I've been kindly offered a microwave oven for seasoning my green turning
timber! I'd be interested to hear your views on the subject of seasoning by
microwave. My old college tutor reckoned it was a "dangerous practice" but
on the other hand I've attended a green woodworking course where the tutor
seasoned greenwood dowels quite successfully in a microwave. Is it best to
microwave original turning blanks or to rough turn and then microwave - or
both? What are your recommendations for safely avoiding boiling the moisture
inside the wood and exploding it? Is it something which will be useful
enough to warrant taking up space in my tiny workshop?

Many thanks

Ron Headon
Swindon, England

I'm off of microwave drying of late. Too many negatives for the single
positive - instant gratification.

Microwaves can make resinous messes out of conifer stock, steam and change
the surface characteristics of my favorite wood - cherry, and must be
monitored carefully lest you light off the piece on an unseen knot or dense
area.

That said, the two schools are high power, short duration and low power (yes
I know it's interrupted full power) greater duration. I favor the latter,
because the inner portions of the wood are insulated by the outer, and will
gain and retain heat better. I want the wood to experience as even heating
as is possible to avoid case-hardening and degrade of the surface. I like
to "tent" the piece in plastic to help it steam and equalize, even though I
know it's the source of some of the color degrade. Try it to see if it's
acceptable to you.

I find the procedure best for pieces which would normally be warp and go,
which means I'm only saving a week's time between cut and finish, though
some will leave pieces thicker to be re-turned. If you do that, leave them
at two or so times the final thickness, take advantage (with gloves!) of the
plastic condition of the wood to ensure it doesn't get too far out of round,
and guard against surface hardening.

I'd take that microwave and use it to heat the water for my tea.

Oh yes, the old bodgers used to dry those chair rungs in hot sand.

"Ron Headon" wrote in message
...
I've been kindly offered a microwave oven for seasoning my green turning
timber! I'd be interested to hear your views on the subject of seasoning
by
microwave. My old college tutor reckoned it was a "dangerous practice" but
on the other hand I've attended a green woodworking course where the tutor
seasoned greenwood dowels quite successfully in a microwave. Is it best to
microwave original turning blanks or to rough turn and then microwave - or
both? What are your recommendations for safely avoiding boiling the
moisture
inside the wood and exploding it? Is it something which will be useful
enough to warrant taking up space in my tiny workshop?

A microwave would be a welcomed addition I believe. I have one in each of
my shops and use it for all kinds of things (not directly related to warming
food or drink). You do need to be careful as you can damage things if not
used properly though. I flamed a goblet a few weeks ago for instance but
then I was intentionally trying to test a few things with that one.

I often quickly dry veneer and thin box (the square kind) stock in the
microwave. I also use it to kill bugs, prepare finishes and lots of other
things. Unless your turning blanks are thin or quite small, it won't do you
much good to microwave them before turning. Rough turn or just turn to
final thickness and then microwave. I recommend the long duration (around 2
minutes) and low cycle power (power #1 or defrost) procedure. Try it and
see if the wood is warm to mildly hot adjust your procedure for your
microwave to get this. Let sit until cool. Repeat until the wood is no
longer cool to the touch (when cooled down) and/or it stops losing weight
between cycles. It may take several cycles to get it to where you want.
Just don't rush things. It's not like defrosting porkchops. g

- Andrew


I've been kindly offered a microwave oven for seasoning my green turning
timber! I'd be interested to hear your views on the subject of seasoning
by
microwave. My old college tutor reckoned it was a "dangerous practice" but
on the other hand I've attended a green woodworking course where the tutor
seasoned greenwood dowels quite successfully in a microwave. Is it best to
microwave original turning blanks or to rough turn and then microwave - or
both? What are your recommendations for safely avoiding boiling the
moisture
inside the wood and exploding it? Is it something which will be useful
enough to warrant taking up space in my tiny workshop?

