Powderpost beetle holes in pieces for benchtop... can I salvage?

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Forum topic by fitzhugh posted 01-22-2015 03:05 AM 1304 views 0 times favorited 11 replies Add to Favorites Watch
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14 posts in 2760 days

01-22-2015 03:05 AM

Topic tags/keywords: powderpost beetles pest bora-care boracare powderpost beetle question

I just realized, years late, that the holes in the boards for my not yet finished bench top may be something to worry about. They fit the photos and description of powderpost beetle holes, though larger than some descriptions at 1/8” to 1/3”, averaging 1/4” or so. In some cases they are crammed with the powdery frass, others, not. I’m hoping someone can advise me on a way to treat and keep the wood because I’ve put a whole lot of effort and time into them.

Can I safely treat the wood and still use it? Do I need to, or can I take a wait and see, now that I know to actually look? If treated, can I use the bench without health risks, or getting any nasty residue on hands, tools and projects? Do I have to now treat each piece of wood in the shop or can I treat the few visibly damaged ones and take a wait and see approach? I honestly don’t know if the are more holes than before. I can’t check for frass just below holes because I moved stuff to a new location. I can say that the boards a a whole lot dryer now; could the infestation have died off?

I really want to salvage the boards if I can. They came from someone making a log cabin – his test cuts as he learned his new (to him, otherwise old) bandsaw mill. The mill had pretty drastic issues tracking as it passed knots as well as some issue causing severe twist. They started out as about 3 1/4 to 3 1/2 thick by 13 by 66. However, by the time I hand planed away the waves and wind they are just under 2 3/4 thick (that truly was the max size that fit). That was A LOT of shavings! I put a lot of sweat and no small amount of blood into them. I made a couple planes to help, including a 23” wooden try plane to flatten the top. I also had to wait a few years for them to dry out since they started very wet, then wait for space when the room got taken over as not-shop space.

I’ve read Bora-care is better than timbor, penetrates better. I’ve read the msds and it states the toxicity is from ethylene glycol but that it is generally non-irritating. Any input? Also, does the ethylene glycol stick around or evaporate? I’ve read it breaks down quickly in soil and atmosphere – if I interpret correctly I’m safe.

Anybody have any suggestions or advice?
Thank you,

11 replies so far

View Randy_ATX's profile


878 posts in 2442 days

#1 posted 01-22-2015 03:25 AM

Heat will do it. I don’t like using chemicals if there is another way. This previous post may help. Basically build an enclosure and heat it up so internal wood temp gets around 130 degrees for an hour or so.

-- Randy -- Austin, TX by way of Northwest (Woodville), OH

View WDHLT15's profile (online now)


1744 posts in 2476 days

#2 posted 01-22-2015 12:48 PM

The wood needs to be heated to an internal (not air temp) of 130+ degrees for a minimum of 4 hours.

Powderpost beetle holes are very small. If the holes are 1/3” to 1/4” in diameter, it is not powderpost beetles. That would be good. Can you post some pictures?

-- Danny Located in Perry, GA. Forester. Wood-Mizer LT40HD35 Sawmill. Nyle L53 Dehumidification Kiln.

View Nubsnstubs's profile


1288 posts in 1730 days

#3 posted 01-22-2015 01:10 PM

I’d sure hate to meet up with the bug making that 1/3” hole. What ruler are you using to get that dimension? That’s a pretty large bug hole….. jerry (in Tucson)

-- Jerry (in Tucson)

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3194 posts in 1869 days

#4 posted 01-22-2015 01:10 PM

I’d say powder post beetle holes are generally less than 1/8”. Not only that, but they look good. (On a piece intended to be either rustic or shabby chic/romantic/primitive. You don’t want to bring the actual beetles along though.

I had to wash my roof shingles, and used a mixture of outdoor bleach and tsp to do so. I also got some free dunnage timbers (red oak, poplar, hickory), some of which had beetle holes. (Tiny) I sprayed this mixture on the timbers, atop a set of saw horses, wrapped in plastic and allowed them to sit for several days. I’ve not seen any dust. I’ve ripped some into 1” stock, and seen no beetles.

Caveat: I never saw dust from the time I eyeballed them at the job site. They may have had beetles, which made them candidates for dunnage? (Not every piece had beetle holes.) Perhaps the people who supplied the dunnage took steps to eradicate them before shipping? (I did not see them freshly delivered. I received reports of clean, fresh looking timbers from a superintendent who is also a very experienced carpenter, so I tend to think it was fresh sawn, green timbers upon arrival with ppb infestation on site)

I’ve watched these, and have some stickered and stacked, and still haven’t noticed dust in over a month.

