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Insecticide for green lumber

3758 Views 10 Replies 8 Participants Last post by  WDHLT15
About a month ago my brother and I split some milling and had 1800 bd ft of oak milled from some logs I got from a coworker. We have it stacked and air drying in the shed but want to make sure it doesn't get any insect damage. Any recommendations on anything won't damage the wood? It will obviously be planed down before use but I'm a little concerned about oil based insecticides staining deeper into the lumber. Is that a valid concern? Pest control guy had his monthly visit at work today so I asked him and he recommended Termidor (a.i. Fipronil) but he didn't know about the staining of the wood. Anybody have something they've used that worked for them?
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Boric acid was first registered in the US as an insecticide in 1948 for control of cockroaches, termites, fire ants, fleas, silverfish, and many other insects. The product is generally considered to be safe to use in household kitchens to control cockroaches and ants. It acts as a stomach poison affecting the insect's metabolism, and the dry powder is abrasive to the insects' exoskeletons. Boric acid also has the reputation as "the gift that keeps on killing" in that roaches that cross over lightly dusted areas do not die immediately, but that the effect is like shards of glass cutting them apart. This often allows a roach to go back to the nest where it soon dies. Cockroaches, being cannibalistic, eat others killed by contact or consumption of boric acid, consuming the powder trapped in the dead roach and killing them, too.
+1000 on the boric acid.
Very safe, its in toothpaste and all kinds of things.
Was over run with roaches around my shop and now don't have ANY.
Buy the cheap roach powder that has a high percentage of boric acid and dust it on the lumber or you can order it online.
Yes I agree! I'm a pharmacist and before I retired I used to sell this by the pound all the time. If you can't find it go to an independent pharmacy and ask the pharmacist to order it for you. For the use you're going for you could probably make a solution out of it and just use a pump up sprayer to apply it. I have about 4 lbs. of it in the basement that I bought before I sold my store for future use. No ants or bugs here and the dog can eat it he wants (they don't by the way) and it won't hurt him.
Disodium octaborate tetrahydrate. Google it.

I treated about 2000 bf of 4/4 rough sawn hardwood with Tim-bor to halt a powder post beetle infestation. I used three 25# buckets of Tim-bor, mixing it at 15% per instructions for an active infestation. As I recall, a 10% solution is recommended as a preventative measure.

I was quite an undertaking. Boards were placed side by side about 2" apart on a tarp. The surface, edges and ends were sprayed until the solution began puddling on the lumber. The lumber was flipped over and the opposite face similarly sprayed. Another set of boards were placed on top of the just-sprayed boards and that set of boards was treated. I continued stacking and spraying until the stack was about 18" high. The treated boards were then stacked and stickered out of the weather. Rain will wash off the treatment.

I have since used the lumber treated with Tim-bor. While I am not sure it is necessary, a wire brush was used to loosen the Tim-bor crystals on both faces and each edge. A soft bristle bush was then used to brush away the loose debris. This process was performed outdoors after I discovered it made a mess and gave me some sinus problems (lasting a couple of days) when done indoors.

The wire brush cleaning step before milling the rough sawn lumber to dimension was done for two reasons. The first reason is that I wanted to minimize any dulling of the cuttings on the jointer and the planer. The second reason was to minimize Tim-bor dust that could invade the shop. While Tim-bor is a fairly "safe" insecticide, I figure it is best to avoid breathing it.

From what I have read about Tim-bor, it does no penetrate deeply into the wood. I found that this claim is probably true since milling 4/4 lumber to ¾" offers uncontaminated wood which takes urethane like a Tim-bor untreated board would. I have not used any other finishes, but doubt any Tim-bor related issues would arise.

I considered Bora-Care, which features an additive that claims to promote deeper penetration of the borate into the wood. However, since it was more expensive and I did not know to what extent, if any, it would remain in milled lumber, I went with Tim-bor. Either way, treating 1800 board feet of lumber is expensive, laborious, and otherwise as much fun as a trip to the dentist.
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Timbor is 98% disodium octaborate tetrahydrate.
I use Boracare
Another vote for boracare

They make a boracare w/ mold prevention too that's a great option if the shed doesn't get ideal airflow
You do not need boracare to spray green lumber to prevent beetle infestation. It is more expensive and is generally used to treat wood that is already infested. The disodium octaborate tetrahydrate, which is the primary ingredient in boracare, will prevent infestation and for a lower cost. One brand name of disodium octaborate tetrahydrate is Timbor.
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