Powder post beetles in Oak

[adowden]

This weekend we were jointing and planing some red and white oak that was from our air dried lumber. We had brought it up the to attic of my workshop about one year ago. I thought the heat in the attic would help deter any powder post beetles. I know this summer the temperature during the day was well above 100 degrees. The wood is good and dry as it has been drying for about five years. When we were pulling the boards out to plane, there was some evidence of powder post beetle (lyctid) activity. A couple of 10' long oak boards had no more than two small piles of dust under them. The other four boards we pulled had no active dust piles.

I have several questions about this after reading about them on the internet:

1) If the eggs are laid on the surface and the visible holes are the exit holes, can you assume that you have removed the eggs if you plane 1/8" off both sides and cut out any exit holes where eggs could be laid?

2) Since the most active time for the beetle activity has passed June-August, is there major urgency to remove the contaminated boards?

3) Based on this experience, I want to build a solar kiln. My only purpose would be sterilizing the air dried wood which should be no higher than 11% MC. I would only need to do very small batches no longer than 8'. Are there any recommendations for good solar kilns for this purpose?

Any other tips and suggestions that you have would be so helpful. We have stacks and stacks of red and white oak, poplar, maple, cedar, and pine that I just don't feel comfortable using on indoor projects until I can heat treat it. The borax chemical treatments sound so expensive.

Thanks,
Amy

 

[skysharks]

Man that sucks for that to happen. Those pesky beetles.
I had a similiar experience a week ago. I got the lumber from a man down the street that had a huge quanity of lumber that he had milled, and now has it stacked up under an roofed structure.
There were so many powder post beetle exit holes, the board looked as to been shot about 20 times with number 8's.
I took it back to the guy, as I couldn't take the chance of exposing my stock to contamination (not knowing).
So I am also interested to see what response you get on this topic

 

[JackLeg]

This weekend we were jointing and planing some red and white oak that was from our air dried lumber. We had brought it up the to attic of my workshop about one year ago. I thought the heat in the attic would help deter any powder post beetles. I know this summer the temperature during the day was well above 100 degrees. The wood is good and dry as it has been drying for about five years. When we were pulling the boards out to plane, there was some evidence of powder post beetle (lyctid) activity. A couple of 10' long oak boards had no more than two small piles of dust under them. The other four boards we pulled had no active dust piles.

I have several questions about this after reading about them on the internet:

1) If the eggs are laid on the surface and the visible holes are the exit holes, can you assume that you have removed the eggs if you plane 1/8" off both sides and cut out any exit holes where eggs could be laid?

2) Since the most active time for the beetle activity has passed June-August, is there major urgency to remove the contaminated boards?

3) Based on this experience, I want to build a solar kiln. My only purpose would be sterilizing the air dried wood which should be no higher than 11% MC. I would only need to do very small batches no longer than 8'. Are there any recommendations for good solar kilns for this purpose?

Any other tips and suggestions that you have would be so helpful. We have stacks and stacks of red and white oak, poplar, maple, cedar, and pine that I just don't feel comfortable using on indoor projects until I can heat treat it. The borax chemical treatments sound so expensive.

Thanks,
Amy

Amy: A solar kiln may not reach the temps you need to sterilize, at least not consistently. Mine only reaches 130F on very sunny and hot days.

You should visit Forestry Forum where you'll find lots of info on all types of solar kilns, from small to large.

Scott Smith is the "resident expert" on "killing out."

Good luck whatever way you go. I've got several thousand feet of oak to dry, so I'll also be interested in how you handle this.

Keep us posted.

:wsmile:

 

[Travis Porter]

I remember some posts about similar questions.

http://www.ncwoodworker.net/forums/showthread.php?p=116799#poststop

But a post from Kyle seems to tell the full story.

Re: Wood Haul....or not

--------------------------------------------------------------------------------

Its probably powder post beetles aka as the lyctid beetle which can survive down to 8% moisture. Heat is the only thing that can effectively kill powderpost and it has to be over 130 F for 24 hours (including the core) to kill the beetle and its larvae which can hatch up to 2 years later. This is primary reason for kiln drying wood.