Mine was an experiment. Others here are saying extended exposure to 130 degrees. I’d take that route, (although if you don’t have the apparatus in place, it could be time consuming and costly). There are unknowable variables in my tale, so I’m not claiming my absence of dust is a result of that effort, but thought I’d share it anyway.

-- Support woodworking hand models. Buy me a sawstop.

View fitzhugh's profile


14 posts in 2760 days

#5 posted 01-22-2015 11:00 PM

Thanks for all the help and suggestions. Yeah, they are large holes, though using a real ruler and not my vague memory shows most are 1/8”, some 1/4”, a few a bit larger, and there is one area that has smaller holes around 1/16”. There is one gallery that is almost 1/2 at the largest (across, not length).

I agree, I like the holes, just like I like the now-stable cracks. I just want them to stay in these pieces and not move to other stuff!

I don’t have a ready link, but I think I read you may not see dust often. As I understand it the holes you see appear in external surfaces only happen when the larva emerge from the wood (as adults?? to fly off and mate and die). This happens a year or so after the eggs hatch. I’ll look for that information.

Come to think of it, I now think it is pretty clear these holes, or at least most of the larger ones, were there and just exposed when the wood was cut, and not exit holes.

Had to look up ‘dunnage’. Brings to mind a question: I always read that pallets often have good hard wood. Every single pallet I see here in the Bay Area are made of awful, soft, rough, cracking soft pine or similar. Oh well.

Photos of the board I am not going to use – so I stopped while still using the scrub plane. The others are currently covered with my shop stuff and then plastic to prevent construction dust from getting over everything (landlord fixing hidden leak)

These are the larger holes:

And the smaller ones:


PS: The gratuitous bandage shot is due to the obviously dumb idea of putting my new bench grinder on a small wooden folding table and the table on uneven pavement. Of course the table moved (um, I kinda kicked it) just right so the webbing of my thumb got snagged by the course wheel and pulled in. Luckily I got a cheap 6” grinder for $50 and not a nice expensive and actually powerful baldor or the like, as the motor promptly stalled before actually eating my thumb. I got off LUCKY.
Moral of the story? By cheap crap tools, they’re much safer! (maybe you shouldn’t listen to me, and maybe I should have stuck with hand tools only after all)

View Bill White's profile

Bill White

4932 posts in 3961 days

#6 posted 01-22-2015 11:06 PM

Boracare brand treatment for powder post beetles.
I’ve used Borax brand in a solution for the same.
Your infestation looks more like bees.


View Nickdarr's profile


69 posts in 2031 days

#7 posted 01-22-2015 11:17 PM

Carpenter bees or carpenter ants around here leave that sized holes. I have some locust with similar holes. My .02 cents worth.

-- Darren... Hmmmm, I got nothin.

View fitzhugh's profile


14 posts in 2760 days

#8 posted 01-22-2015 11:37 PM

Ok, so if I’ve seen no scary ants or bees in the few years these pieces have been inside I probably don’t have to worry? I would be thrilled if that’s the case! I suddenly worried that the holes I liked in my bench were going to become holes I hate in stuff I make on my bench.

View NinjaAssassin's profile


633 posts in 1725 days

#9 posted 01-22-2015 11:49 PM

Am I incorrect in thinking that filling the holes with epoxy or something similar would solve the problem, assuming one exists?

-- - Billy

View fitzhugh's profile


14 posts in 2760 days

#10 posted 01-23-2015 05:02 AM

Yeah, as I now understand it, at least with the beetles I don’t have, the holes you see are too late to treat, they are exit holes. Apparently bora-care penetrates a few inches and I think is harmless after a short period, but I’m not sure about that harmless part. I know it stays around to kill future larvea for a good while, just don’t know if that means you can feel it or if it messes with tools . I think it may react with aluminum, but don’t recall where I read that.

View WDHLT15's profile (online now)


1744 posts in 2476 days

#11 posted 01-23-2015 01:44 PM

Heating up the wood will prevent the need for chemicals.

-- Danny Located in Perry, GA. Forester. Wood-Mizer LT40HD35 Sawmill. Nyle L53 Dehumidification Kiln.

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