Wood Drying

[Willyou]

I just purchased a few pieces of freshly cut juniper lumber for a special project. I have it stacked and stickered in the  enclosed (hot) attic space above the car port. I'm not sure how long it will take to dry and I don't have a moisture meter. However, I have in the past used the oven baking and weighing method of determining moisture content. To keep from having to crawl up into the hot attic to cut pieces for testing from time to time, it would be more convenient to cut some small test pieces ahead of time and retrieve them from the attic one at a time as needed. However, I'm concerned that the small pieces would dry faster than the lumber. Does anyone know if this would work?

[Wild Turkey]

Yep, smaller pieces mean more surface area which means quicker drying.

I got a moister meter at Lowe's, about $20 IIRC. Well worth the cost.

[Willyou]

That was my first thought too. But, I don't know how the moisture travels out of the wood. If it goes in all directions, then that would certainly be true. However, if moisture travels mostly certain pathways, along the grain for instance, then maybe the sample piece size wouldn't matter so much.

[jteneyck]

Freshly cut to me means straight from the log which was from a recently felled tree.  You don't want to dry lumber in a hot space right after it was cut.  It will check, twist, or worse and your lumber will be good for firewood and not much else.  The damage is probably already done on this wood unless you live somewhere the RH is really high.  Next time sticker your freshly cut wood outdoors, at least a foot off the ground, in a shady area.  Cover the top with something to keep the rain off.  In 4 - 6 months 4/4 lumber will usually be ready to bring indoors for further drying.  You want to leave it outdoors until the moisture content is below the fiber saturation point of 28%.   Where I live in NY 4/4 lumber will dry to 12 - 14% outdoors, in about 4 months if I cut it in the Spring, almost twice that if I cut it in late Fall.

John

[Willyou]

I live along the gulf coast where the RH is pretty high. I'm not sure how long the wood had been cut from the log when I got it, but probably only a matter of days. It was still pretty flat with no cracks or checks. It has now been in the attic (hot, but ventilated) for a couple of weeks. I'll have to crawl up there to check closely, but I don't see any signs of twisting yet. Wondering if I should pull it out and find an outdoor place as you describe.

[jteneyck]

.... Wondering if I should pull it out and find an outdoor place as you describe.

At the beginning of the drying cycle you want temps. of maybe 100F and the RH in the 85% range.  The wood can handle hotter and lower RH for short periods of time, but not constant.  Perhaps your attic fulfills these requirements and all will be fine but if it were my wood, I would put it outdoors.  As long as it's out of direct sunlight and covered from the rain not much can go wrong.  If you have PPB down there and that species is susceptible (no clue) then you should spray the wood with Timbor or something similar to prevent them from giving you wormy wood.  

John

[Willyou]

Yeh. That's about right. A thermometer shows the temp in the attic at about 110 F (mid day). A local weather station says the RH is 85.
I bought a small General moisture meter at Lowes earlier today. It says that the wood is a lot drier than I thought (in the teens). Only slightly wetter than the other wood (cherry, oak, walnut, maple) that have been in the shop for several years.

[ianab]

You are correct that small pieces of wood will dry faster.  Water travels much faster along the grain, so exposed end grain dries out much quicker. This is why you might end coat boards with some sort of sealer, to slow that end grain drying and reduce checking. This affects maybe the end 6" of a board, so a 12 inch board will dry out faster than a 12 foot board. 

But Juniper / cedar wood is very fast and "forgiving" to dry. It's hard to mess it up. Other hardwood species like white oak or eucalyptus are much more prone to checking if you dry them too fast.

Another way to judge dryness is jut to weigh a board and note it's weight. Do that each week and you will see it's getting lighter. Eventually it stops loosing water, and that's as dry as it's going to get. Doesn't tell you exactly how dry, but it's at equilibrium with the environment it's in, and that's what really matters. Waiting longer isn't going to change anything.

Edit : Don't worry about PP Beetles attacking Juniper. It's natural oils repel most bugs.

[Willyou]

Thanks for the info. I appreciate all the advice.

[TomFromStLouis]

Juniper, like aromatic eastern redcedar, moves almost not at all when drying. For this reason I would not hesitate to use it right now for any outdoor project. I believe them to be the most stable domestics.