# air dry v. kiln dry



## woodtick greg (Sep 12, 2011)

I'm probably going to open a can of worms here but I would like to here everyones opinion on this if it hasnt already been discussed. I use air dry lumber almost exclusively and with great success, I find that it works easier and is less brittle. Like with all lumber you need to let it aclimitize and reach an equalibrium in your shop before use but thats no big deal. I think that all wood is always alive and it will constantly move with the changes of the season and projects need to be constructed to allow for this movement. thinks have been built for thousands of years with wood that wasnt kiln dried and alot of it is still around today. I'm sure my furniture will be around long after I'm gone. I'm not sayin one method or the other is better, just that sometimes people get to hung up on one method. One big advantage of kd lumber is bug kill, but i have only had one episode of this and it was wood beatles [not powderpost] was kinda funny, brought some wood inside in the winter to aclimate and when the boards warmed up they hatched! stomped out about a dozen of the little buggers then done. I find that once the wood is dry they usually leave. A friend of mine has a mm that goes down to 10% i think and we tested my ad lumber from my garage and got no reading, less than 10% ? I dunno but my projects dont explode as some people say happens with ad lumber. I do have a 6' by 4' walnut kitchen table with breadboard ends and it moves about 1/4" seasonally. someday if I have the room I will build a kiln just to speed up the process but in the meantime I'll keep useing ad lumber and loving it.
I'm just sayin, what say you?


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## Daren (Oct 14, 2006)

http://www.woodworkingtalk.com/f2/air-dried-vs-kiln-dried-29206/

http://www.woodworkingtalk.com/f26/storing-kiln-dried-wood-20014/




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## woodtick greg (Sep 12, 2011)

thanks daren, read both of the links you left with great interest, I was hopeing you would chime in. do you agree with the statement that ad seems to be easier to work? funny that you really dont like oak, lol. i've kinda replaced ash for oak, doesnt smell so bad when you cut it, lol


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## Daren (Oct 14, 2006)

woodtick greg said:


> do you agree with the statement that ad seems to be easier to work?
> 
> funny that you really dont like oak, lol. i've kinda replaced ash for oak,


I don't really notice a difference between kd and ad when working with it, not in the kind of work I do/the kind of woods I use...but I know guys that do a lot of steam bending (I don't do much) and they only want ad.

Nope, I don't like oak, I've said it here 100 times. I don't like sawmilling it-and will never build anything for myself from it inside furniture wise...In my shop it is used for jigs and such, utilitarian stuff I don't want to waste ''good wood'' on. I don't even try to keep much in stock for sale, when people are looking for oak I send them down the road to the Amish mills, they sell it for $1.50 bft FAS kiln dried (I can't make any money trying to compete with that) I keep a little around for custom woodworking jobs, if the people insist on oak, but don't enjoy working with it. I don't mind white oak for exterior projects, good choice for that...red oak I have little if any use for.


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## ETWW (Mar 27, 2011)

woodtick greg said:


> thinks have been built for thousands of years with wood that wasnt kiln dried and alot of it is still around today.


Actually, very little of it is around today. That's why 18th century or older furniture is so valued...because there isn't a lot of it left. There's also a reason why museums keep their antique furniture in climate controlled environments.

When air drying was the primary method of drying lumber, the homes that the furniture went into weren't air conditioned like modern homes. A modern home will run about 5% - 6% RH in the winter or lower if moisture isn't added. Furniture built with 10% - 12% air-dried lumber will do some funny stuff when it gets into that dry environment. 

Dr. Eugene Wengert, the guru of wood drying estimates that 90% of all the problems he hears about with wood involve moisture. Hoadley says that for those who ignore basic wood-moisture relationships, that estimate is conservative.

Even Garrett Hack, a renown furniture maker who uses air-dried wood exclusively, says that it needs to be brought down to 8% MC or lower before working. He says that while furniture can be built using 10% MC wood, the construction is very difficult. (Hack told me this in an e-mail when I asked about using air-dried wood and acceptable moisture content).

As for workability, unless one uses hand tools extensively, ie, planes and scrapes the surfaces, carves details etc, any difference between kiln dried and air dried wood is probably unnoticeable. I've used a lot of both and can't tell an appreciable difference, even with hand tools. I don't see why there would be a difference in lumber that has been properly kiln-dried to 8% vs lumber that is air dried to 12% and then "acclimated" to 8% inside. Properly is the key word there. Certainly improper drying, by any method, can introduce stresses into wood. I'll even suggest that in many cases, kiln-dried wood has less introduced stress than air-dried because the kiln drying process can be controlled. With air drying, the rate is determined strictly by the weather conditions which are frequently not ideal.

If I'm going to put 100 hours or more (sometimes much more) into a piece of furniture, I want to give it the best chance I can to survive intact for decades without problems. That means using lumber that is at or near the moisture content of the environment where it will be kept. For a modern home, 8% MC is the highest acceptable value.

