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air drying vs. kiln drying lumber

 
paul wheaton
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Location: missoula, montana (zone 4)
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I've heard that air drying works great for conifers, but for the rest you really need to do kiln drying.

And then Mark Vander Meer tells me that air drying is actually the best for all woods!

 
paul wheaton
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Posts: 19441
Location: missoula, montana (zone 4)
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Luke Townsley
Posts: 131
Location: Dugger, IN Zone 6a
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I prefer to work with air dried wood. Here is a discussion on the matter from one of my favorite woodworkers.
http://www.fullchisel.com/blog/?p=393

Also all kiln dried wood is not equal. Cooking it at 185 degrees F is a lot different than cooking it at 120 degrees. Letting it air dry for a time and then putting it in a kiln at low temperature with controlled humidity to finish it off, and then letting it stabilize to ambient humidity is a lot like air drying

Kiln drying southern yellow pine (I believe it has to get over 185 degrees for a time) cooks the resin and makes it hard. Otherwise, it will never harden. Whether or not that is good is a whole other debate.

There are some tropical woods that are said to be extremely difficult to get dry without a kiln.

Kiln drying serves to speed the process up. When used to "finish" wood, it can help ensure a predetermined moisture level.

Some woodworkers such as luthiers may let their wood air dry for a decade or more before using it.

 
                  
Posts: 59
Location: NW Ontario
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Some woodworkers such as luthiers may let their wood air dry for a decade or more before using it.

Wow. Talk about planning.
 
                        
Posts: 278
Location: Iowa, border of regions 5 and 6
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Old hammy wrote:
Wow. Talk about planning.


That's not all.  I remember reading (although I'm too lazy and tired now to look up the exact references) of wood carvers who would bend young trees into the desired shapes.  That way when the tree grew large enough to use, the carver could work along the grain of the wood, making the carving very strong.
 
Luke Townsley
Posts: 131
Location: Dugger, IN Zone 6a
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This video might on woodtreks.com be of interest to someone interested in air dried wood:
http://woodtreks.com/how-to-air-dry-lumber-stack-it-and-check-for-moisture/336/
 
Wyatt Smith
Posts: 111
Location: Midwest zone 6
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So are the logs sawn up green?

I've tried several ways to air dry round timber and had serious splitting. 

I haven't had as much issues with sawn lumber checking, but it sounds like their wedge and weight system is really good. 
 
Luke Townsley
Posts: 131
Location: Dugger, IN Zone 6a
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Round logs almost invariably split regardless of how they are dried due to how wood shrinks as it dries. Most species shrink about twice as much with the grain as across the grain and imperceptibly along the length of the board.

Quartersawn lumber normally shrinks less across its width than rift sawn which shrinks less than flat sawn. There may be a few species that won't split particularly in the smaller trunk sizes.

What you can do is split or saw a log in half or possibly make a cut down to the center of the log which will open up as it dries.

Logs are sawn green because they are easier to cut and because it makes the wood easier and faster to dry. My understanding is that logs with the bark on won't dry significantly except through the end grain.
 
                                                                    
Posts: 114
Location: Nashville, Tennessee, USA
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I am a 4 decade wood worker and own a sawmill.

Air dried is the best but also the most time consuming / expensive.

Trees cut in the winter check/crack less than those cut in the summer.

The goal is to dry the wood very slowly right after it is cut.

Heat is what accellerates drying becaus hot air absorbs water.

So, best to cut and beging drying in winter. 

Cabinet makers and those that consume a lot of wood usually have to buy kiln dried wood.
This is because high volume  suppliers do not have the room to air dry stock for a couple of years.  Wood takes up a lot of valuable space.


 
I agree. Here's the link: http://richsoil.com/email
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