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View Ocelot's profile

Sterilizing wood in home oven

by Ocelot
posted 08-08-2017 01:17 AM


27 replies so far

View Loren's profile

Loren

10477 posts in 4182 days


#1 posted 08-08-2017 01:31 AM

“It has been demonstrated (Houseman 2007) that all developmental stages of wood boring beetles are killed if a temperature of at least 120°F is maintained for over 30 minutes.”

source: https://www.thermapure.com/pest-services/wood-boring-beetles/

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bondogaposis

5553 posts in 2885 days


#2 posted 08-08-2017 02:11 AM

All life ceases when internal cell temperature reaches 140°F, with only very few exceptions, like microbes that live in hot springs.

-- Bondo Gaposis

View bbasiaga's profile

bbasiaga

1243 posts in 2529 days


#3 posted 08-08-2017 02:21 AM

160 for about 1min, arguable 30s gets most non-thermophyllic microbes. 140 is the top end of the prime growth range (40-140) for microbes. So I would go hotter. Bugs (complex organisms) are probably done well below that because the proteins that drive their cells will denature and stop working. Loren’s reference is probably a good go by.

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

View Ocelot's profile

Ocelot

2365 posts in 3172 days


#4 posted 08-08-2017 02:42 AM

Thanks!

View sawdustdad's profile

sawdustdad

379 posts in 1419 days


#5 posted 08-08-2017 02:44 AM

Low and slow heat for the most tender meat. Are you using a dry rub?

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

View Mark Wilson's profile

Mark Wilson

2650 posts in 1597 days


#6 posted 08-08-2017 02:51 AM

Don’t most people dry wood in the microwave? If that’s the case, death should be instant and painless, I should think.

-- Mark

View Andre's profile

Andre

2824 posts in 2340 days


#7 posted 08-08-2017 02:54 AM

Probably don’t have to say it, but that should be the internal temp. Wood is a very good insulator so depending on the thickness?

-- Lifting one end of the plank.

View Ocelot's profile

Ocelot

2365 posts in 3172 days


#8 posted 08-08-2017 03:32 AM

Yes. I don’t want to drill hole for thermometer, so maybe I’ll leave it overnight. The pieces are about 1.5 inch square and 11 inches long.

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Ocelot

2365 posts in 3172 days


#9 posted 08-08-2017 03:37 AM



Is 150 too much?

- Ocelot


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Redoak49

4229 posts in 2523 days


#10 posted 08-08-2017 11:09 AM

If I put wood in my wife’s oven, the bugs would not be the only thing hurting.

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Ocelot

2365 posts in 3172 days


#11 posted 08-08-2017 11:33 AM

I have an excellent wife!
Of course, I could claim that it’s my oven, because I had it before we married… But then again I did stand in church and, among other things, declared “with all my earthly possessions,I thee endow.” anyway… She said it’s ok… Even if it has bugs in it.

View eviglotti's profile

eviglotti

5 posts in 505 days


#12 posted 06-25-2018 06:06 AM

Hello,

I’m new to this forum, but found this discussion to be exactly the line of questions I have…Rather than use a home oven, I figured I would use my outdoor BBQ grill since I have 5 burners, so I can turn 3 on and 2 off to use indirect heat to get a temp that is 350 and below so for small items I could create whatever temperature I want without direct flame on wood.

Has anyone found any rough rule of thumb for what temp and for how long based on xyz thickness? Or is the best way to drill a tiny hole and put a meat thermometer in there to to judge if it has maintained 140 for over 30 min?

Thanks!

View John Smith's profile

John Smith

2044 posts in 697 days


#13 posted 06-25-2018 11:39 AM

.

-- I am a painter. That's what I do. I paint things --

View Lazyman's profile

Lazyman

4080 posts in 1922 days


#14 posted 06-25-2018 12:03 PM



Hello,

I m new to this forum, but found this discussion to be exactly the line of questions I have…Rather than use a home oven, I figured I would use my outdoor BBQ grill since I have 5 burners, so I can turn 3 on and 2 off to use indirect heat to get a temp that is 350 and below so for small items I could create whatever temperature I want without direct flame on wood.

