Kiln Dried Walnut vs. Air Dried Walnut

[cfullen]

Hey guys,

I purchased around 500BF of some beautiful black walnut via craigslist last week.  I have a friend that is in the lumber selling business and he says I need to have it Kiln dried.  He says that I will have catastrophic failure of all my joints if I do not.  Is there any validity in this advise? 

I plan to build an exterior entry door mainly.  The leftover lumber will fuel a few small personal projects.

I do not have direct access to a kiln, but will find one if need be. 

Any advise would be greatly appreciated. 

Thanks,

 

[mouppe]

Well it's possibly true.

If the wood is not dried to a suitable moisture content level, then it could cause problems. So you would have to air-dry it for longer or put it in a kiln if it is too wet.

 

[cfullen]

The stuff is pretty old.  From what the guy told me, it has been drying for around 8 years in northern Ohio when he found it.  I put my moisture meter on it and its around 11%.

 

[deepcreek]

That's nonsense!  Air dried Walnut is generally considered superior to kiln dried (or steamed) Walnut because it retains its natural color and vibrancy.

Wood movement in doors is caused by either excessive initial moisture content in the wood OR ongoing dramatic swings in moisture content.  This is generally due to improper finishing.  Both faces and all four edges need to be finished even on interior doors.  The tops and bottom are often missed.  For exterior doors, dramatic temperature differential between the inside of a house and the exterior can exacerbate the issue.

 

[roblg3]

http://www.woodweb.com/knowledge_base/Woodworking_101_The_Basics.html
This explains it scientifically.

 

[Gary in Texas]

I will agree with deepcreek on this. 

First off, the wood should have or needs to be properly stickered/ stacked to allow air flow when trying.  Depending on thickness of the wood will dictate how long it needs to air dry.  In most cases, probably about two years for green, freshly cut wood.

I've had issues before with kiln dried wood, particularly, if the wood has been dried too fast, it is subject to splitting and basically will no longer be structurely safe or useful.  I have about 6 pieces remaining of some 12/4 Oak, all 8-10 feet in length I bought years ago, and it wasn't until I planed the first pieces that the splitting was noticeable. I've used some of this Oak in past for shop stuff where I'm not concerned with the looks or usage, but no way will I use any of it as part of some furniture I might build.....

 

[tiralie]

The stuff is pretty old.  From what the guy told me, it has been drying for around 8 years in northern Ohio when he found it.  I put my moisture meter on it and its around 11%.

Deepcreek is right.  Air drying is preferable to kiln drying, it just takes longer so it adds expense and price.
11% moisture is ok, it will drop in the house but pretty normal for wood that has been stored outside.
Tim

 

[papasmurff]

Wood needs to be between 6 and 8 per cent moisture or your joints will shrink. If possible bring it into your house stack it under a bed in the spare room use stickers between each level to allow air movement.  You always want to allow wood to air dry before putting it into the kiln for drying.

 

[cfullen]

Thank you for the info guys!  I have it stacked on my racks in my new shop right now.  I will leave it there as long as possible.  This is going to go on my house, and I will post pictures once the project gets started...

 

[Oldwood]

I'm with PappaSmurf on this one. 6 to 8% for hardwoods.

Gerry

 

[roblg3]

Maybe I misunderstood someone, but steaming and kiln drying are 2 completely different and separate things.  Furniture wood should be KILN DRIED to 6-8% humidity.  Air drying isn't going to get it there. 

 

[RJNeal]

I'm in the kiln dry club for furniture wood.
Kiln drying also changes the structure of the cells which makes the wood more stable.
I was working on a walnut mantle, and talked with our cabinet guy about air dried wood. He told me to stay away from the AD wood if I want the 6"x7" x7' long mantle to stay put. The mantle was a built up of three boards with returns.
Rick

 

[Bois de Jour]

Hey Guys - this is a furtherance to an old string from 2014, but if anybody is still on from that time - here is another walnut aging question.  I have a farm in the far East Tennessee mountains.  Somebody planted a grove of about 60 black walnuts years ago on the farm, and grew them straight and limbed up.  Some of them have some good girth (2 feet in diameter).  I want to rough process some square beams out of the heart wood of one of the trees for some table legs that will be 10 inches square, and 31 inches high for eventual finishing at 9 inches square, and about 30 inches high.  What would be the best way to dry the beams (air or kiln) for my purposes, and should the beam be cut down to the  lengths I need, or left intact - for cutting to the desired length later.  Any thoughts would be appreciated.
Thanks!

