A few years ago a 42" White oak fell on one of my rental properties. To teach it a lesson, I had it quarter sawn and stacked it in my driveway. Today I pulled some of the wood and started making a top for a sideboard for the daughter of my friend. I noticed piles of frass in the stack. Apparently I have Powder Post Beetles Or one of their cousins.
Should I spray now with Boracare? Should I insert the wand of the sprayer into the stack and try to soak them, or should I dismantle the stack and treat each board. If I dismantle the stack should I resticker it or flat pack it? Any other advice?
I'm a firm believer in heat treatment only. I don't have confidence that the spray will kill eggs in the wood. It's shocking how much damage can be inside the wood with only a few little holes in the surface! My friend has basically heated his home with wood that was destroyed in a shed on my Mom's farm.
Heat may kill the existing critters, but will not prevent re-infestation.
Boracol works by works by killing insects gnawing their way in and out of the wood, so once coated, it works also against re-infestation.
The borate itself is not toxic to warm blooded animals - like us - the toxic component is the glycol solvent used to disslove the borate. Once that has evaporated, it's gone.
The first good news, is that their all only in the sapwood of your White Oak, so your heartwood should be fine. Red Oak doesn't have the same insect resistance, so your lucky there.
If it's all 4/4, it should be fine to dead stack it by now if its had good air circulation . If you had some sawn thicker, you ought to cut into some so you can meter the inside.
Some of those critters are mainly interested in the wood while it is moist, so likely got in there right while the stack was new. I know you like to do things on the cheap, so check out how I deal with them. You might also add a internal meat thermometer that you drill a hole into the center of a board but the cable leads outside to the display. You can pick one up at Target for ~$15. It may take a week or two if it's cold outside the tented stack.
How long to wait for a top? While answers here will solve the infestation problem, just how long will it take? I wouldn't want to wait several months for you to find the safe lumber.
The stack is about 8' long and 4' wide and about 8' tall. My stried used to sell hot tub covers and he gave me one. It's sitting on top the pile like a giant hat. I thought about wrapping the pile with a tarp and heating it. I just don't know if I could heat it enough in the winter to do any good. I have a propane blower heater but I am afraid it put out a lot of moisture and there is a fire risk. I want to bake the PPB's, not turn them into charcoal along with the wood.
I could bring it into the house and cook it like you do and the heat would escape into the house. That could be a good idea at this time of year, but a lot of work.
I sterilize turning blanks in an old refrigerator. I have an electric hot plate, with a really big aluminum heat sink I got at the junk yard sitting on the element of the hot plate. Very easy to creep up to the 150 degrees. Some guys that build small kilns, use the heating element and controls from a scrap electric oven. They mount the element on a piece of aluminum plate to get more heating area. Some mount all that in a metal box inside the kiln, and put a fan behind it. Some just hang the plate in the air and put a fan behind it.
I wouldn't try to sterilize the entire stack at one time. Some plywood and shipping blankets make a nice insulated box, or rigid foam with screws and taped joints.
I'd also rip off all the sapwood and damage before you start.
While I’ve done larger stacks, i would suggest that you try to keep it down to smaller batches if maybe 100 bf at first, or until warmer weather. The heat comes up rather slowly as the moisture evaporated, then a little quicker toward the end with this mild heat. You don’t want to take it too fast, which would likely cause small surface checks.
Grew up on a farm where one of the crops was dark fired tobacco. My grandfather was in charge for firing it. He would build small fires under it for days on end and watch a thermometer. The temp in the barn stayed stable for a week or more. At the end, when the moisture was finally gone the temp would rise dramatically. He watched closely for that and at that moment the fires were put out. Otherwise there was a danger of burning the barn down. One did burn.
I had trouble with PPB in some butternut stored in a shed loft and used Timbor (similar to Boracare). I sprayed both sides of each board and restocked them with stickers. The Timbor does not penetrate deeply and does not kill the eggs. Whens the larva emerge, the residue kills them. I also sprayed the other boards in the loft. It worked.