Has anyone found any rough rule of thumb for what temp and for how long based on xyz thickness? Or is the best way to drill a tiny hole and put a meat thermometer in there to to judge if it has maintained 140 for over 30 min?

Thanks!

- eviglotti


I bought a cheap microwave for my shop at a garage sale that I use for drying turning blanks. If your goal is to kill bugs, depending upon how big your chunk of wood is, 30-60 seconds at 50% power should kill them.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View eviglotti's profile

eviglotti

5 posts in 505 days


#15 posted 06-25-2018 02:03 PM

Interesting, I have seen the microwave option mentioned by many. Has anyone actually tested this with wood where they knew there was live bugs in it and then afterwards you could see they were dead? I am also sometimes cutting my own veneers that are a bit thicker than normal at about 1.5mm. I’d imagine this wouldn’t take that long in the microwave, especially since even with 30 seconds I would bet they would warp and may get damaged?

View Lazyman's profile

Lazyman

4080 posts in 1922 days


#16 posted 06-25-2018 02:29 PM

I’ve never use the microwave specifically to kill the bugs but I have found dead ones afterwards. They usually look like they sort of exploded. The microwave will heat the moisture in any bugs and kill them pretty quickly but I don’t think that you need to worry about killing bugs in veneer. The saw blade will take care of killing almost any bug in something as thin as 1.5mm. If you do put veneer in the microwave, you’ll need to adjust the time depending upon how much wood you put in there at a time. You can shorten the time or lower the power setting to prevent burning the wood. It will also depend upon how dry the wood is when you microwave it. If the wood is relatively dry, it won’t warp much but might burn. Even wet, you can burn it if you heat it too long or at too high a power setting. When I have done this by mistake, the burning usually occurs deep inside, not on the surface. After heating, the wood should be cool enough to handle with bare hands.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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eviglotti

5 posts in 505 days


#17 posted 06-25-2018 04:39 PM

Agreed, I was thinking much the same with veneer. I’ve just heard arguments of “there are bugs you can’t even see” which seems slightly meticulous, but maybe it’s warranted. I have also heard the camp that a microwave wouldn’t do enough and it needs prolonged heat like here: https://woodbarter.com/threads/killing-bugs-in-your-wood.9390/

Thanks for the info.

View EarlS's profile

EarlS

3162 posts in 2882 days


#18 posted 06-25-2018 05:00 PM

I’d think the problem with a microwave is that it heats up water (or moisture in the wood) to boiling which means that the wood moisture will turn to steam and start doing odd things to the wood as it tries to get out. In an over, the moisture gets hot but not hot enough that it is boiling (212 deg F) and turning to steam.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

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MrUnix

7499 posts in 2733 days


#19 posted 06-25-2018 06:52 PM

Problem with microwave is it won’t penetrate very far into the wood – so it’s fine with smaller (thinner) material, but not so good for large pieces. But it will heat it up. Standard heat treatment is to get the wood to 56ᵒC (~133ᵒF) for 30 minutes. There was a good article about this in the European Journal of Wood and Wood Products that might be a good read if interested:

Comparative study of radio-frequency and microwave heating for phytosanitary treatment of wood

For a conventional oven… 150ᵒF for long enough to get the internal temperature over the threshold for 30 minutes should work just fine. Overnight might be a bit of an overkill, but probably wont hurt anything either.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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jerkylips

495 posts in 3105 days


#20 posted 06-25-2018 08:50 PM

not sure how “standard” this is, but my oven only goes down to 170 degrees. There’s no way I could maintain the temp below that point.

If the only goal is to kill bugs, couldn’t you seal it up in plastic/tarp/etc, & fumigate it?

View Andybb's profile

Andybb

2146 posts in 1138 days


#21 posted 06-25-2018 09:38 PM

I would think that 30-60 seconds in a microwave would even kill Alien. The oven might dry them out and make them crispy if you’re using compressed air to clean them out but nothing can survive a microwave.

