Is my Engelmann Spruce ready?

[Steve Rolig]

In April of 2012 I was able to harvest some Engelmann Spruce. It was immediately split into wedges and de-barked. Starting a month (and up to 5 months) later it was re-split and squared up into billets 1 to 3 inches thick. Those billets have been in my shop since then, usually 30 - 45% humidity level. Over the last year I have periodically weighed them and by mid summer the weights stabilized and actually after a very wet july - september here in Colorado some slightly increased in weight, now back to there lower weights. Over the last few weeks I have re-sawn a few of the billets (the thinest ones cut into billets in july '12) and the tops seem as dry as any wood I've used. The question is, is it OK to start building with them? This is the first wood I have actually harvested myself so am very excited to build with it. So what do you all think, have I waited long enough? Thanks for any opinions.
Steve

[Alan Carruth]

The usual rule of thumb is one year for every inch of thickness, but I think that's predicated on the notion that the wood is stored outdoors, or in a covered but unheated shed; indoors would be quicker in some ways.

I think there's a difference between 'dry' and 'cured' though. All wood has at least some built-in stress which tends to work itself out over time. The longer you wait, and the more moisture cycling the wood goes through, the more of that stress it can work out. In that sense, storring it indoors under more or less constant R.H. might actually work against you. OTOH, this sort of stress relief might take years, and you have to be realistic. I did use some 'local' spruce for a violin top only a year or so after cutting it, and had no problems, so it can work.

[Michael Lewis]

I think it is probably ready to work. Base that on the weight stabilized. Alan is correct that multiple cyclings of the seasons tend to stabilize the wood more, but it should be good now. You can try the Taylor trick of baking the wood in a 200 degree oven for a while to really dry it out and force the stabilization process. This works well enough on engelmann but less well on some other varieties. I just air dry my wood and let it go at that.

[Clay Schaeffer]

In my part of the country (Mid Atlantic States) storing the wood indoors will "cycle" the wood more than storing it outdoors. Indoor relative humidity in a heated room will change quite a bit as the outdoor temperature changes from warm days to cool nights. An average air change rate for the typical house would be 1 complete change of air per hour. Although the relative humidity might remain fairly constant outdoors (although this isn't usually the case) as the temperature differential changes the indoor humidity will change. Colorado, being on the dry side, the humidity fluctuations are probably much less than here in the sultry semi-South.
I think Michael's suggestion to bake the wood is a good one. I have read that the wood after heating will shrink some and not regain it's former size . To me this would indicate that it is reacting less to humidity changes.

[Chuck Tweedy]

I've baked many Engelmann tops.
It will drive some sap to the surface and dry it to little beads, but it does not change the color or other obvious features of the wood - I've not done any before/after measurements to confirm any specifics.
What I can say is that it has not had any bad effects, and none of these tops have ever cracked (about 8 tops over the past 10 years or so).

Disclaimer - All these tops were purchased and more than likely older than your wood.

[Steve Rolig]

Thanks for the feedback guys. I was out of town over the weekend (babysitting the grand kids) With no time for the internet.
I might try the baking idea, haven't decided yet. If I get the "little beads" perhaps not dry enough. Also, how long do you recommend baking a top set?

[Chuck Tweedy]

The little beads of sap come out of wood that is dry for many years, so I don't think it is a concern if it shows up on your wood. I've read that softwood sap stays liquid in the wood for many years if it is not cooked. I've certainly witnessed this first hand with Doug fir. And of course with baked tops.

Bake the top in its raw state, un-joined, for at least half-hour at 200 F (not C).
I just leave them in for an hour, and then turn the heat off to let it cool slowly. Like annealing steel - not that it is the same process at all.