Drying problems

[Ross.m.]

I'm drying a roughed out stave in my house, but I am worried it will become too dry. The highest RH is in my bedroom at about 27% I noticed a big crack on the back of the stave(thankfully not the section I plan to use as the back of the bow). Is the air too dry and that is why it is cracking?

[JW_Halverson]

In a word, yup.

You might wanna put something on the back of the stave to seal it up.  Paint, shellac, polyurethane, Elmer's glue, dang near anything that will dry out and leave a closed surface.

[Ross.m.]

If I put spray paint on I could just sand it off later, right?

[JW_Halverson]

You betcha.

Easier to sand off a coat of paint than to sand out drying checks!

[Ross.m.]

It's cracked pretty bad on the belly, hopefully not too deep. Time to break out the super glue!

[osage outlaw]

What kind of tree is it from?  Did you seal the back or ends? 

[Ross.m.]

I only sealed the ends and it is a hickory

[mikekeswick]

The problem isn't really that the RH is too low.....it's that your wood is too wet to handle a dry environment yet  27% is dreamily low compared to 80% + I have to deal with!
What is causing it to check is the wood on the outside of the stave drying (shrinking) before the inner wood has moved at all.
If I livedwith your RH Iwould reducemy staves down to the bare minimum thickness then keep them in plastic bags until you have lost the majority of the moisture content. Then they will be safe being exposed to 27%.

[dwardo]

The problem isn't really that the RH is too low.....it's that your wood is too wet to handle a dry environment yet  27% is dreamily low compared to 80% + I have to deal with!
What is causing it to check is the wood on the outside of the stave drying (shrinking) before the inner wood has moved at all.
If I livedwith your RH Iwould reducemy staves down to the bare minimum thickness then keep them in plastic bags until you have lost the majority of the moisture content. Then they will be safe being exposed to 27%.

Its not been any lower that 80 for the past six months! Yesterday was the only exception. But I still managed to check some small diameter yew, should have sealed they belly as well as the back. But small diameter stuff anywhere near pith always seems more problematic,

[George Tsoukalas]

The moisture from the wood has to leave from somewhere. If it leaves too fast the wood cracks.
We don't want it to leave from the back or the ends so we seal the ends. We can leave the bark on or remove it.
Whitewoods are best cut during the growing season when the bark pops off easily.
I generally don't bother to seal the back of a whitewood because growing seasons in NH are pretty humid, believe it or not so the moisture does not leave too quickly.

Osage, the locusts and mulberry are heartwoods where the bark should be removed down to heartwood for a back so the bark can be left on unless the presence of insects is seen. Remove it and seal the back and ends

jawge

[Don Case]

Air movement is also a big factor. Still air doesn't dry things. Moving air does. SteveB puts his staves in an old sleeping bag. Works very much like a plastic bag, just not as extreme. If the air ain't moving the humidity (from the stave) builds up around it, slowing the evaporation. You want to start with low evaporation (high RH, low temp and low air movement) and as the wood dries over weeks you want to move to high evaporation (low RH, higher temp and more air movement). Don't try to dry it too fast, it's going to take weeks, probably months, possibly a year depending on the species of wood. I started in this hobby last summer and I'm just now getting a couple of staves I can work. Waiting is tough.
Don