bugs & the microwave

[julie Graf]

Hi,

I just microwaved some slabs of fresh cut walnutm for 20 minutes, opened the door, and saw a bug crawling around!!!

zapped it for another 20 minutes - opened the door, peeled off some bark, and saw more bugs!!!!

what is the deal - more time? broken microwave? it got hot in there...
nuke-resistant bugs?

any suggestions?

I have a large amount of wood to nuke - 4 or 5 stumps worth - and don't want to use chemicals. But do foggers penetrate the wood? maybe they are better...

i'd love opinions.

[Jim Becker]

Your gouge will take care of those little buggers no sweat...just wear a raincoat and a full face mask! :D

(I can't answer your question about zapping them...sounds strange to me that they are still crawling after all that time...)

[julie Graf]

yeah, the only problem with that is some of the wood is not for turning! :)

[Curt Fuller]

Wow, 20 minutes! I've nuked a few things to try and speed up the drying and after 2 or 3 minutes they feel like they're about to burst into flames. I used the full power setting and it literally boils the moisture from the wood after about 1 minute. I think you're either using too low of a power setting, have a faulty microwave, or you better get out of the house quick because you've got some kind of super resiliant bugs that are going to be in real foul mood.

[Greg Funk]

The electro-magnetic field within a microwave is not uniform, hence the need for rotary tables. The microwaves bounce around inside the oven reflecting off the walls and create standing waves. Ants and other little bugs can just walk over to the 'cool' spots and they won't get cooked.

Greg

[Jim Johnstun]

ants and other small bugs such as powder post beatles don't have any moisture in their body and are imune to micro waves.

[Richard Madison]

Julie,
Something obviously wrong with the oven and/or procedure. Twenty (20) minutes in even an old 600 watt oven at full power setting will incinerate a lot of things, including wood, which ignites at around 400F and up. Unless you are almost completely filling the oven. And maybe expecting it to dry the full load of wood in one session. Certainly some volumes of the wood will become hot, but not all.

Suggest search of this forum for microwave drying. Usually done for a single piece or several small pieces per batch. Usual procedure is something like nuke on high for two minutes, cool to near room temp., and repeat multiple times. There are variations of course, but this is the general idea.

Might want to try just one or two of your "slabs" at a time this way, with stickers between slabs. Also might want to try removing the wood but leave the bugs in the oven and nuke them for a couple minutes to validate Jim's hypothesis. The bugs must contain some water, but it may be a much smaller percentage than the wet walnut.

For ref., I used to dry wet oak chips in some old 600 watt ovens for later use in a consumer product. A large container of chips required several sessions in an oven, with mixing between sessions to release the water vapor and reestablish uniform temperature within the batch. When a batch was "cooked" a little too long, a small volume of material near the center would be turned to charcoal while the material at the edges was still wet.

Hope this gives some insite to your problem.

[julie Graf]

I do have 3 3 inch thick slabs in there - separated by stickers, but it is a lot. I'll try it with just one and see what happens. (I'm so impatient!)

The wood is very wet, and seems to be drying - it was steaming when I opened the door, but perhaps with that much wood, all of it doesn't get hit.

[Ralph Lindberg]

You want to slowly dry the wood. Not cook it.

I usually microwave a rough turned bowl at full power of 30 seconds, then let it sit (door closed) for 10 minutes.

I repeat this a couple times. Then I start checking the wood, either by weighing it, or with a moisture meter. When it stops changing, I set the bowl aside for a few days to "temper".

[Paul Engle]

Micro waves use their energy to vibrate moisture in something, the movement causes friction and that is heat , bugs with out much or little moisture will not vibrate hence no friction , no heat , no kill. if your oven is not steaming hot after say 1 minute , then either the power setting is defunct or the whole oven is defunct 30 seconds should be enuf to steam a piece of wet wood on full power say at 1000 watts or higher. I dont think i would try to steam dry all that wood, cut into blanks and coat the ends or non bark areas with either anchor seal, parafin wax or a couple coats of latex exterior paint.