 

[scsmith42]

Kyle's post hit the nail on the head. 130F in the core is the MINIMUM temperature to maintain for 24 hours, personally I prefer 135. Typically it takes 6 - 12 hours to raise the core temp to 135 at the end of the kiln cycle, so sterilization usually requires 1.5 - 2 days in my kiln.

Reggie, have you thought about augmenting your heat in your solar kiln strickly for sterilization purposes? Seems to me that it shouldn't be too difficult to come up with something.

Scott

 

[JackLeg]

Kyle's post hit the nail on the head. 130F in the core is the MINIMUM temperature to maintain for 24 hours, personally I prefer 135. Typically it takes 6 - 12 hours to raise the core temp to 135 at the end of the kiln cycle, so sterilization usually requires 1.5 - 2 days in my kiln.

Reggie, have you thought about augmenting your heat in your solar kiln strickly for sterilization purposes? Seems to me that it shouldn't be too difficult to come up with something.

Scott

So far we have only been drying cypress and haven't had a problem. When I move to oak, I may need to do just that. Any suggestions? :icon_scra

 

[scsmith42]

Reggie, thinking in terms of "poor-boying" it, if it were me I would look to see where I could place some recirculating fans (you don't want to vent outside while sterilizing), with some heating elements either in front of or behind then. You will need a fan capable of sustained operation in a high temp environment - perhaps an attic fan with a heating coil on the exhaust side? If you've already got recirculating fans, then all you would need to do is add the heat coils, thermostat, contactor (and potentially a rheostat to control current)

You can often obtain spare 5KW heat strips (for heat pumps) from HVAC contractors. Usually a heat pump will ship with a 5kw coil, and oftentimes they have to replace it with a larger one - leaving some new old stock that often gets pitched. I added both 5KW and 10KW coils to my kiln for setting the pitch on pine in the winter (have to heat to 160F), and I think that I have less than $200.00 in the parts.

The key will be balancing the current on the heat coil with the air flow across it, so you don't burn it out. An old electric clothes dryer fan and heat coil may be an alternative - install it outside and duct inlet and exhaust inside the kiln - still a contained environment.

Scott

 

[jeff...]

Reggie, thinking in terms of "poor-boying" it, if it were me I would look to see where I could place some recirculating fans (you don't want to vent outside while sterilizing), with some heating elements either in front of or behind then. You will need a fan capable of sustained operation in a high temp environment - perhaps an attic fan with a heating coil on the exhaust side? If you've already got recirculating fans, then all you would need to do is add the heat coils, thermostat, contactor (and potentially a rheostat to control current)

You can often obtain spare 5KW heat strips (for heat pumps) from HVAC contractors. Usually a heat pump will ship with a 5kw coil, and oftentimes they have to replace it with a larger one - leaving some new old stock that often gets pitched. I added both 5KW and 10KW coils to my kiln for setting the pitch on pine in the winter (have to heat to 160F), and I think that I have less than $200.00 in the parts.

The key will be balancing the current on the heat coil with the air flow across it, so you don't burn it out. An old electric clothes dryer fan and heat coil may be an alternative - install it outside and duct inlet and exhaust inside the kiln - still a contained environment.

Scott

I guess another benefit would be chamber pre heat - I'm really kind of fascinated by it all - I mean how you can take a load from green to 6~10 in a few weeks. One of these days I would like to pick your brain on some of the finer points to me.

 

[cpowell]

I find this topic to be interesting and there are a lot of opinions about how much to worry about those pesky beetles.

I worked with an insect expert (entomologist?) a few years ago on a project in the leaf processing industry - not WW related. He told me that claims of powder post beetle damage in fine furniture is generally exaggerated and said if I just seal the wood with a film finish the beetles will die. He also believed that the few holes that could ensue just add character to the wood and don't risk structural integrity.

I believed him but did NOT have the guts to use any AD stock with PP beetle intrusion in interior furniture projects. I have used it for shop stuff.

The insect guy claimed that PP beetle infestation occurs because the tree is left on the ground for too long after felling. I guess good forestry practices that prevent infestation is more effective than reactive management.


Chuck