Is my walnut too dry ???

[Terry Achey]

I recently purchased about 40 bf of black walnut at a local sawmill to build a aquarium cabinet with doors. Long story short, while milling and cutting boards to dimension, I couldn't help but notice that the wood seemed to be brittle. For example, the edges chipped rather easily when machining. I can't quite articulate exactly why, but the "feel" of the wood while working with it just felt brittle or too dry which has me a bit concerned about picking up moisture later. I'm also concerned that the sawmill operator may have used excessive temperatures to dry more quickly and perhaps damaged the wood cells. Is this even a concern?

My moisture meter only reads as low as 6% to 8% which is what it reads for this lumber.

Welcome any thoughts on the woes of over drying, or otherwise.

Terry

[Michael N Taylor]

Why don't you just let the wood acclimate to your shop for a few weeks and see if that helps, I have seen wood like you are describing and letting the wood acclimate helped it in my opinion.

[David Christopher]

Terry, you might want to try some BLO or simalar. I have some walnut on the lathe now and while I was cutting it was tearing out bad. I wiped on some BLO and let it sit overnight and now it is cutting without any tearout.. its worth a try

[Tony Bilello]

I sounds like dry rot. It really don't matter what the cause is, the important thing is that it is no longer any good and could pose a serious hazard if it collapsed with someone standing near the aquarium.

Daren is a sawmill operator. Maybe he will see this post. He is new on this forum but when he talks about drying and wood condition, he is "The man".

[David Keller NC]

From someone that has built a lot of aquarium cabinets and works walnut frequently....

I would let it acclimate to your shop and see what happens. In general, I think that it's a mistake to build an all-solid-wood aquarium cabinet. The top, sides, and bottom should be veneered plywood, with a solid wood face frame and perhaps a panel door. The reason for this is the very high humidity environment of the interior of the cabinet if it's set up with an overflow and a sump. That's a lot of wood movement to accomodate in the design process, and as the above poster noted, this is an application where failure can have catastrophic consequences (this is also the reason that I don't build these using only glue - metal fasteners are required).

One thing you can do with the walnut to evaluate how it's been dried is to cross-cut the middle of a board, let it stand in your shop's humidity environment for a couple of days, and then carefully look at the end grain. If there are interior checks, it's been case-hardened, and isn't really suitable for furniture (or anything else, for that matter).

[Chip Lindley]

In my experience, *dry rot* is not indicated in this wood. Dry rot is an *oxymoron* in that moisture DOES cause the wood to decay and become unstable, punky, weak, void, and unfit for construction use. The term *dry rot* is mostly used to denote decay in processed lumber, rather than rot in a living or dead tree in the wild. (They said never bury 2x's in concrete for this very reason!)

Terry's walnut appears to have been kiln-dried in a rapid manner, or subjected to too-high heat, which caused the wood to harden and become brittle. (the same thing happens to structural timbers in a hot attic over years)

Dampening the edges with denatured alcohol or even mineral spirits before milling, will help prevent tear-out by giving the wood moisture which will soon evaporate. And, DUHH...what is *BLO*?

[Mike Zipparo]

BLO = boiled linseed oil :)

[Tony Bilello]

In your statement "Terry's walnut appears to have been kiln-dried in a rapid manner, or subjected to too-high heat, which caused the wood to harden and become brittle. (the same thing happens to structural timbers in a hot attic over years)".
What is this condition called?
I have probably always used the term 'dry rot' incorrectly to describe the above condition.

[David Christopher]

In my experience, *dry rot* is not indicated in this wood. Dry rot is an *oxymoron* in that moisture DOES cause the wood to decay and become unstable, punky, weak, void, and unfit for construction use. The term *dry rot* is mostly used to denote decay in processed lumber, rather than rot in a living or dead tree in the wild. (They said never bury 2x's in concrete for this very reason!)

Terry's walnut appears to have been kiln-dried in a rapid manner, or subjected to too-high heat, which caused the wood to harden and become brittle. (the same thing happens to structural timbers in a hot attic over years)

Dampening the edges with denatured alcohol or even mineral spirits before milling, will help prevent tear-out by giving the wood moisture which will soon evaporate. And, DUHH...what is *BLO*?

