Woodworm advice

[NDRiley]

Morning All,

I’m currently making a small console table using air dried timber that the client has provided. Following machining I’ve noticed a few woodworm exit holes. This is by no means extensive - perhaps 3 or 4 holes in the whole piece. What would you do?!

1: ignore and carry on
2: point out to the client and carry on
3: apply a woodworm treatment to all components and carry on - if so what and how does that effect final applied finish?
4: give up and use for firewood
5: other

Many thanks

 

[Daniel2]

Personally, I would do a combination of 2 & 3.
I use Xylophene (in France), which wouldn't have any effect on the
choice of final finish.
HTH,
Daniel

 

[Chris152]

I bring air-dried wood into the heated house for a while before using, to drive the moisture content below (I think) 12%, at which they can't survive. Do you know the MC of the wood you're using?
ps I don't tend to do this in Spring.

 

[Cabinetman]

I bring air-dried wood into the heated house for a while before using, to drive the moisture content below (I think) 12%, at which they can't survive. Do you know the MC of the wood you're using?
ps I don't tend to do this in Spring.

I don’t think that’s quite right Chris, I have had woodworm emerge from very dry timber, (two instances where the wood was kiln dried from my local yard, which I always thought killed woodworm ) and usually mid summer, they probably prefer damper timber but they can survive and keep chewing in dry timber, but I’m not an expert. Ian

 

[Chris152]

I don’t think that’s quite right Chris, I have had woodworm emerge from very dry timber, (two instances where the wood was kiln dried from my local yard, which I always thought killed woodworm ) and usually mid summer, they probably prefer damper timber but they can survive and keep chewing in dry timber, but I’m not an expert. Ian

I was remembering Richard's comments here:
https://www.ukworkshop.co.uk/threads/woodworm.106382/(scroll down a bit, after my musings...: 'As others have said, common furniture beetle cannot survive in dry wood, i.e., below about 12% MC, so any wood used in structures in a reasonably modern residential building subjected to decent climate control measures is highly unlikely to harbour common furniture beetle.')
But like you, I'm no expert!
eta - Plus, working with wood with higher moisture could result in problematic movement once it comes into a heated house? Again, that's just a principle I've worked to.

 

[Cabinetman]

Thanks Chris that was very informative, I built my bed from kilndried American ash, and brought it home to my warm dry house whereupon within six months there were 12 holes in one of the pieces of wood I used, I found all the beatles on the windowsill in the ensuite right next door, I think they flew towards the light. So let’s hope you’re right and that they didn’t lay eggs back into their exit holes and if they did it’s too dry and warm to survive. I can assure you that the ones that landed on the windowsill didn’t survive! Ian
Edit, I should’ve said that the timber was in my dry warm workshop for two years prior to building the bed.

 

[NDRiley]

Many thanks to everyone for your advice - much appreciated. I have had the timber for a number of months and rough cut out the components before storing indoors for that time. Moisture content is c.12% according to my meter so hopefully that should help the situation. I will also treat it as Daniel suggested to give additional reassurance to the client.

Thanks all

 

[Sgian Dubh]

Thanks Chris that was very informative, I built my bed from kilndried American ash, and brought it home to my warm dry house whereupon within six months there were 12 holes in one of the pieces of wood I used, I found all the beatles on the windowsill in the ensuite right next door,
Edit, I should’ve said that the timber was in my dry warm workshop for two years prior to building the bed.

I'd have to say that to see common furniture beetle exit holes in American ash kilned to ±7% MC (the North American target MC) appears anomalous. As has been mentioned it's considered by those in the know to be virtually impossible for the freshly hatched larvae of this bug to survive in wood at 12 % MC or lower. Assuming that to be scientific certainty, and I have no reason to question the scientists/entomologists who came up with that number, the questions have to be:

1. Did the wood gain enough moisture after kilning to sustain the larvae of a fresh infestation?
2. How might the adult beetle have been able to find the wood in a damp enough atmosphere that it was encouraged to lay the eggs in the first place? The adult beetle prefers cool damp conditions (atmospheric RH of 55% or greater).
3. Could the infestation have been something other than Anobium punctatum, such as powder post beetle (Lyctus)? Lyctus is rare in the UK, but it is sometimes imported in timbers from areas where it is common, such as the USA. Common furniture beetle larval exit holes are 2 -3 mm in diameter, whereas Lyctus larvae bore an exit hole only about 1.5 mm in diameter.

If you did find common furniture beetles and their exit holes I'd say there's highly likely to have been a time between kilning and the discovery where the wood was wet enough and the adult insect had the opportunity, or opportunities, to lay eggs. But how that can be reconciled with your description of the wood's storage in your dry warm workshop, then its use and six months later finding exit holes and live beetles in an adjoining room is a mystery. I can only wonder where and how the wood was stored between its kilning and you buying it, and it crosses my mind that perhaps your workshop may not always be as dry and warm as you think (and naturally I have no idea on that score).

Anyway, it's an interesting conundrum or anomaly, and I can't offer a definitive or authoritative answer. Slainte.

 

[M_Chavez]

I've had a couple old violin soundboard blanks given to me a while ago and one of them had two worm exit holes.
When I've bandsawed through them, I found that both blanks were completely bored out by the worm - you could even track the worms' growth by the tunnels getting wider and wider. Worm holes are a bit like an iceberg - you don't see the whole picture of what's underneath.
One of the worms was still in there (a big fat chunky one) and got decapitated by the bandsaw.
If memory serves me right, it takes a few years (?) for the buggers to hatch, so they have plenty of time to munch on the wood.

