I purchased a used workbench yesterday and brought it home to my shop. It’s a large maple bench around 8 feet in length and today I began to disassemble the vises etc. for a thorough cleaning and reflattening. To my dismay, I began to notice small round insect holes that seem to be 1 or 2/16 in diameter scattered over several areas of the bench. The bench itself still seems solid and I do not suspect any structural issue. I am attaching photos for reference. Now I am trying to figure out what my next step should be with this bench since I have a good amount of kiln dried hardwood lumber in the vicinity.
The owner originally got the bench from a high end furniture shop he worked at for several years. He had the bench in his home shop for the past couple decades, which was neither temperature or humidity controlled and located in Eastern Pennsylvania. I see at least one area where there is a hole where two boards are joined – which seems to indicate this happened sometime after assembly of the bench. My shop is both temperature and humidity controlled.
So, what, if anything, should I be doing with the bench to prevent any infestation or further damage? Or, did I just purchase expensive firewood!
Replies
My guess , powderpost beetles. Are they likely to still be present? Sure,why not? If you look will you see them? Nope! You can replace offending wood but you won't necessarily know if you got them all. You don't particularly want to import them into your shop/ home either. A shame if it's a nice bench. I would see if you can get an effective poison in your state. I live in California and legally I can't get crap but then in truth you can get absolutely anything,drugs, heavy artilary, plutonium even probably if you've got enough money and not care much about rules. I would think something like boracare ,poison to them but not to you,at least not much. Remove all finish before application. You could take it to an exterminator, someone that does that microwave thing . That would work. I do know in tenting that for powderpost beetles that they about triple the dose above what they do for termites. A place in Georgia,bugspray.com ,has stuff.
If you can build a bag to get it sealed and up on stickers... a nice long ammonia fume soak should do the trick. Big-boy anhydrous, not janitorial or supermarket. I'd follow up with a syringe full of epoxy into the holes.
All of this should be done "out back", not in the house. Once you let the ammonia off-gas it will be non-toxic to bring back inside.
Nice sounding bench score... would love to see a wide view of the whole thing.
By the way boracare is what they use to treat powderpost beetles in log homes. It's basically a borate in a PEG base. The glycol sucks the borate into the wood for deep penetration.
I appreciate the input. I'm going to consult with an exterminator we have used in the past and see what options he has for fumigation or microwave (didn't know that was a thing!). From what I have read, it seems unlikely that sitting in my shop for 48 hours has led to any contamination thus far but not sure how long I want to tempt fate before I get this addressed.
I doubt that the beetles present an immediate threat. Not sure how they propagate--crawl or fly--but presumably they only do it in certain seasons.
I would think your exterminator ought to be able to handle it. If he can't, try painting the holes with mineral spirits, followed up after if off-gases by a dose of epoxy via syringe.
A penetrating epoxy such as Smiths ,very liquid and long time curing might get them but the holes for the most part are not from them going in but from them pushing stuff out. Chasing them through the channels isn't going to have much effect. They spread in all directions and eventually the wood starts to resemble a sponge.
I knew a guy that took over a colonial era springs resort that had been in the family forever and abandoned more or less for 100 years or more. Huge place on 700 acres of virgin forest, for real -untouched! He sanded and refinished the oak floors in a part of the building he was trying to make livable. The next morning across the new finished floors were hundreds of sawdust mounds from beetles. Soon after that he took his family and headed to the west coast. He offered the place to me to live, not to own mind you and I did stay there for a short time. Big ,spooky and cold! That was 40 some years ago and the building is standing abandoned to this day!
Please report back on the outcome. Thanks!
According to https://entomology.ca.uky.edu/ef616, powder post beetles may be killed at 125 -140 deg F, similar to bed bug killing temps. Before Methyl Bromide was banned https://www.epa.gov/ods-phaseout/methyl-bromide it would have been a suitable treatment, although a dangerous option. I have my doubts that any surface treatment is going to kill all of the larvae. I would choose the heat method. Check with an exterminator who treats for bed bugs using whole house heaters that raise the temperature to above 140 degrees F. You will have to build an insulated box to completely surround the workbench, or take it to a house that is being treated if the exterminator will allow that, Keep in mind that any hide glue used in construction of the work bench will liquify at those temps. Most whole house bed bug treatments last 12-24 hours.
A "maybe it will work" idea, since you don't actually know if you have bugs (might just be old holes).. You can buy thin CA glue with a very fine tip applicator and just flood & plug each hole with toothpicks. Check now & then for new holes to get your answer.
StewMac has all of it except maybe the toothpicks.
I bought a live edge walnut slab that was riddled with powder post beetles. Boracare took care of them all.
Are you able to check back with the fellow you bought it from? If he had no problems in 20 years, you're not likely to. As _mj_ says, they could be old holes. I built my top from rip and flip douglas fir that had those holes, 5 years ago. It was in a shed with other boards and no problems with any of it. Finally built the bench last winter and nearly a year in the shop now, still no spread. Maybe I got lucky, but if there isn't new sawdust they are probably gone.