Hi Guys,
I need some advice on drying wood. A friend of mine from Connecticut wants me to build him a bow and use some black walnut that he harvested from a tree from his grandmother's residence. He harvested it this past spring, had it sawed up and it is now drying in the loft of his barn. Some of the boards he cut are 2 - 3 inches thick because he was thinking of using it in bow risers and gun stocks. How long do you think it would take to dry out?
I've never messed with drying wood and always just ordered my wood and lams from some reputable supplier (like Kenny or Big Jim) under the assumption that it was dried enough for glue-up as soon as I got it. I'd hate to build him a bow only to have a piece of walnut in the riser check later as it dried out more.
Any advice would be appreciated.
Thanks,
John
The general belief is wood dries at 1" per year, drying from the center out. With a 2" board it would take 1 year. The longer you let it season the better, more stable it will be.
A lot will have to do with the relative humidity where you live. The wood will hit a M/C equilibrium with the R/H of your area. If you live in a high humidity area the wood will hold more moisture than in an area of low humidity.
Even if you buy dry wood from someone you should let it acclimatize to your environment before you work it. Wood moves as it dries. The more bulk the less movement. Cut it down too early and it can twist or bend.
Most of my experience is with selfbows but wood is wood!
With most American hardwoods, many use the formula of 1 year per 1" plus a year so a 2" piece would really be three years.
Understand that a piece of wood will never dry below the mc of it's existing environment so even if it is in a barn and out of the "weather", it will only get as low as the surrounding mc.
If it were me, I would choose a piece and reduce the size as much as possible making sure to leave plenty of room for warping, twisting, cracking.
Being that it has been drying for a year, it has lost some of the moisture already. Put wood in a paper or Tyvek bag and put in an AC room. Write the date on it and come back in 6 months or so.
Now weight the entire block. Do so every week until you go three weeks without it loosing any weight...voilà! It's ready.
Bigjim
I never complete understood the basis for the rule of thumb, things are definitely different depending on where you live. Growing up building furniture out west with dry, hot summers 1 year per inch from the center out such as Pat describes worked well. Living in the humid mid-atlantic, my current experience is much more in line with Big Jims -- at least one year per inch of total thickness up in my barn rafters, and sometimes another year just to be sure. Reducing it as much as possible makes a huge difference and can really speed things up if you bring it inside a conditioned space.
I like the weight the block technique. How fine are the graduations you're using to determine no further loss Jim? Grams?
Thanks for the advice guys. I also found the 1 year per 1 inch rule of thumb from another source.
I was hoping to have this bow done for him prior to ETAR next year, but it doesn't look like that will be long enough for drying. He understands that may be too soon as well, so we'll probably go with some other woods.
Thanks!