strong vs weak wood

[thetyreman]

I had an instance today with some spruce that on the surface looked fine, however when I started working the piece it was a lot weaker than any other piece of wood I've ever encountered, and unusually soft and brittle.

why is it that some pieces of the same species vary so much in strength?

 

[adidat]

sounds like it was rotten?? when you say soft do you mean spongey?

occasionally i come across a patch of rot that has since been dried out in the kiln and turn to hard sponge.

Adidat

 

[thetyreman]

it didn't look rotten to me, it was definitely weak though,it split a lot easier than it normally would using a chisel, and the grain tore out and split when trying to cut a mortise hole, not for anything serious, was just surprised, it felt different to normal like there was stress in the wood somehow, not easy to describe.

 

[MusicMan]

It sounds as if it could be reaction wood. This is wood that is in compression (in softwoods), occurs on the bottoms of branches and on the lower side of tilting trunks. It is what holds the branch (or tilting trunk) up and indeed is under stress. It also has different (larger) longitudinal shrinkage than the 'good' wood, and can go "furry" when planed. It's got very different properties than good wood. In bad cases, such as a strongly leaning-over trunk, it can go almost half way through the wood.

You can recognise it in cross-section as very asymmetrical growth rings. And in sawing, because release of the stress on sawing can cause the kerf to close up. It's the main reason we use riving knives.

There is a good article here: https://en.wikipedia.org/wiki/Reaction_wood

Keith

 

[novocaine]

damn you trees and your natural desire to survive, why can't you be like plastic and be uniform all the way through, damn you I say, DAMN YOUUUUUUUUUUUU.

happy days.

 

[MusicMan]

damn you trees and your natural desire to survive, why can't you be like plastic and be uniform all the way through, damn you I say, DAMN YOUUUUUUUUUUUU.

happy days.

Nah, that would take all the fun outa woodwork!