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Cocobolo Shrinkage
- Thread starter Walt2
- Start date
Nathan the Machinist
KnifeMaker / Machinist / Evil Genius
Moderator
Knifemaker / Craftsman / Service Provider
- Joined
- Feb 13, 2007
- Messages
- 19,003
I have found that just about any natural material can shrink some. I have three suggestions
1: age your natural materials in approximately scale sized pieces a year or two before using them.
2: don't sand to size wood stored in hot moist, or cold dry environments.
3: use resin stabilized materials when on work that just can't tolerate a little movement of the furniture. I've yet to do any work where that was a must have.
A lot of wood that I have purchased for knife scales that started out flat eventually curved a bit after a year or two of storage, indicating to me that it wasn't finished drying. I feel had I used it as it came in, that movement might have resulted in a gap or lifted scale after some time.
And to answer your question. No, I've never noticed significant movement of cocobolo. But then, I've always aged it a year or more before using it.
by the way, treat cocobolo dust as you would poison ivy. Once you become sensitive to it, you can't use it anymore. This can be a good way to get aged stock cheaply. Find someone with a stash they can no longer use...
1: age your natural materials in approximately scale sized pieces a year or two before using them.
2: don't sand to size wood stored in hot moist, or cold dry environments.
3: use resin stabilized materials when on work that just can't tolerate a little movement of the furniture. I've yet to do any work where that was a must have.
A lot of wood that I have purchased for knife scales that started out flat eventually curved a bit after a year or two of storage, indicating to me that it wasn't finished drying. I feel had I used it as it came in, that movement might have resulted in a gap or lifted scale after some time.
And to answer your question. No, I've never noticed significant movement of cocobolo. But then, I've always aged it a year or more before using it.
by the way, treat cocobolo dust as you would poison ivy. Once you become sensitive to it, you can't use it anymore. This can be a good way to get aged stock cheaply. Find someone with a stash they can no longer use...
- Joined
- Oct 3, 2002
- Messages
- 12,297
It all shrinks...
- Joined
- Jun 26, 2005
- Messages
- 1,835
Use sharp belts when grinding and grind at slow speed.
- Joined
- Dec 7, 2008
- Messages
- 7,187
All wood will be affected by changes in temperature and humidity levels.
As an example. I get Koa from Hawaii that is kiln dried to 8%. After it comes out of the kiln and is warehoused the moisture level will eventually go back up to about 12% because of the humidity in the air. If this same piece of wood was sent to somewhere like Arizona the moisture level would eventually go back down to about 8 or 9%.
This happens because wood is porous and will absorb or release moisture to balance with the climate of where it is at. Other than stabilizing the best way to control the change in moisture levels (what causes the wood to move) is a good finish to create a barrier between the wood and the atmosphere. This won't always prevent changes in moisture levels but it will minimize them.
There was also a mention about scales moving. This can happen even with properly dried wood. If one side of a piece of wood becomes even slightly moister than the other the wood will contract on the dry side and expand on the damp side.
Example: if a 1/4" scale that is damp is left laying flat eventually the ends of the scale will curl upwards as the moisture evaporates from the top side faster than the bottom side. If this happens, flip the scale over and let it sit a while. This allows moisture to evaporate from the other side. Continue to flip over the piece in 1/2 day intervals until the movement stops.
Sorry about my rambling and poor grammar.
As an example. I get Koa from Hawaii that is kiln dried to 8%. After it comes out of the kiln and is warehoused the moisture level will eventually go back up to about 12% because of the humidity in the air. If this same piece of wood was sent to somewhere like Arizona the moisture level would eventually go back down to about 8 or 9%.
This happens because wood is porous and will absorb or release moisture to balance with the climate of where it is at. Other than stabilizing the best way to control the change in moisture levels (what causes the wood to move) is a good finish to create a barrier between the wood and the atmosphere. This won't always prevent changes in moisture levels but it will minimize them.
There was also a mention about scales moving. This can happen even with properly dried wood. If one side of a piece of wood becomes even slightly moister than the other the wood will contract on the dry side and expand on the damp side.
Example: if a 1/4" scale that is damp is left laying flat eventually the ends of the scale will curl upwards as the moisture evaporates from the top side faster than the bottom side. If this happens, flip the scale over and let it sit a while. This allows moisture to evaporate from the other side. Continue to flip over the piece in 1/2 day intervals until the movement stops.
Sorry about my rambling and poor grammar.
- Joined
- Dec 20, 2009
- Messages
- 4,423
Does your indoor humidity change from summer to winter? If so, the wood will change from summer to winter.
- Joined
- Dec 20, 2009
- Messages
- 4,423
All wood will be affected by changes in temperature and humidity levels.
Example: if a 1/4" scale that is damp is left laying flat eventually the ends of the scale will curl upwards as the moisture evaporates from the top side faster than the bottom side. If this happens, flip the scale over and let it sit a while. This allows moisture to evaporate from the other side. Continue to flip over the piece in 1/2 day intervals until the movement stops.
Stand them up on edge, so both sides can dry evenly.