Wood bowing after being carved ?

[IM2HAPPI]

Im having a terrible problem with everything I carve bowing on me. This is happening even on kiln dried wood, old old barn lumber, just doesnt seem to matter what type. The worst was some white oak. The only thing that hasnt bowed is sassafras. Is anyone else having this problem ? Its bowing on the cross grain. Do you think a few days of being clamped down and letting air dry will help after carving ?

[Bill]

The only time I have had this happen is when I do a carving on material 1/2" x 5" x 30" or longer. This happened when doing heavy carving and some moisture. The bottom of the board gets warm and it seems to react like steal and bows down (roller side) to the heated side. I just turn it over put a small shim under it with a weight on top and leave it set and it comes out straight.

[pkunk]

That's really odd! I've never had a problem with any of my carvings bowing or warping. Usually if wood does move when cut or otherwise relieved, it was 'reaction' wood. That is wood that comes from a tree that had stresses when growing.
From Wikipedia
"Reaction wood is formed in response to mechanical stress, and helps to position newly formed parts of the plant in an optimal position. Reaction wood forms when a woody plant part is subjected to mechanical stress. This stress may be the result of wind exposure, excess of snow, soil movement, etc. There are two different types of reaction wood, which represent two different approaches to the same problem by these groups of plants:

* In angiosperms reaction wood is called tension wood. Tension wood forms above the affected part of the plant, pulling it up. It is composed almost entirely of cellulose.
* In conifers it is called compression wood. Compression wood forms below the bent part, pushing it up. Compression wood is rich in lignin.

As a rule, reaction wood is undesirable in any commercial application, primarily as its mechanical properties are different, also it responds differently to changes in moisture."

[Bill]

Paul,
The only time I have had this happen is when I carve the parts for the lamps I make
and there is a lot of material removed completely from the pieces but never on just a carving where the
object on the board has not been cut through and the (Board is intact)

[RBeau1954]

Pkunk is right, wood will move and react. I build furniture and if I am planning down a piece of wood I will always plane both sides the same and let it sit in the shop for a few days or more. If wood is kiln dried then cut only on one side it can happen. Also, the process that they use to kiln dry makes a difference, some places will stress relieve wood which is a longer time period but better. That is where kick back comes from sometimes when you cut a board on a table saw, (Only if you have the splitter removed and we know that no one does that) and as you are cutting, the wood comes back together from relieving the stress and pinches the blade. I would try to find another source of wood.

Rick

[benluz]

How the wood is conditioned after the drying process is important ,by the time the inside of a board is dry typically the outside of the board is over dry setting up a stress or tension condition .To correct this at the end of the drying cycle we add moisture back into the kiln while the wood is still hot to bring the moisture content back up close to where the inside is and relieving the tension.Problems can also arise if wood is stored improperly,if wood is left in an unheated shop ,barn, shed the moisture wills slowly rise until it is at equilibrium with the air around it or EMC.Suppose a piece of this wood is brought in the shop then carved then taken in the house for all to look at .The wood from being in an uncontrolled environment has risen to a 15% EMC depending on what part of the country you are in, now inside especially in winter you are in 8% and lower EMC....now what happens.... the piece begins to dry and unrestrained and depending on growth ring orientation cells begin to shrink some areas more than other creating a warped piece.There are many other factors as pkunk mentioned such as reaction wood ..etc that also contributes to warping.This was just a quick run down on wood movement if you want to learn more go to the www.woodweb.com and read some of Gene Wengert articles.The one exemption on storage locations is barns are lofts in the summer time when the temp gets up to 120 degrees are close to normal use emc,but only in the summer months.
Ben

[pastime106]

I have had this problem in the past when I re-saw and then plane to a thickness of ¼” or less. This would be very much like carving thin areas in a board I am guessing. I have used my compucarve for about 20 hrs now without this issue but have experienced in the past during other projects. My problem seemed to be a difference in moisture content between the shop (Inside the house)and the area in the barn where the wood was stored. What I ended up doing was purchasing a small moisture meter. (Mini Ligno)
Now I will bring a few boards into the shop and let them sit there for a few days. I then test the moisture of the boards and compare that with a current reading of some of the scrap wood that I have in the shop. I generally work with cherry and oak and have plenty of scrap around. When the reading is close to the same (within 2-4%) I am usually in the safe zone. A consideration is also where is the finished project going. If you build it in a basement and place it out in the direct sun, It will eventually warp. As this is my first post I hope it helps.

[benluz]

For bringing the moisture down quicker in small pieces for carving, lumber can be placed in a box with stickers between the boards so air can circulate to all sides.Then make an opening on one side place a small fan to blow air across the board .Inside the box use a 60 watt bulb with proper light guard to prevent fire.This will heat the wood up and coupled with air flow will bring the moisture down much quicker Be sure to cut a small exit hole for the more humid air to escape.In winter time shoot for the lower end say 6% and summer 8% in the eastern USA.Using this method you can bring lumber in from outside storage areas such as barns,sheds and have proper EMC so your finished product will stay flatter and develop less defects because of less movement.Also as previous post had mentioned ....treat both sides of the board the same...ie...plane equal amounts of each side, finish applied the same even on backs where not seen,storage.....leaving a board in the shop with one side down and one side to the open air can warp a piece overnight (especially with heat on !).Either place scrap on top to block air flow while work is in progress or sticker with a little weight on top where the air can get to both sides.This hot box method is used a lot by guitar makers to bring down the moisture in top material before and after re-sawing and before they laminate it to their body wood.I hope this helps.
Ben

[pkunk]

Another thing you can do is if the wood is going to be outside and have an oil finish is to finish/oil first, before carving, as the oil will seal the wood. Right after carving, soak the piece again, both sides.

[IM2HAPPI]

Thanks for the information guys. Will try your advice. It might very well be how the guy who we get our wood from kiln dries it. I will go to HD or Lowes and try a piece from there, see how it goes.