Do Borate Treatments Interfere with Finishing?

Advice on using a borate insecticide before finishing wood. February 1, 2015

I have about 15 slabs of walnut and pecan under tarps at my shop. Powder post beetles have emerged from some of the pecan this spring, so I have to assume that everything is infested. I was going to treat with Bora-Care, but I am concerned that it will ruin the color or ability to finish the wood. Does anyone have experience with this product? Or have alternative advice for dealing with powder post beetles?

Forum Responses
(Finishing Forum)
From Contributor R:
I canít really answer your question as I have never used it. In the past we have brought furniture and logs to a fumigator. Brought the items in on a Friday and picked them up on Monday. I did not notice any odors or color change in the various pieces we brought to them. Mind you itís been a few years since doing this so maybe things have changed in the world of fumigation.

From contributor A:
I have been using Bora-Care for a little over a year now, mainly for termite prevention. We apply it diluted 1:1 with water. Since we have been using it we have seen no type of wood discoloration and it does not seem to affect our finishes, which are usually clear or pigmented conversion varnishes. It does however leave a very salty residue behind after it dries about 24 hours later. This is usually cleared off during the sanding process as we apply Bora-Care to wood before any type of prep work begins on the wood, whether plywood or hardwood. Just to minimize the probability of any negative interaction with the finishes, we only apply the Bora-Care to the side of the wood that is not going to be used, or the side that would be used/seen less. Like in the case of the wood countertop we would only apply to the underside. According to Bora-Care's specs, their product is 'supposed' to be able to penetrate up to 3" of wood thickness so you should be ok. This is why we give it at least one or even two days to soak into the wood before we start sanding.

From contributor G:
I may be wrong, hopefully the Doc will chime in, but the only way to really kill these buggers is heat. The Bora-Care will kill as they emerge. I would never use infected wood for the liability issue alone.

From contributor A:
To contributor G: Are you referring to termites or beetles? According to Bora-Care once these 'buggers' eat any of the treated wood, they will die a slow death. Once the rest of the colony finds out itís poison wood they supposedly donít mess with it anymore. I know since I have started using it I have seen dead termites near the wood and on the wood but none in the wood.

From Gene Wengert, forum technical advisor:
Previous comments are correct. The depth of penetration of any borate product is very important, unless the insect eats the treated wood then there is no benefit in treating. Unfortunately, powerderpost beetles can eat inside the wood for a year or more, making tunnels without exiting. To get the treatment deep into the wood requires soaking the wood for many days. In your case, however, once the wood is dry (PPB require drier wood), then rewetting the wood is usually not a good idea. So fumigation (expensive as it must be done by a commercial, licensed company due to the dangerous chemicals used) and heating to 133 F are the two options for dry wood, with heating being the most practical in most cases.

In most of the U.S., the termites we have are subterranean, so ground contact is required. Hence, termite protection is seldom an issue in the U.S. for hardwoods as most hardwoods are used above ground (furniture, cabinets, etc.). If you see the holes, that means the PPB has left the wood and is breeding and looking for a new home to lay eggs. So, if you see PPB in your shop, you can have a big problem indeed. Because the insect will be inside the wood for a year or so, often the problem is not seen until the customer gets the finished product.