newbie question

Aidan As you have found, wood moves as it dries. During that move it is likely to split. I recommend putting a wax emulsion coating such as Anchorseal on the ends. Better yet, rough turn the object, apply Anchorseal or similar, and let it sit in the shop for 3 to six months to dry. It may help to take a look at preparing rough wood on my web site under

Hi Aidan!

And welcome to the addictive world of woodturning. To answer your question, wood dries at approximately 1 inch per year plus 1. In other words, if you have a two inch square of wood, it'll take about three years to dry. Four square inches, 5 years. Seven inch square, about 8 years. Etc...

As Darrell mentions, you're better off rough turning the piece to about 10% thickness of finished piece, seal it, then let it sit for a few months. I like to alternate that option with some microwave or freeze-drying. If you do a google search, you'll find a wealth of info on the subjects. They both tend to be quicker than the alternative (waiting for months on end), but will also vary in success, depending on the wood.

If you could give us an idea as to the types of wood with which you're working, we might be able to provide more specific info.

Good luck and turn safely! :)

-- Ali T. Borahan AliSails - Fine Wood Artistry & Custom Woodcrafts Web URL:

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Thanks for the replys,

The wood i have been using are ash i think and some rhododendron. (think)

Both were from felled trees and had been lying outside for some time by the look of them. I also have an Oak log about 4ft in length and about 14 inches in cross section.

So if i have it right i should be cutting up the oak to more managable sizes and sealing the endgrain, then stacking it in the garage for them to loose some of the moisture.

I think i should have been collecting wood for the year prior to getting my lathe ;-) any comments most welcome.

Aidan, thanks again

Hey Ali,

Pardon my ignorance but I am also totally new to the art of turning. If you rough turn the piece to approximately it's finished size and then seal it for a few months, how does it dry with the sealer on it? Should I expect problems with the spindles I have to turn? How dry should I have this wood before I start? I would hate to turn about 150 Spindles and then assemble my stair rail and have some of the pieces warp badly and have to somehow remove them.. Any advice from anyone about this would be appreciated.

Thanks,

Blair

Wood dries _in the plank_ at approximately one year per inch of thickness according to those who used to rack it in unheated barns. Planks and turnings in climate-controlled conditions are a completely different matter. I have used 5/4 cherry sawed in the spring and properly stickered for Christmas presents that same year - at ~6% MC after heating for two months.

Common bowls, as most will concede, are almost all endgrain, which, even in non climate-controlled circumstances will lose water at about ten times the rate of face grain. Since, by geometry, the interior of the bowl constricts as the fibers shrink, I can think of no good reason to "seal" it, promoting mildew in the process. Those who have had bowls split from the inside out may now step up and take their shots.

The shrinkage of fibers on the outer part of the bowl, if it proceeds at a rate significantly faster than the contraction of the center, can cause "checking," where the stress is relieved by multiple shallow fissures. It may also grow into a complete thickness split. Woods with prominent medullary rays tend to check and split along those planes of weakness.

Another significant stress on a roughed common bowl is caused by the differential shrinkage of early versus late wood. You can see this in planks flatsawn near the heart of the tree, where the relatively longer portions of earlywood can sometimes exert enough stress to crown or split the wood after the fashion of ( _ pith_) where the underscores compress, elevate, and may even induce a split at the pith area. Woods of diffuse porous habit, or tropical woods with even year-round growth are, of course much less susceptible to this effect, as are woods with interlocked grain or random figure. They become completely unpredictable with burls and such.

The differential shrinkage of early versus late wood is what will affect your spindle turnings, assuming they are along the grain. They will become oval to a degree depending on the difference in moisture content when turned and the present. They may also split radially if parts are near enough to the pith or other areas where the stress of differential shrinkage cannot be relieved by fiber compression. Old timers like the chair bodgers of England used to take advantage of this by placing the ends of rungs where tenons would be turned in hot sand, compressing them by drying, so the dry tenon would be firmly gripped by the drying of the green leg. No glue needed!

If your spindles are not otherwise restrained, they may dry enough to rotate in their sockets. If they do, remember that you don't want to try and glue them all round, but only at one point, so the strains of adapting to subsequent moisture changes - as with seasons - can be relieved in the void, not by breaking the glue joint, or possibly the wood. Either that, or use a flexible gap-filling adhesive like hot glue or silicone.

George, Thanks for your interesting and informative post that isn't just knee kick dogma. I don't know that common bowls are mostly end grain, especially from planks, but that's unimportant in your fine discussion. Arch

Fortiter,

I just had this happen this week with a Red Oak box I had roughed out. Damnest thing. Outside is totally OK, but there's one split on the inside surface of the lid piece.

_____ American Association of Woodturners Cascade Woodturners Assoc., Portland, Oregon Northwest Woodturners, Tigard, Oregon _____

C'mon, it was end grain turned, wasn't it?

Yeah, BUT I've not run into the situation where the inside exhibits a crack that doesn't extend to the outside. In this case it's inside only. Additionally, the lower section of the box doesn't show any cracking in the same place (the crack runs to the bottom face of the lid).

Here're a couple pics if anyone's curious:

_____ American Association of Woodturners Cascade Woodturners Assoc., Portland, Oregon Northwest Woodturners, Tigard, Oregon _____