# Kiln dry or cook air-dried Spruce?



## Greg J. (Jun 28, 2012)

I have come into some Norway Spruce (Picea abies) that was milled into 5/4 and 6/4 planks a few months ago from a tree that had been dead for a year. It has been kept in a garage since then. Right now it has 11%-13% MC and it is oozing resin in some places. There are very few visible checks.

Some questions:
What do I need to do to turn this into good wood for furniture (e.g., shoji screen)?
Is it safe to say that it is (or will be) usable for furniture because there probably aren't a lot of invisible checks?
Do I need to get it to ~7% before I use it? I can do this myself by just bringing it indoors and waiting, or...
Do I need to get it kiln dried to ~7% to avoid further checking?
Do I need to get it kiln dried to set the resin, or is there some way I can cook it myself (without cutting it into pieces that would fit in my kitchen oven)? :smile: (I live in a condominium--fortunately with a full basement and garage.)


----------



## jigs-n-fixtures (Apr 28, 2012)

Where are you, and what humidity levels are normal there? 

You will probably have to work some of it before you know for sure, but it is probably fine. 

The USDA, through the Forest Service, Forest Products Lab, publishes a very good book on drying wood, and "Wood as an Engineering Material". Both are available as PDFs on the web. 

I highly recommend that you read them.

Sent from my iPhone using Wood Forum


----------



## Greg J. (Jun 28, 2012)

*Humidity*

I live in SE Michigan. The average outdoor relative humidity in the winter is about 75% and in the summer, 60%. From memory, indoors it is about 30% in the winter and 45% in the summer.

Thanks for the heads up about the publication! I'll read the chapter on drying wood later today. :cool2:


----------



## jigs-n-fixtures (Apr 28, 2012)

I think you are pretty close to where it will stabilize in that environment, if your not already there.

You could cut a few inches off the end of a couple of the boards and try baking them in an oven set on warm, about 140-degrees, overnight and then check the moisture. Leave them setting so air can circulate for a week, and see where the moisture moves to. If it is close to the moisture in your stack, you are there. 

The moisture content for commercial kiln dried SPF framing lumber in the west is 19%.

Sent from my iPhone using Wood Forum


----------



## Greg J. (Jun 28, 2012)

I'll give that a try, thanks. How about stopping the flow of resin (most importantly by the time the wood has become furniture)?


----------



## del schisler (Nov 5, 2009)

Greg J. said:


> I'll give that a try, thanks. How about stopping the flow of resin (most importantly by the time the wood has become furniture)?


setting the pitch is to kiln dry and get temp up to 160 degree's. I did a google search t*emperature* and time for *setting pitch*. February 28 *...* Heat the *wood* to at least 160 F (180 F is often better) for at least 24 hours when the *wood* is dry. *....* I have yet to see DF actually make hard, powdery crystal *sap* like *pine*


----------



## ETWW (Mar 27, 2011)

Greg J. said:


> From memory, indoors it is about 30% in the winter and 45% in the summer.


70 degrees fahrenheit at 30% relative humidity = 6.2% EMC
70 degrees fahrenheit at 45% relative humidity = 8.5% EMC

That indicates your wood should be around 7% MC prior to working it for the minimum amount of seasonal movement. BTW, that's the recommended wood MC for most of the USA.

Del is correct about 160 degrees being the minimum temp to set the pitch. It has the added advantage of killing off any bugs or larvae.


----------