[TYLER WOOD]

I picture these bugs, sitting on the wood. Looking through the glass sticking their tongues out at you.:p Nah nah nah nah boo boo.:p Ahhhhhhh steam room, any one have birch branches? Breath my friend, breath!!!!! (Halls commercial)

Reduce the amount of wood you have in there. Go with shorter intervals. 3" thick slabs will take a while to dry. Probably 3-4 times a day, a weeks worth of days. Then let sit for a few days and see what the moisture content is then.

[Jon Lanier]

You may want to look at this: http://aic.stanford.edu/jaic/articles/jaic21-02-001_2.html

I also read from: http://answers.google.com/answers/threadview?id=265489

A microwave oven emits evenly spaced, waves of energy called "standing
waves" that are focused on the plate inside your microwave. Only some
parts of the of the plate are exposed to these waves and that the
inside of the oven is not completely exposed to the waves. This is the
reason why the plate was designed to rotate and expose the food to
these waves. Inside a microwave oven, the air in the oven is at room
temperature. Air doesn't absorb the emitted waves of energy well, so
the air in a microwave oven doesn't get hot. Heat is produced due to
"molecular friction" when the atoms of the food are excited and
"twisted back and forth." Microwave doesn't remain still in
objects and passes through most matter except metal.

Given the size of the fly and the space inside the oven, there is
still plenty of space where it can move safely. Even if it gets hit by
some of the emitted standing waves, its small surface area means very
little energy is absorbed to produce heat. For as long as it keeps on
moving and/or not remain in a place where it will be constantly and
repetitively bombarded by the emitted energy, it will not be "cooked"
inside and it will survive. The situation is similar to moving your
finger through a flame. Keep it moving and very little heat is
absorbed. Hold it in the flame and your finger will get burned.

[Reed Gray]

I have a friend who dries a lot of ponderosa pine burls (actually not burls, but burl like growth caused by bugs). He says that they need 2 sessions in the microwave. Shorter bursts, with pauses inbetween. With Walnut, I have noticed that most of the time, the bugs will get into the sap wood, but not into the heart wood. You might sticker them and cover, and remove the bark and let them dry for a while before you finish them in the microwave.
robo hippy

[Scott Hurley]

When I dry a bowl in the microwave, I set it on defrost, and give it 2 minutes, then let it cool before I repeat the process. This time, I forgot to set it on defrost, and after about 1:45, I started to smell smoke. Luckily, it didn't catch fire, but the shop smelled like smoke for 3 days. Needless to say, I'm more careful now.


http://members.cox.net/scotthurley/images/woodworking_gallery/mistakes/Burned_Bowl.jpg

[Skip Spaulding]

Sounds to me like you have to get the bugs to drink and then not move, maybe a little bourbon!

[Richard Madison]

Julie,
Good. One slab at a time; cook on high for 2 or 3 minutes and remove from oven. Allow to cool to near room temp. (maybe 15-30 minutes) and repeat. The water can only escape from the surface, and it takes time for the moisture in the center to migrate to the outside surface. You are trying to accomplish 3 years of air drying in one swell foop. Take it a little slower.

[Jon Lanier]

I do have a question. I'm pretty sure I know the answer but I want to make sure. I know I keep a microwave near my shop but that's because I heat up water for ferrules for golf clubs when I'm building. (a hot chocolate is nice sometimes too.) But when I told my wife about this thread, she asked, "They don't use the 'kitchen' microwave for drying their wood, do they?"

Well?

[John Schreiber]

"They don't use the 'kitchen' microwave for drying their wood, do they?"

"They" have been known to do it on occasion. The only time it was a problem was when I left some maple in too long and it started to burn. It was like burned popcorn but 10 times worse. I had to take the microwave outside for a day to let it air out.

I used the wood anyway and decided the "charcoal colored" area was a feature not a flaw.

[Richard Madison]

Jon,
If you use a microwave oven INSIDE the house (especially the one in the kitchen) to cook wood, "you might be a redneck". If you are offended by this comment, -----

Seriously, it tends to "stinkify" the oven and surrounding area, especially when you inadvertantly (but inevitably) make some charcoal or even a small campfire. Best to get a cheapie used one to use in the shop or anywhere outside the house. The exterior aroma will dissipate, but I wouldn't want to heat food in the "wood" oven.