Many thanks

Ron Headon
Swindon, England

I use a microwave sometimes, but I do not try to get my bowl bone dry with it.
I go through 2 or 3 defrost cycles, depending on the size of the bowl and the
type of wood, setting it aside after each cycle to cool. After the last cycle,
I coat the end grains of the bowl in Anchorseal, and the bowl drys much quicker
than if I had not microwaved it.
Glenn Hodges
Nashville, Ga

Thanks George. A good lesson on microwaving. Info not found in the
usual turning sources. So the peripheral insulation is why my nuked
taters 'n onions are too hot to eat in the middle when just right on the
outside. Just opposite to oven baked. I guess it's the same difference
as hair dryer heating vs nuking green turnings. BTW, would sealing the
end grain of green logs make nuking tend to force moisture out radially
instead of axially. If so, would dewatering be more balanced with less
tendency to crack, or have I discovered a WMD? As usual I'm thinking
(?) outside the cranium. Arch

Fortiter,

You'd melt the sealer, I'll wager. Might even ignite it, which is something
you do _not_ want to do, unless you need a new microwave anyway.

DAMHIKT

Sorry, no free lunch in an uncaring universe....

"Arch" wrote in message
...

BTW, would sealing the
end grain of green logs make nuking tend to force moisture out radially
instead of axially. If so, would dewatering be more balanced with less
tendency to crack, or have I discovered a WMD? As usual I'm thinking
(?) outside the cranium. Arch

There appears to be one benefit to microwaving that most do not mention. If
you get the sample hot enough it softens the lignin (the glue that binds the
fibers together) and some of the stress in the wood is relieved. I have
pretty good luck with woods that crack easily during air drying, if I rough
turn and then microwave. I'm I believer in heating it up on high. I heat it
until it gets hot. and then let it cool to room temp between cycles. Maybe
I can use the full power cooking due to the fact that my shop microwaves are
relatively low power units. (say old). The new one in the kitchen takes 2/3
as long to get stuff hot. I cook things in the microwave until the rate of
weight loss lessens. Usually I get stuff to the point where they pick up a
little weight by the next day. So I guess I get them below the equilibrium
moisture content but not on fire.
The microwave is like all tools. Sometimes they work real well and then
sometimes not. With a lot of use and practice you won't make as many
mistakes with it.

Greg in Oshkosh


"Ron Headon" wrote in message
...
I've been kindly offered a microwave oven for seasoning my green turning
timber! I'd be interested to hear your views on the subject of seasoning
by
microwave. My old college tutor reckoned it was a "dangerous practice" but
on the other hand I've attended a green woodworking course where the tutor
seasoned greenwood dowels quite successfully in a microwave. Is it best to
microwave original turning blanks or to rough turn and then microwave - or
both? What are your recommendations for safely avoiding boiling the
moisture
inside the wood and exploding it? Is it something which will be useful
enough to warrant taking up space in my tiny workshop?

Many thanks

Ron Headon
Swindon, England

One good thing about senility is that you aren't embarrassed to wear out
of style clothes or to ask silly questions. So I ask.
Is it possible that if low power is on and off bursts of full power
(lower duty) maybe low power is actually more efficient than high in
getting water out of green wood because of a pounding or shakng effect.
Somewhat like shakng fruit from a tree. Pounding with a hammer seems to
drive a nail better than steady pressure on the nail head. OK, I'll go
quietly, but I'm gonna get a free lunch some day. Arch

Fortiter,

Is it possible that if low power is on and off bursts of full power
(lower duty) maybe low power is actually more efficient than high in
getting water out of green wood because of a pounding or shakng effect.
Somewhat like shakng fruit from a

In the interests of keeping the price low, its much easier to regulate power in
a microwave by simple on/off pulsing. The net effect is the same, much like DC
pulse width modulated motor controls. The magnetron that creates the microwave
energy wouldn't like low voltage DC anyway.

Thermally, duty cycle modulation is a good way to control the heat. If you were
working with very low mass targets, it would be a problem, but wood bowls have
a fairly high thermal mass.

Don't worry about it! :)

Earle Rich
Mont Vernon, NH

Some people have more time than sense.

http://margo.student.utwente.nl/el/microwave/