BLO= boiled linseed oil

[David Duke]

In your statement "Terry's walnut appears to have been kiln-dried in a rapid manner, or subjected to too-high heat, which caused the wood to harden and become brittle. (the same thing happens to structural timbers in a hot attic over years)".
What is this condition called?
I have probably always used the term 'dry rot' incorrectly to describe the above condition.

Tony I've always called the condition described as "case hardened".

[Chip Lindley]

Tony! Not sure what the *Wikipedia* nomenclature for that condition is called. I am no engineer, chemist, or botanist. Just a jack-of-all-trades who's been around for a lot of years. I call it, *attic-baked rafter effect*! The more resins a wood has, the more it will harden severely after years of subjection to high heat. (called plasticization) I've sawed OLD salvaged oak that made sparks fly off my blade! (no metal involved!)

I was remiss to elude to *case-hardening* and *attic-baked rafter effect* being one in the same. Terry's walnut is definately case-hardened. Big difference between too-fast kiln drying and baking for a prolonged period!

Thanks to all for the BLO definition! That one eluded me! I've never used boiled linseed oil for anything. I would think its use in *wetting* stock may have ramifications for staining and finishing later on. Would a faster evaporating agent not be better, such as mineral spirits?

[Tony Bilello]

I think at this point, alot of the internal cellls and cell walls have dried and fractured and nothing can really make them strong again.
Just my opinion, so I still think the wood should be trashed.

[Peter Quinn]

Not sure you are dealing with a serious problem there based on your description. I have worked with some walnut that was just a bit brittle, usually a bit harder and some what heavier than I usually attribute to your average piece of walnut. Not necessarily a moisture issue. Some walnut has naturally brittle edges in square form, some machines like butter. Natural variation.

I have also run into wood that was too dry, didn't glue up well, didn't plane well, didn't machine well. i got a load of old poplar once, KD, had been in a dry warehouse too long, moisture below 6%. I let it sit in my garage all summer and it began to behave again.

As far as case hardened wood, that is a serious defect that poses a grave danger to the user. The out side gets cooked while the inside is still wet, the outside forms a sort of shell that holds the wood seemingly in place as the inside dries, but it is not a stable situation, it explodes with great force when sawed. I have cut into a few case hardened boards and it is not an experience I would care to experience again. If you hit something case hardened you will definitely know it and should take great care processing other boards from that load.

[Cody Colston]

Most all kiln dried wood is somewhat brittle compared to air dried. Also, the term dry rot is oxymoronic as already mentioned. To have rot, the moisture ocntent has to be a minimum of 28-30 percent, which in lumber is not considered dry.

According to Wikipedia,

"Dry rot’ is an eighteenth century term for a brown rot. The term was used because the damage was thought to be caused by internal ‘fermentations’ rather than water."

I'm with the "let it acclimate" crowd here. In fact, that's a good habit to acquire, no matter what wood you are using.

[Terry Achey]

Guys,
Thanks much for all the input. After reading all of your comments I'm guessing that condition of my wood is probably best defined by Chip.

Chip,
your description of "attic-baked rafter" rings a bell with me. Especially southern yellow pine baked to a petrified state in the attic for 40 years or so :eek:.

I've concluded that my walnut isn't "case hardened" as defined by your responses and certainly isn't dry rot. I know what that's like. The wood appears to be structurally stable, just more dry than expected and a bit brittle on edges. The wood was acclimating in the shop for several weeks, however my shop has rather low humidity in the winter with constant heat from my pellet stove.

David,
Appreciate the suggestions on aquarium cabinetry. The back and bottom is 3/4" ply, however the sides, top and front are walnut with raised panel doors. The aquarium is just a small 5 gallon gold fish tank w/aerator. Dado panels with glue and brads as needed. I think it should be solid enough to take the 45 lb. top load.

Peter,
I think you're right that problem doesn't appear to be serious. It glues up fine and I've just finished routing the top edge and other trim pieces this evening without any unusual problems. Just wanted to consult the panel of experts to see what the collective experience has been. They'll be some very unhappy gold fish if this thing collapses :D .

Thanks everyone for sharing your thoughts. Perhaps I'll post the finishes piece on the project forum in several weeks.

Terry