 

[Cabinetman]

Hi Richard, thank you for that informative reply, my workshop is dry and usually kept to about 12°c. This wormy bit of wood was cut off for firewood and it shows the tunnel going across its surface and that tells me that it was done before the wood was cut into boards and then it would have been kiln dried, The pinholes and the tunnel are all around about 1 mm across so I think what you are saying Richard is right and they are American interlopers, I think I must just have been unlucky with one piece on my bed and they managed to survive somehow, maybe it wasn’t dried properly in the states? Ian

 

[Sgian Dubh]

Hi Richard, thank you for that informative reply, my workshop is dry and usually kept to about 12°c. This wormy bit of wood was cut off for firewood and it shows the tunnel going across its surface and that tells me that it was done before the wood was cut into boards and then it would have been kiln dried, The pinholes and the tunnel are all around about 1 mm across so I think what you are saying Richard is right and they are American interlopers, I think I must just have been unlucky with one piece on my bed and they managed to survive somehow, maybe it wasn’t dried properly in the states? Ian

Powder post beetle (Lyctus) is fond of ash. There are stories from North America of boarded ash stock significantly attacked by the beetle, as well as severe attacks on felled sawlogs and boarded up and air dried stock. If your wood was carrying lyctus larvae, I suspect the infestation occurred some time between kilning and export to the UK. The larval stage of this species in the right circumstances, i.e., dry wood indoors, can last between about two and sometimes up to five years.

I'm certainly not going to tell you that it's almost certain your wood was infected by powder post beetle, but the exit holes in your image of the affected ash suggest a smaller exit hole, ~1 - 1.5 mm, than the 2 - 3 mm hole a common furniture beetle creates.

This link might be worth a read. You'll note that the author has released the linked factsheet via a reputable organisation, i.e., Texas A & M University, which suggests he's not a self-promoting know-nothing inexpert entomologist, or similar ... which might be the description I should really attach to myself, ha ha. (I'm really not an entomologist; I've simply done a bit of research into a few timber tech issues.) Slainte.

 

[TheTiddles]

I’ve had two strips of kiln dried beech get exit holes after edging MDF, I guess they took up residence in the garage after drying and I didn’t notice when making.

I’d treat the timber, tell the client and see what risk they fancy taking

Aidan

 

[NDRiley]

Thanks very much everyone for your input. It’s been really helpful.

The client has agreed for me to treat the timbers so the project proceeds in this case. M/C is now c. 12% and the final piece will be stored in a centrally heated house so I’m reasonably confident the that the problem will not get worse.

The client also has a further stack of the same timber (FYI it’s monkey puzzle) waiting for the next project. Last time I measured it M/C was 25 to 28%. It’s stored outside but covered from above with boards. He’s wondering whether to spray the whole lot with woodworm treatment. Any thoughts on whether this would be worthwhile?

 

[TheTiddles]

I wasn’t aware monkeypuzzle was much use beyond novelty turnings with those huge knot rings. What’s it like to work with?
Aidan

 

[NDRiley]

I wasn’t aware monkeypuzzle was much use beyond novelty turnings with those huge knot rings. What’s it like to work with?
Aidan

Me neither! This is a slightly unusual one in that the tree was felled on the client’s property and for sentimental reasons he had it milled on site in order to make something out of. I got that commission. The timber itself is pretty soft and any changes in grain direction result in tear out when machining/planing

so care is required. Due to the large and numerous knots it lends itself to something chunky rather than anything too fine or intricate. The proliferation of the knots also means it’s virtually impossible to get any clean, knot free boards without wasting an awful lot of wood.

Embracing these characteristics we’ve decided on a relatively chunky live edge console table with robust proportions. Hopefully this should show off the attractive features of the timber (the knot/wood contrast is pretty dramatic) but avoid its inherent limitations.

Attached are a few picks of a test piece I machined and finished as a kind of proof of concept. Not everyone’s cup of tea perhaps but definitely something out of the ordinary!

Hope that answers your question but if not please let me know.

 

[TheTiddles]

Thank you! Yes, it’s quite a look

 

[Cabinetman]

Yes well done for working with the client and trying to point out the pitfalls whilst ending up with something that is doable and he is happy with. Quite agree use the knots and use/employ them rather than trying to work around them, mind you I’m glad it’s you not me! it’s not called a monkey puzzle tree for nothing. Ian

 

[Sgian Dubh]

Me neither! This is a slightly unusual one in that the tree was felled on the client’s property and for sentimental reasons he had it milled on site in order to make something out of.

That could be an interesting project, and with those big knots, some loose, they might be the cause of distortion in any worked boards. So your idea of keeping it all a bit rusticated and chunky is probably the right design approach because it allows for future 'character' developments, i.e., voids where knots may fall out and localised distortion emanating from distorted grain surrounding the knots. I don't think I've ever come across boards of monkey puzzle tree, but I know it's in the same genus as parana pine and hoop pine, neither of which, like monkey puzzle, are actually pine.

If you are sure, or even if you're not sure, there is existing common furniture beetle infestation in those boards, and you wish to try and confer some protection during seasoning you might consider a generous application or two of something like this prior to stickering the wood up to season: it would be in place to kill any emerging adult beetles and almost certainly have some deterrent effect on adult beetles laying eggs. It looks like the wood has already been stickered for seasoning based on your images, and is either partly seasoned or already as dry as it's likely to get with air drying here in the UK, i.e., ~18 - 20% MC. If it's been drying in a well ventilated shed it may be a little drier at perhaps 15 - 16% MC, which is still a bit on the wet side for indoor furniture, so final conditioning to bring the wood down to ~10 - 12% MC prior to making the furniture would be a good idea. Still, there'd be no harm that I can see in taking an existing partially seasoned stack apart, slathering on bug killer, allowing a bit of time for surface moisture caused by the application of the bug killer to dissipate, and re-stickering the pile to complete the seasoning. Slainte.