % and ship them to 40% and lower places, the instruments will go through some weird changes, and if you don't build with a domed and radiused top and back, you can probably expect cracks.
 
Beau Hannam Ukuleles said:
Pete, so you wouldn't ship to Colorado?



I've been meaning to ask- do any builders on here (or that you've heard of) seal/shellac the inside of their instruments. I hadn't considered it until I read that Somogyi seals the entire inside of his instruments to slow the drying process. I tend to listen to people who charge $30,000 an instrument...
Click to expand...

As for shellac, I think Allen seals his ukes. The shellac won't keep the moisture form entering the wood, but it will even out the absorption and slow the process down. The idea is to protect the instrument from rapid humidity changes. It gives the instrument more time to adjust to the change, thus reducing cracking and other problems. The other advantage to shellac is that it will stiffen the top without adding additional mass.
 
As someone who does some repair work I would stress the benefits of radiusing the top and back. I have seen many cracked instruments caused by extreme humidity changes. Almost all of them have been on flat topped (and backed) instruments. Give the stress a place to go.
 
maclay said:
As for shellac, I think Allen seals his ukes. The shellac won't keep the moisture form entering the wood, but it will even out the absorption and slow the process down. The idea is to protect the instrument from rapid humidity changes. It gives the instrument more time to adjust to the change, thus reducing cracking and other problems. The other advantage to shellac is that it will stiffen the top without adding additional mass.
Click to expand...

Seems that if a piece of wood cracks after shrinking 2% (just to grab a figure) it wouldn't matter if it got there in an hour or a year. It should still crack. Also, can a coat of shellac really stiffen a top? And if it does, why is that desirable? Assuming I've already got it to the stiffness I want.
 
Forget furniture, its apples and oranges here.

If the wood you are using is dry, that is, at 6% moisture content, and it lives in a stable environment of 45-50 humidity at 70 degrees, that piece of wood is not going to gain moisture above the 6% in that environment. I believe this is optimal for building wooden musical instruments. However, if you build in an environment space that is outside under the trees and you can see the ocean or it rains and it feels like a sauna in your shop, then the wood is going to gain moisture like crazy and it won't let go of that moisture. Build in this space and your ukes are going to explode when they dry out, and they eventually will dry out. Besides, how good can wet wood sound even if it stays in a wet environment?

Older, dry 50+ years woods like spruce are highly valued and for a good reason. Instruments made properly will tend to have a longer life span, even if they get moved around in a wet or dry climate. That is why we still have some great older violins and guitars being played. We can't control everything once the uke, violin or guitar leaves the shop, but we can give them the best chance they have by doing it right from the beginning.
 
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