Spruce&Maple

[Slim Pickins]

When a custom made mando is being made, how old is the wood that is used before it is used. Is the wood aged or used right away?

[sunburst]

The wood can be used as soon as it is dried to a reasonable moisture content. (6% to 8%)
That can be only a few months, or less if kiln dried.
A lot of builders prefer to use wood that has been "seasoned" for a while (several years).

[Ragamuffin]

I have heard guys say that kiln drying tops distroys them. #I've also heard of people baking their tops in an oven. #Side and back wood is usually considered less critical with respect to air, or kiln drying. #I believe there is a general consensus that naturally air dried lumber is best, but as sunburst points out, it must be dried to a proper moisture content. #With one inch thick, or 4/4 lumber as it is usually refered to, it will take normally two years, or more, depending on where you live and the climatic conditions to reach the proper moisture content. #Also, when you ask how old, I assume you mean from the time it was cut, not how long did it live. #With respect to how long did it live the answer is easy; properly handled, older is better.

Ragman

[sunburst]

With one inch thick, or 4/4 lumber as it is usually refered to, it will take normally two years, or more, depending on where you live and the climatic conditions to reach the proper moisture content.
Four quarter spruce can be air dried in as little as a month in good drying conditions, and within a year in poorer drying conditions. Maple takes a little longer, but 4/4 lumber of almost any kind will be dry within a year if properly handled.

Once again I'll refer to Understanding Wood by Bruce Hoadly. There is a table on page 103 that lists approximate time to air-dry 4/4 lumber to 20% MC (moisture content). That is the aproximate equilibrium moisture content of lumber that is kept outside in the eastern US and other non-desert, non-rainforest locations

Red spruce is 30-120 days
Red maple is 30-120 days
Sugar maple is 50-200 days

Below the table it says:

"Minimum days given refer to lumber dried during good drying weather, generally spring and summer. Lumber stacked too late in the period of good drying weather to reach 20% moisture content, or lumber stacked during the fall and winter, usually will not reach a moisture content of 20% until the next spring, which accounts for the maximum days given."

After the lumber is 20% MC, it's time to move it inside and finish the drying. Drying lumber inside doesn't take long, so the time to get to 8% or so won't be much longer than the time listed in the table.

[Ragamuffin]

Sunburst,

Thanks for the clarification. I live in the mid-west where it can be pretty darn muggy in the summertime. Most of my experience with fresh cut wood has been with red and white oak. I have been trying to find the info. you shared regarding spruce for a while now. Why do you suppose people kiln dry spruce sometimes and risk damaging its cell structure if it will dry so fast naturally? Do you believe that there are other measures that coud be taken to further insure a stable piece of wood.

Regards,

Ragman

[sunburst]

Ragman, Oak, especially white oak, can take longer, 80-250 days, but it seems people confuse drying with seasoning.
It's common to keep wood to "season" for a while after it's dry. Some people believe there is great benefit in using very old wood, but there doesn't seem to be much scientific evidence for any drastic change as wood ages. There might be some changes in the lignin and some of the more volitile chemicals. It certainly doesn't hurt to keep wood longer than it takes to simply dry it, and there might be some benefit in stability.

Spruce is normally kiln dried for economic purposes. Most end users of spruce don't know or care how the wood was dried, they just want a good price. The suppliers make more money by moving the wood fast, so they kiln dry.

If it's properly kiln dried, it should be fine as a tone wood, though I too have heard that air dried is better. I'm not sure.
One thing for sure, spruce is very susceptible to fungus. If sprce is not dried right away, blue mold will move in. If spruce is cut in the muggy summer time, blue mold is almost inevitable without kiln drying.

[Ragamuffin]

John,

Excellent point differentiating between drying and seasoning. Do you have a take on how long it takes a "dry piece" @ say 20% moisture content to come down to 6-8% in an environment of 50% relative humidity?

Also, it sounds like you cut some of your own wood. What is your norm for seasoning wood.

You are a generous contributor here, john.

Many thanks,

Ragman

[sunburst]

Ragman, I have a portable saw mill that I've had and used for almost 20 years. I've also harvested my own red spruce for instrument tops. My norm for drying and seasoning lumber is basically; end seal, stack, leave it 'til I'm ready to use it. In other words, I've usually got so much wood that it takes years to get around to using it, so I don't have to keep a close watch on it's drying.

I dry my spruce in split billets, then saw top blanks out of them. I leave the sawn tops sitting around for a while and then carve them. My red spruce has been sitting around since 1989 and 1990, so, it's dry and seasoned.

As you know, it depends on how thick the wood is how fast it dries at 50% humidity. Guitar tops take just a few days, mandolin tops longer, maybe a week or a little more. It's best to check the moisture content with a moisture meeter or some other way. The easiest way to know when small pieces like top blanks are done is to weigh them every couple of days and record the weight. When they quit loosing weight, they are dry. That's more reliable than using time as a guide.

[Ragamuffin]

John,

That's good advice. I have a very accurate scale I'll include in my arsenal.

Thanks again,

Ragman

[Spruce]

"#Why do you suppose people kiln dry spruce sometimes and risk damaging its cell structure if it will dry so fast naturally?"

Simple answer...
To prevent fungusing in the sapwood....

In all species of spruce except Sitka, the sapwood is used in the final billet and instrument if it is healty, but is soaked (and I mean soaked) with water, regardless of when the tree was felled...

It must be KD'ed in most climates if you want this sapwood to remain un-bluestained, especially if you leave it larger single-instrument hand-split billets...

This applies to maple (if not moreso) as well....

"Spruce is normally kiln dried for economic purposes. Most end users of spruce don't know or care how the wood was dried, they just want a good price. The suppliers make more money by moving the wood fast, so they kiln dry."

Nope....
See above....
(Or at least this is my take on it)...

It's much more expensive to KD wood as opposed to AD'ing it, with fuel costs, extra handling, etc. etc.

If you could just stack the wood to AD for "30-120 days" without fear of fungusing, that would be the economical way to go...

Fungus, or rather the prevention of it, is the issue in the transcontinental spruces and maples, and is the primary reason for some form of artificial drying...

Or at least it is around here...

[Ragamuffin]

Spruce,

So is there a prefered way to kiln dry tone wood to deal with the fungus issue and not distroy the tone values? Is this what skilled luthiers are checking for when they scope out a piece of spruce? I've heard mention of case hardning from some aspect of kiln drying ie. too hot too fast, or some such thing. For a novice like myself, how do I really know if I've got a potentially good piece of wood? The first mando I built from a Stew Mac wound up sounding extreemely bright and tinny, even though I graduated to prescribed dimensions. In reflecting, I wonder what, if any, part the drying process played in the tonal outcome. I know there were other issues that affected it like too much wood left on the tonebars, but both the top and back seemed pretty stiff by comparison to other stuff I've done since then.

Looking forward to the big box of wood your sending me, Spruce.

Regards,

Steve Ragsdale

[PaulD]

Not that I have personal experience with KD'ing wood (I've air-dried cherry, apricot, and apple woods), but from what I've read the reputation for KD'ed wood having problems stems from people drying the wood too fast. This can cause honeycomb checking or tearing of the grain, which is sometimes not visible from the outside of the board. I've seen furniture lumber with this type of checking and been told this is the reason. I'm sure Bruce can clarify the accuracy of what I'm saying, since he speaks from first-hand experience.

Paul Doubek