Drying Walnut

[jPell]

I have recently acquired walnut lumber that was milled in the beginning of February of this year and has been in my conditioned shop (stickered and stacked with the ends Anchorsealed) since then. It is mostly 5/4 with some 4/4. I'm finding conflicting information about how long I should let this stuff dry before turning it into furniture. Any input would be greatly appreciated.

[beenthere]

Welcome to the forum.

If your shop is "conditioned" like a house would be (similar temperature), then pull some sample boards from the pile and weigh them every day or so. Plot the weight loss, and when they stay the same weight for 5-10 days, consider them dry for furniture making. It is crude, but if there is good circulation and the pile has been stickered in layers, it should work for you.

This won't work well if you keep your shop 10-20 degree lower than the "room" where you will place the furniture.

[woodman58]

You can pick up a cheap moisture meter at the box stores (HD) for $50

[Den Socling]

One thing I have noticed about drying walnut is that it doesn't all dry at the same rate. If you are going to air-dry only, I would check the MC of each piece separately. And I hate to rain on your parade but you may need to air dry for a long time before the MC is low enough for furniture.

[Left Coast Chris]

I had a similar situation with a stack of walunt in my shop.  It was air dried after sitting in the shop for one summer.  My boards were 5/4 thick and no fan was used and the shop was only intermitantly heated in the winter.  The summers are very hot here.  Often days of 105 to 110 degrees with 15% or lower humidity.   Humidity and heat are the key.

[jPell]

Thanks everyone. Seems as though the most consistent answer to my question is "a long time"    
I've also been told to air dry it for about a year and then toss it into a kiln to take the MC down to where it should be. Seems as though walnut is sort of a pain when it comes to the drying process. I'm not sure I can wait that long. I keep my shop about 10 degrees cooler than the area where the project will call it's final home. I guess we'll have to see how it goes. And... thanks for the welcome beenthere.

[red oaks lumber]

if you have a kiln go ahead and dry it, walnut dries okay from green.

[Dodgy Loner]

A year per inch of thickness is a good general rule of thumb for air-drying lumber. And of course there is no need to kiln dry lumber after it is air-dried, but many people elect to do this and there is nothing wrong with it. I have been building furniture for years and have never used a splinter of kiln-dried lumber. I think the best advice I could give you is to get a moisture meter.  You may be surprised by how quickly the lumber will dry given the right environment - I have used cherry lumber for furniture that has been dried for only three months. The resulting table has been beside my bed for the past five years and is still flat and stable.

[red oaks lumber]

that rule only applies in certain regions of the country. up here air dried moves more than a polatican in a debate.

[SwampDonkey]

3 months won't do it for air drying up here neither. I don't even attempt to use anything unless it's 3 years air dried. I have seen 10 year dried stuff move 3/4" across 24" width. That being said I do not cut to width (across the grain) for several weeks sitting in a heated shop. And it can get mighty warm near the stove where I stack it. Narrow stuff up to 4 inches I still leave an 1/8th. Cherry up here isn't quality stuff. But you can get some short quality pieces. Some is full of gum, and others is clear. Some of it looks included (included sapwood), with a white ring, then pink, then brownish, then white. Funny stuff. I've bought cherry from PA and it wasn't included, but had gum. That being said, the most stable woods I've used is yellow birch, butternut and white pine.

[metalspinner]

I would worry about stacking green lumber in a "conditioned" envirornment.  Slow drying outside is a safe way to air dry green lumber.  A kiln also offers a controlled climate to safely dry lumber. If air is not moved through the stack, mold and mildew may become a problem.  A fan blowing conditioned air through the stack could cause the lumber to dry too quickly causing surface checking.

Walnut, however, is one of those woods that behaves wonderfully - no matter how much you abuse it.   If it is straight grained and stacked and stickered correctly you may get away with drying it inside without major defect.

[Dodgy Loner]

that rule only applies in certain regions of the country. up here air dried moves more than a polatican in a debate.

To what rule do you refer? One year of air-drying per inch of thickness? I'm sure you're right about that - it would be helpful to know where JPell is located to give better advice. In practice, I find that oak is the only lumber I saw that actually takes a full year to dry in our climate. Pine, cherry, walnut, maple etc. generally take 3-6 months.

