Air drying and insect questions

I'm a relative novice to intermediate woodworker and have a couple drying questions. I've been researching here and am getting a little overwhelmed by the amount and variety of information. So please bear with me.

I just got some very inexpensive black walnut live edge slabs. Most are about 1" thick. They have been air dried thus far. I don't have a moisture meter yet but will be getting one soon. I plan to use them for small projects like cutting boards. I've read numerous posts on how to sticker them, etc. so my basic question is how dry is dry enough?

On a much more important question, I also have a 3" thick white oak slab I got about a year ago which I intend to make a bench out of. Also air dried. In my naivete, I brought it into my unfinished basement to store. I did not consider the possibility of bringing in insects. There are definitely small holes that to me, look like they may be insect damage. I believe they were there when i got the slab but I don't know if they have increased over time in my basement. In other words, I don't know if I brought live, wood insects into my basement.

So my questions are:

Should I be freaking out at my stupidity of bringing possibly infected would into my basement?
What should I do to both the white oak and black walnut if I want to air dry it in my basement to ensure that I don't put my home at risk?

I realize there's only so much an online forum can help in this situation but everyone here knows more about it than I do, so it's a start.

Thanks for the help.

maybe use a plastic sheet that will cover all of it without to many seams and use a few bug bombs underneath maybe even a coupla times .the wood should have air space between each one so the gas could get to most of it, this is just a guess on a solution

Some people will spray a borax solution to help with bugs. The only bugs I know to be a problem in dried lumber are powder post beetles. As far as what's dry enough, wood will maintain equilibrium moisture content regardless of how it was dried. EMC varies, it's going to higher in coastal S. Carolina than in Albuquerque for instance.

Tom, the only 100% sure method for killing powder post beetles in lumber is heat sterilization. I am a miller and kiln operator and this is a topic that I am knowledgeable in.

Pin-hole size exit holes in oak are usually caused by either powderpost beetles or ambrosia beetles. If ambrosia, they will not survive in dry lumber so you would have dodged a bullet. However, if PPB then most likely your lumber is still infected. To determine which, look at the exit holes under magnification. If there is a black ring around the perimeter of the hole, then you "had" ambrosia beetles. If there is no black ring, then you "have" powderpost beetles, and yes they can infect other lumber in your house.

You can either take your lumber to a kiln operator and have them run it through a sterilization cycle or you can do it yourself at home using a simple sterilization chamber built from foam board and a space heater. There was an article in FWW magazine in the November 2008 issue that will walk you through the process. If you send me a pm with your e-mail address, I'll send you a copy of the article.

If the 4/4 BW has been milled for more than 9 months and has been stickered, odds are that it dry. The 3" oak will require another 18 - 24 months of air drying at a minimum. It is never a good idea to rewet dry lumber as this can lead to surface checking. Considering where your oak is in the drying stage, it is also still too green to sterilize it w/o causing internal honeycomb.

If it were me, I would heat sterilize the BW and use Boracare on your oak (unless the signs are clear that the exit holes were from ambrosia beetles).

What temp and duration would you suggest for PPB. I have demo'ed an old house and the lumber that shows either present/past infestation. Hope this not a derail. Thanks

it is just a guess but I think 140 f. for a 3 to 4 days should do it

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Originally Posted by david privett

it is just a guess but I think 140 f. for a 3 to 4 days should do it

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A local mill said 160 for 12 hours. I wonder if that high temp would lead to distortion.

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Originally Posted by Adam Henderson

What temp and duration would you suggest for PPB. I have demo'ed an old house and the lumber that shows either present/past infestation. Hope this not a derail. Thanks

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USDA Kiln operators specs call for heating the lumber until it is 133F or higher throughout and holding it there for 30 minutes. Typically at the end of a kiln cycle (low temp DH kilns) the operator will turn the temp up to 150F and leave it there for 8 hours in order to sterilize. If the kiln is full of thick lumber (12/4 or greater), the time is increased in order to allow the temperature to permeate throughout the lumber.

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Originally Posted by Scott T Smith

USDA Kiln operators specs call for heating the lumber until it is 133F or higher throughout and holding it there for 30 minutes. Typically at the end of a kiln cycle (low temp DH kilns) the operator will turn the temp up to 150F and leave it there for 8 hours in order to sterilize. If the kiln is full of thick lumber (12/4 or greater), the time is increased in order to allow the temperature to permeate throughout the lumber.

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Thank you for the informative reply. The house was built in the late 1800's and I salvaged everything that was useable. (Wide plank heart pine boards, studs, rafters, floor joists, purlins etc...) It is all sorted, stickered and ready to load and haul to the kiln. I'm going to go with it. I would rather sustain some distortion in the lumber than introduce ppb's into my brand new shop and subsequent projects I intend to build. I am new to wood working and I am finding out that there is alot to learn when working with old wood. Thanks again.

The 150 degree temp at the end of the kiln drying cycle does not distort my lumber because the lumber is dry, and dry lumber does not distort.

That is great to hear. Thank you. I spent a lot of time, energy and effort to salvage this old wood and do not want to "shoot myself in the foot". Thanks again.