 

[peter halle]

Although I am not someone who has a sawmill, if you want to make that table sometime within the next 8 or 9 years you will need to kiln dry.  The old rule of thumb was 1 year per inch if air drying.  I would guess that processing your wood to a length of 8 to 10 ft and an inch or so larger than your desired size would shorten your time in the kiln.  You might want to contact companies in your area that operate kiln dryers and make an inquiry for a better answer than I just gave.

Peter

 

[luvmytoolz]

I'm wondering how accurate that is as I've always been a bit dubious on that one year per inch of thickness rule.

A slab of 2" thick Wilga I've had standing on end in the open in my garage the last 2-3 years measured in the high 20's for MC when other slabs were around 12%. And when I worked at the timber mill, and the building suppliers, vendors that air dried timber for making windows, doors, etc, tended to set them and leave them for several years or quite often a lot longer. The only time at the mill we even roughly followed that rule was for construction grade lumber.

 

[jeh]

My only concern would be the possibility of bugs. I had some kiln dried flooring that apparently did not make it to the kill temperature and it had a powder post beetle infestation. Starting noticing dust trails about a month or so in. All had to come out and it could have been messy as the company providing the material and installing it tried to blame it on the house which was BS. I happened to call a lawyer since I was prepared to litigate and by chance it was their company's outside counsel. Received a call a few hours later saying they would cover the replacement cost including installation.

 

[woodbutcherbower]

The rule of thumb I’ve always followed is what I was taught almost 40 years ago during my apprenticeship. Air-dried for exterior work, kiln-dried for interior work. It seemingly makes no difference what finish goes onto the surface or how many coats you apply. I was taught that the kiln-dried material was too dry, suitable only for furniture and other interior work, and that it was therefore prone to large fluctuations when the humidity increased. Seems like the old boy who taught me was right .........

The only time I ever ignored my own rule was a few years ago (Covid) when I couldn’t source air-dried oak anywhere - so I built a front door for a customer using kiln-dried. Four coats of oil-based UV-filtered poly on every surface. I’ve built hundreds of exterior doors, and I never had one which moved as much as this. I was back and forth half a dozen times - trimming, shimming and goofing around. Caveat (maybe) - The wondrous UK = minus 10C in the winter, Biblical rain and storms right now, then up to 35C during the occasional summer, with the RH fluctuating between 65% and 95%.

 

[Michael Kellough]

The rule of thumb I’ve always followed is what I was taught almost 40 years ago during my apprenticeship. Air-dried for exterior work, kiln-dried for interior work. It makes no difference what finish goes onto the surface or how many coats you apply. I was taught that the kiln-dried material was too dry, and that it was therefore prone to large fluctuations when the humidity increased.

The only time I ever ignored my own rule was a few years ago (Covid) when I couldn’t source air-dried oak anywhere - so I built a front door for a customer using kiln-dried. Four coats of oil-based UV-filtered poly on every surface. I’ve built hundreds of exterior doors, and I never had one which moved as much as this. I was back and forth half a dozen times - trimming, shimming and goofing around. Caveat (maybe) - The wondrous UK = -10C in the winter, Biblical rain and storms right now, then up to 35C during the occasional summer .

I wonder if storing the kiln dried stock outdoors (under cover) a few weeks would have made a difference?

 

[woodbutcherbower]

I wonder if storing the kiln dried stock outdoors (under cover) a few weeks would have made a difference?

In this case Michael - I did. Most of it was timber which I'd bought almost a year earlier because the price was right. It had been stored flat in my unheated workshop with each batch of 7-8 lengths separated by battens for air circulation, and covered with a loose-fitting tarpaulin. It ranged in size from 6" x 1" to 4" x 3". The only time I'd ever used kiln-dried prior to this was for internal projects, and this was a salutory lesson learned for sure.