Knowledge You Can Build On — Est. 1998
reaction wood?
DWFII
>I don't have access to a lot of wood, so much of what I have is limbs roughly 12 inches in diameter with off center piths. I tend to harvest bowl blanks out of the reaction wood.
How much trouble is it to use the reaction wood? I've heard it said that it cracks more readily in the drying. Any precautions I can take? I soak all my rough-outs in alcohol. Will that help?
Anyone with experiences...good or bad...to will share?
DW
In the High Desert of Central Oregon
Re: reaction wood?
Gary Evans, Tallassee, TN
>DW,
According to Dr. Hoadley in "Understanding Wood," the cells of tension wood which are formed in deciduous trees contain more cellulose than normal cells, therefore making them stronger. This should make the reaction wood a little more resistant to cracking.
He also mentions that these abnormal cells often machine differently than normal cells, leaving a wooly surface (sometimes microsopic) that takes stain and finish differently than normal wood.
It has been my experience that the third characteristic of reaction wood is the one that may matter most to turners. Reaction wood cells shrink more longitudinally than normal cells which can lead to excessive amounts of warp.
Here is a picture of a 10" cherry bowl that I suspect contains tension wood. I left the walls about an 1 1/4" thick when I first roughed it out as it was one of the first times I had worked with green cherry and I didn't know what to expect. When I started to re-turn it, I soon discovered that it was going to make a nice plate or shallow bowl. It is pretty round at the moment, with one side 1/4" thick and the other nearly 1".
I wouldn't sweat the reaction wood issue. You may lose a bowl occasionally, but that is what the "educational expense" account is for. 8^]
Gary
Re: reaction wood?
theeviltwinn
>When using logs with the pith off center try to cut your bowl blanks with the grain as balanced as possible across the bowl. By this I mean don't cut your bowls with the grain tight on one side and open on the other. It will crack when drying.
There is more waste this way as you can usually only get one bowl per log instead of two.
Mike
Re: reaction wood?
DWFII
>Mike,
Good tip! I'll keep it in mind,thanks. It may seem obivous to some but even if you know it from reading, you might not have it in your mind when cutting.
DW
In the High Desert of Central Oregon
Re: reaction wood?
DWFII
>Gary,
Good grief!! I hope I don't run across anything like that when turning these pieces I cut. They're big leaf maple and some of the first pieces I got--fresh cut...my choice. :D
thanks for taking the time...
DW
In the High Desert of Central Oregon
Re: reaction wood?
GaryG in MD
>VERY interesting, and very timely. I've got some small "half" branches cut from the fat side of reaction wood. (I cut on the pith and threw the small sides away.) After seeing this, I think I'll leave the walls a little thicker than I would have. Thanks for the pic. ...Gary