Also, I doubt that air-dried lumber moves appreciably more in a northern climate than in mine. I have seen a lot of 18th century furniture built in New England that still looks very good because furniture-building techniques were developed to allow for wood to expand and contract with the seasons as it inevitably will. Kiln-dried or air-dried matters not, wood will eventually come into equilibrium with its environment.

[SwampDonkey]

Agreed Dodgy, no stopping it. Still, it seems to move quite a bit at times even after years of air drying. But I also know that air dried wood is not used that quick up here, it's dried for years. Unless kilned. I've seen solid doors on cabinets warp like a barrel even after 3 or 4 years of drying. You could argue construction methods, and your probably right. The ones I've seen where just edge glued or biscuited and not mortise and tenonned. A real gamble with some woods. Need something in the design to counter the tendency to cup.

[WDH]

Nothing wrong with air drying wood as long as you let it reach equilibrium with the end-use environment.  Kiln drying allows that to happen sooner.

[tyb525]

I've used lots of wood that's dried for a year, and sometimes less, without trouble.

The problems occur when the wood then enters a home where the humidity and temp fluctuate frequently and drastically. Kiln drying won't stop that, all it does it get your wood to 6-8%. Who knows what it will change to inside someone's home. I think the key is using a design that can withstand a little movement.

[red oaks lumber]

i'm not doudting your ability to use air dried. only pointing out the fact air drying won't work in all regions of the country. ya you can bring the wood indoors for a couple months to " climateize" but who really is going to do that for every project? not to many. up in northern wisconsin the very best iv'e seen air dried red oak is still 12% how is that dry enough? its not.  homes in the norther part of the country are closed up and heated for 6 months which makes for very dry conditions. then in the summer windows are open letting very moist air back in the house.i have made flooring for people that only had air dried wood even letting the wood acclimate for 5 weeks guess what happened the next winter? small kids could fall in the gaps where the wood shrankup. but kiln dried doesn't do that wonder why? because our climate just isn't good for airdried only.
 not trying to argue just don't want people to think nomatter where they live airdried  lumber is all that is needed because as realitors say location location location is everything

[Ianab]

" ya you can bring the wood indoors for a couple months to " climateize" but who really is going to do that for every project? "

Well basically that's what  you need to do.

It is practical is if you have an inside storage space to finish the air drying and get it down to they 8% region.

You are 100% correct that if you build stuff with 12%+ air dried wood, and then bring it into a house where the equilibrium is around 6%,  then things are going to move. But if you can get it to around 8% by air drying it's going to be about the same as 8% kiln dried.

Ian

[SwampDonkey]

It also goes without saying that your greatest shrinkage is in the initial stages. But, It only shrinks when bound water is lost, people use MC 30% as a rule of thumb. Drying below this causes shrinkage. It's called the fibre saturation point. With shrinkage the fibres are no longer saturated as they loose water. But as pointed out, later on when you've dried it to say 8% the fluctuation between shrinkage in dry air and swelling in the summer and fall results in smaller degrees of movement. Up here on clear cold winter days or nights the RH is around 45%, overcast is  hovering around 75% and when snowing close to 100 %. I have observed this for years. And today was another one of those cold dry days at 45% RH. I have a weather station here, plus you can get the figures on the web for the day. In the house it ranges from 15-40%, depending on whether I heat all day, and higher in the fall. Probably 60-70% because I wouldn't have a fire every day nor all day. I doubt that air drying up here gets below 16% MC, our summer heat is humid. The drier days are the cold fronts that come in with clear blue skies to cool off the air and drops the RH as a consequence. I have simply learned to work in the winter and dry my wood with the shop stove for a few weeks, leave a little extra width. Design for movement. I'm still learning the art, by no means an expert wood worker.  Some profess to be, but I know they still make mistakes.    

[WDH]

I think the key is using a design that can withstand a little movement.

Ty, you are a wise youg man.

[LumberGuy]

I air dried some walnut several years ago to make a sewing table.  The wood was split first, then sawn, and stacked with lots of space for air to circulate around the boards.  I sealed the ends with polyurathane to keep it from end-drying too quick and splitting.  I agree about the moisture meter, it is really helpful when determining if your wood is ready.

[mwigant]

When we talk about humidity, keep in mind it is relative humidity. The actual amount of water vapor that the air can hold air varies with pressure and temperature. A RH of 45% at 30 deg F is much less moisture in the air than a RH of 45% at 80 deg F.

Mike

[SwampDonkey]

Yes, because the dew point is lower in the cold air example than the hot air example.