Turning Green Wood

Think LDD!!*G*

Leif

Get Michael O'Donnell's book "Turning Green Wood". It will give you all the answers. It's a great book. To keep green wood from splitting you can't let it dry out until you are done. You must keep it damp and you must turn the walls thin and to a consistent thickness. Thin at top and thick at bottom will guarantee splitting. Spray it with water if have to to keep it moist while turning. Also, if you use fruit woods, they are much more likely to split. This is not to say that the bowl won't warp...it will but that is often the charm of turning green wood.

If you don't want splitting or warping, search out past threads about alcohol, liquid detergent and microwaving rough turned bowls.

Hi Morbius,

There are a couple things you can do to prevent splitting.

1. Turn the walls to a thin consistent thickness.
2. Do what is called twice turned bowls. First you shape the outside of the bowl. Then start the hollowing process, until you have 3/4" - 1" wall thickness. Then remove the bowl from the lathe, and set it aside for a couple months to dry. If you are in a dry climate you will want to place the blank in a paper bag or wrap it in newspaper to slow the drying process. The blank will be warped when dry. Don't worry that's natural.
3. When the black is dry, remount it on the lathe and reshape the outside. Then finish the hollowing of the inside. When done no more splitting or warping.

Good Luck.

Moribus on my web site I discuss turning from green wood to a finished bowl.

Yep.

Read chapter three with special attention. 1) Wood begins to warp once the moisture content is ~30 % by weight. Warp causes checks which can lead to cracks. 2) It's radical difference in moisture content between interior and exterior which we must avoid. Fully expanded fiber close to fully contracted equals stress, which might exceed the strength of the material. 3) Wood eventually reaches equilibrium with the atmosphere, with relative humidity directly correlating to moisture content. Tables in the text should become a part of your wall in the shop. Our task is to control the rate of surface loss to within the range of interior replacement while the wood dries from 30% to around 10%. We do this by controlling the relative humidity around the wood. Buy a hygrometer, because, though there are many ways to control relative humidity, they may be unnecessary. First know what your RH is, then decide if you need to increase it by enclosing your piece.

I like paper tenting, because it's cheap, and paper is, after all, wood, and becomes a new disposable outer layer.

You've also heard a couple of turner legends in the replies so far.

Magic potions, incantations and methods to prevent drying degrade exist only in the minds of turners. Rest of the lumber industry controls the rate of moisture loss and accepts that wood is anisotropic. Could be they're wrong, but if you look at Fig 3-3 and then the construction lumber at Home Depot, you'll see a remarkable coincidence. Your bowls will do the same, so plan for it.

Turnings need to be uniformly thin. Not so. An eight-foot board dries at the same rate as a 5 footer. Since the standard cross-grain bowl turning normally has no point more than a couple of inches from open end grain, this is the proper analogy.

Thanks all.

Leif,does it matter what brand of LDD. I read you & Ron Kents articles on this. TIA Lyndell