Need advice on drying wood

Hello James,

If you buy bowl blanks, cut them round and seal the edges, you can expect it to take one year for each inch of thickness, plus one more year for fairly thick pieces.

If you rough turn to a wall thickness of about ten percent of the diameter; i.e., 1" wall thickness for a 10 inch bowl, they will generally dry in about 3 to 6 months and be ready to final turn. If you weigh them, say once a week or once a month and write down the weight on the side of the bowl, when the weight hasn't changed from the last weight you have reached moisture equilibram and it is time to final turn and finish.

If you are making bowl blanks from a log that you have felled, I recommend cutting the chunks about two inches longer than they are wide to allow for checking in the ends. Cut out the pith and paint the endgrain with a green wood sealer. Again, they will take about one year per inch of thickness to dry. If you have time, rough turn them and they will be ready to final turn in a few months.

I try to separate these pieces with little stickers of at least 1/4" thickness. At one time, I had a supply of old laths that worked very well. Store in a cool, dry, shady location and allow room for air flow around the wood.

There are several other things that will help prevent cracking of rough turned bowls: Turners Choice (CedarShield), Pentacryl, freezing, boiling, and alcohol soaking. You can also microwave dry them if you are in a great hurry to final turn the bowl.

Fred Holder

H> Hi,

If you cut to 10%, you will probably have a lot of restyle available. On a heart up piece with reasonably straight grain you can cut your drying time in half by going a bit thinner. Say your wood is cherry, with a tangential shrink of 7%, you can certainly cut to that and have fudge room. Average dimensional loss is less than a half an inch in a dozen down to 10% moisture, so if you want half inch thick walls, cutting to 3/4 will do it.

Don't leave the bottom too broad, or you'll stress the end grain, possibly splitting it open on the outside. As far as weighing, wait until you see it's shrunk some, then weigh. Wait four-five days and weigh again. Stable with its environment is all you need. If that's 15% where you live, it makes little sense to heat and try to get it lower. It'll only come back.

Check out the _Wood Handbook_ at

for information on how wood dries, and what to expect in the way of shape change. Bulking agents can help stabilize the wood, but they won't "dry" it. That takes dilution into the atmosphere.

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> information on how wood dries, and what to expect in the way of shape > change. >

Although it is a more advanced technique (than drying), some turners actually encourage interior mold by adding shavings, soil and other debris in monitored conditions. Google around for this and dont forget to wear a mask when messing with mold. happy turning, Max!

You've already gotten some very good advice, but I do it differently- mainly because I'm impatient, and don't take kindly to rules. :)

Whether I've purchased a blank or just got a log from somewhere, I don't do much to it until I'm ready to go. Since 99.99999% of my turning stock is free, and not all that hard to come by, I let it just do what it is going to do, and if it cracks or does something else that is particularly nasty, it makes a good campfire in the backyard.

I store my logs with the bark on, and standing on end. If they are in the yard, they generally will spalt like this without too much encouragement, and if they're in the garage, it just keeps the water weight from settling to one side so that the blank is relatively balanced when I turn it. I do not split them and store half logs, and if you ask me, I think that's important. The bark will keep the log from drying too quickly- though the ends will crack. How much the ends crack depends on the wood, but it's generally not more than 2-3" with the stuff I've done this to.

When it's time to turn something, I cut off just what I need with the chainsaw. That being said, I did cut up a lot of square blanks about a year ago in the interest of experimentation, and put half of them in the shed out of the sun, and half of them out in the yard unprotected. The ones outside cracked, the ones in the shed are fine- make what you will of that. They were all stickered to allow air to move freely around the entire blank.

Here's where my technique really differs- I don't rough turn, dry, and then finish turn. I almost always turn the piece to finished dimensions in one shot. For this to work, it helps to turn your pieces thin- 1/16" - 5/16" thick walls.

When I start to get a piece near it's final shape, I start *sanding* it. What I'm really doing is using worn sandpaper to friction-heat the turning with the lathe at a high speed. You don't want to burn the wood, but hot is good. It can burn your fingers, so be careful. I alternate between this and truing up the blank with a chisel until I'm ready for the final sanding. By the time I get there, the wood is obviously dry everywhere but the bottom, where the tenon is still attached (you can see the color change as the wood dries out).

I then lower the speed to 300-600 rpm, and sand through the grits until I'm happy with it. Yes, this can take a long time- I usually spend as much or more time sanding than I do cutting. When it's ready, I part off the piece, and sand the bottom until *it* is dry.

Then I finish it off the lathe- I used to do the finishing on the machine, but I personally found it to just be too messy.

For what it's worth, I lose very few pieces to cracking using this method- perhaps one in twenty. Even better, it allows me to whip things out in an evening even though I didn't plan six months to a year in advance. About two of every five pieces does warp to a slightly obround shape, but it is usually still pleasing- provided the pith runs parallel to the base, the distortion comes out even.

If I need something to be dimensionally stable, I either make a segemented turning from kiln-dried lumber or simply laminate matching flat lumber to make a blank. The way I see it, dimensional stability is for utilitarian items, and does not need to have wonderful grain or be made from one piece of wood. Those items that are mainly for aestetic enjoyment are perfectly fine with a little distortion, IMO. (and of course, some segmented turnings are amazing.)

All that being said, you might follow what I do exactly, and experience a lot of failures. I generally turn maple, willow, and yellow birch, with a handful of fruit woods in the mix when I can find them, and they all behave themselves. A different climate or species of wood may make all the difference, though!

In addition to Fred's fine advise, a wood dryer built out of a old steel REFER (using a light bulb for a heat source) or a box built out of insulating foam (again using a light blub). Me, if I need to hurry the work, I use a microwave.

Just had a thought... what are the light-blub dryings going to do when they "ban" the old style light blub?

Hi James, Many straight grain timbers left alone will crack with one large radial split from bark to pith along the length of a short log. If such a local timber is plentiful enough to allow for some loss (transition to firewood) the green timber bark and all, can be cut into short logs and left to split naturally and dry or spalt.

When you are ready to turn something or you are told to get rid of that ugly mess, you can often get two reasonably equal turning halves by splitting along the big crack and cutting off a couple of inches at the ends. Not a 100% save with every log, but no method in dealing with green logs is. For that matter, most everything we do in woodturning must deal with probability.

Turn to Safety, Arch Fortiter

But often the splits start out in different places at each end - a considerable yield improvement at fairly low workload can be had by making a single cut from bark to pith along the green log, providing a pre-made "split" for nearly all of the shrinkage to accumulate in.