That's my (rather lengthy) opinion on the subject and if you put $5 with it, you might get a cup of coffee at Starbucks. :smile:


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## woodtick greg (Sep 12, 2011)

etww, you bring up some valid points. I dont think their is much of anything around from the 18th century let alone furniture. I wonder how much of the furniture didnt make it due to inferior glues or finishes, or just poor care after it was made? how much of it was due to wood failure vs joint failure. like museums unless it is stored in a climate controlled environment wood is going to move alot with changes in temp, humidity etc. I do agree with you about the fact that the moisture goal for lumber should be 8% but even after acclimateing indoors for a period of time wood will reabsorb moisture and swell or expand with changes of the seasons and weather humidity changes, here in michigan humidity swings can be drastic. as I stated earlier I have a 6' x 4' black walnut kitchen table that will move 1/4 to 3/8 inch per year, the only time the breadboard ends were flush was when I built it. I dont have anything against kiln dried lumber, and it may be more stable if properly dried {and I think small independant sawyers do a better job than large commercial mills} I'm just sayin that ad lumber has gotten a bad rap vs kd. woodworkers shouldnt be afraid of it just know how to work with it and prepare it, their can also be a cost saveings. I dont sell my ad lumber just use it so that is not why I promote the use of ad lumber. one other pointe is that I ad in a garage and the lumber is very dry, maybe more dry than lumber dried outdoors, less than 10% exact number I dont know due to the fact that I have only been able to test with a meter that goes down to 10%
etww, I apreciate your input and opinion and hope that all of this discussion aids fellow woodworkers weather new to it or veterans.
p.s. all this talk of humidity makes me think i should by a hygrometer for the shop, garage, and house.:smile:


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## HomeBody (Nov 24, 2010)

If you want to see old furniture go to Europe. I went to a museum in Turin, Italy and it was loaded with 16th century furniture that was mostly highly carved walnut. They also had a wood lathe from the 16th century. In the US, we have the "throw away" mentality, over there old stuff seems to be cared for better. Gary


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## slicksqueegie (Feb 9, 2011)

I think any furniture made back in the 16th century has had ample maintenance to allow it to survive. Its not a matter of the US having a "throw away mentality" We (humans) have a natural "want" made things easier and cheaper sacrificing the quality.

Where is IKEA located?:huh:


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## cabinetman (Jul 5, 2007)

Most all the hardwoods I use are kiln dried. I don't have time to wait. Clients have deadlines...I could die tomorrow.












 







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## Flaggfreak (Aug 9, 2011)

The biggest difference I see is that air dried lumber seems to have more color. Kiln dried lumber seems kinda plain.


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## woodtick greg (Sep 12, 2011)

slicksqueege, i agree, most people want it now! fast n cheap, with no concern for true quality or craftsmanship. few people no what the difference is.
cabinetman, I guess if I made my living from woodworking that would be a concern for me to. I would still buy ad lumber but the seller would have to dry it, hello moisture meter. I'm glad I don't have to buy lumber.
flaggman, Hmmm.....I dont know about that, maybe? I think dehumidification kilns save the color, some commercial mills use steam in their drying process and that can wash the color out, especially in walnut but it does darken the sapwood somewhat. I think ad walnut has much better color, jmo:smile: I guess the only way to really know if that is true would be to mill a log and kiln dry half and air dry half and see if their is a difference. does make me wonder though.


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## ETWW (Mar 27, 2011)

woodtick greg said:


> p.s. all this talk of humidity makes me think i should by a hygrometer for the shop, garage, and house.:smile:


A hygrometer (or three) is a very good, inexpensive tool for any serious woodworker. If you know the RH and temperature, you will know the EMC for that environment.

You are correct in thinking that the lumber dried in your garage is drier than that dried outdoors. It doesn't see the near 100% morning RH that is present outdoors. If you heat your garage in winter, that will contribute significantly to the drying rate and ultimate EMC.

There are lots of reasons why most 18th century furniture didn't survive until today but primarily it's due to the normal ravages of time. Not a lot of anything from the 18th century is still around. However, of the surviving furniture, it's easy to see that moisture-related problems have taken a large toll. Many large, single-plank tabletops are warped like a pretzel. Casework has split sides because wood movement was not accommodated in the design. Cross-grain glue joints like M&T's have failed due to either shrinkage of too-green lumber or just seasonal movement. It's really amazing that any of it has survived this long considering the time involved.

If you want to see 18th century (or older) furniture, you don't have to go to Italy to do so, either. While much is in private collections, most larger cities have museums with period furniture displays. In areas like Massachusetts, Connecticutt, Rhode Island, Pennsylvania and New York, there are many museums with 18th century furniture displays. Even Dallas, near where I live, has a respectable collection. 

There's nothing wrong and much right about working exclusively with air-dried lumber as long as it is recognized that it needs to be acclimated to it's ultimate environment prior to construction. Sometimes, that is not easily accomplished, thus many woodworkers convince themselves that using too-wet wood is perfectly acceptable. For some, that may be okay but for those of us who want our furniture to outlive our grandkids, it is not so.


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## Allen Tomaszek (Dec 11, 2010)

I have customers who prefer air dried and others who prefer kiln dried. I'm OK either way. In the end, the wood will acclimate to the environment it ends up in so if you're using air dried you might as well let it acclimate to the shop before using it which just takes some time.

When I dry wood I prefer to let it air dry first before putting it in the kiln. I find I end up with fewer drying defects if I do it that way. Some species like walnut retain their color better when air dried but some retain their color better when kiln dried right away (hard maple sapwood comes to mind).

Whatever way people choose they just need to understand wood moves. As long as they know which way it's going to move from where they're starting out they should be fine.


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