-- Andy - Seattle USA

View Lazyman's profile

Lazyman

4080 posts in 1922 days


#22 posted 06-25-2018 10:37 PM

The article that Brad cited was for relatively large pieces, about 4 ” to 10” cubes, and doesn’t compare results to conventional ovens (much less consumer microwave ovens). All I know is that when I forgot to reduce the power setting to 50% for a bowl blank that was rough turned to about 1” thick, I discovered after turning the bowl that the center was charred after about 2 minutes at max power. So I would think that if the blank is smaller than 2-3” in any dimension, it should work just fine in the microwave.

But if you are sawing veneer, and unless you are trying to prevent damage for later use, let the saw kill the varmints for you.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View eviglotti's profile

eviglotti

5 posts in 505 days


#23 posted 07-06-2018 06:05 AM

Hello all,

So I finally gave this a try. With a 5 burner grill, I can turn on the outside burners and get anywhere from 150 to 350 degrees without direct flame under the wood. So I tried first with 150 degrees with both outside burners on low. After about 4 hours, I drilled a tiny hole in some of the 1/2” wood I have in there and my meat thermometer registered still only about 100 degrees F. I finally gave up and turned up the heat so it was about 220 degrees in the grill, but still after about 3 hours more of that, I only got up to 120 degrees inside the wood which is still well short of the sustained 140 I need. I’d really rather not leave my BBQ unattended for 24 hours, but is that reasonably what it will take? Or can I pump it up to 350 for grill temp and speed this up a bit if the wood is already dry or will this split it, catch it on fire or something else not so good???

Any real world experience and proper expectations is certainly appreciated :)

Thanks!

View William Shelley's profile

William Shelley

609 posts in 2004 days


#24 posted 07-06-2018 03:47 PM

You guys are making this way too difficult. Get a cheap single pane window from a building recycling center, make a box out of plywood and paint the inside black. The window is the top/lid for the box. Put your wood inside and put the whole thing out in the sun for a day. Think about how hot the inside of a car gets… your box will be even hotter than that. Rudimentary solar kiln.

-- Woodworking from an engineer's perspective

View eviglotti's profile

eviglotti

5 posts in 505 days


#25 posted 07-07-2018 11:23 PM

Hello William,

I love this idea as a solar kiln would be cheap and easy. It just so happens we had a heat wave here in San Diego yesterday and today, and the outdoor temperatures hit 100 degrees and full sun. So I built the little guy below for some small pieces. It’s plywood with glue sealed edges, painted black, with a piece of clear acrylic just to keep things simple. I put some flex seal around the edges and tape to keep it relatively sealed. Again, just keeping things super simple.

Anyway, after an entire day out there, these tiny little pieces hit only about 110 to 120 at the max in the core, and considering it was 100 degrees outside, that isn’t a huge difference and doesn’t seem hot enough to kill any bugs since it seems like we need 130 or 140 sustained for at least 30 minutes.

Is this worth the effort or just go a different direction?

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eflanders

326 posts in 2385 days


#26 posted 07-08-2018 12:48 AM

I find this topic very interesting and had heard from the FDA that 200’ f for 1 hr. per inch of thickness is what is required by the Fed’s for interstate and intercontinental transport. Wood pallets from non u.s. countries are supposed to be “heat treated” to prevent foreign bugs from being transported here. Because of this, I heat treat any wood based food utensils I make per the previously mentioned “recipe”.

View Lazyman's profile

Lazyman

4080 posts in 1922 days


#27 posted 07-08-2018 02:59 PM

I have just used clear thick plastic drop clothes for a quick and dirty kiln to kill ambrosia beetles. I just wrapped the wood in the plastic and left it sitting on my concrete driveway which only gets shade at dusk and dawn. The concrete itself probably hits 120+ degrees on a typical summer day. I stuck a wireless thermometer and humidity sensor inside the plastic to get an idea how it was doing. I don’t remember exactly how hot it got but I think that the temp got to over 150 (probably the max of the sensor?) and the humidity stayed over 80% since I was trying to get it hot, not necessarily dry. I opened it up at night to let some of the moisture out.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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