Drying Wood for Turning Using Microwave?
JCP
I have always used commercial wood, which has been dryed. But, I see
pieces that have potential (most of my turning is pens) - green pieces
that is.
I have heard that wood can be quick dried using the microwave set on
defrost.
Anyone have experience doing this?
Jay Planalp
Terry A. Austin
Jay,
I have been turning for quite a while. I am a Native American
flutemaker who picked up turning pens to pass out to my friends a couple
of years ago. I have microwave dried quite a few pieces with good
overall luck. I have done pen blanks as well as other pieces this way.
The keys to success are...
Cut blanks to a workable size before drying, I cut pen blanks roughly to
1/2" x 1/2" x 3" depending on which pen or small project I am working
on.
Microwave on defrost only and work in small time increments.
Occasionally I will switch my microwave to full power for the _very
first_ burst then switch to 30 second to 1 minute bursts on defrost. I
usually will allow 5-10 minutes between these heatings to prevent the
wood from becoming too hot. Keep close watch, smell and feel to prevent
burning. If you see darkening (burning) smell smoke or pick up a piece
that is uncomfortably warm then allow it to cool. The wood will get
warm but you should be able to hold it in your hand without being
uncomfortable.
What you are trying to do is to drive out a large portion of the
moisture - as if that were not obvious, so you will most likely see some
steam when opening the door and may see foaming especially at the
endgrain.
I am single and live alone but have heard from some woodworkers who
irritated spouses by this practice. Some woods can smell strongly when
mirowaved especially if burned.
Be aware that different models of microwaves have different levels of
power, err on the side of caution - shorter times and lowest powers
until you know how your microwave will perform.
Resinous woods can be dangerous ESPECIALLY if they contain pockets of
pitch that might vaporize violently when heated to boiling.
Also you can expect some checking/cracking I usually cut more pen blanks
than I will use and will often cut them 1/2" long to allow cutoff space
to stop a split. If you dry several blanks you are pretty likely to get
mostly decent blanks.
I will often dry pen blanks in the evening while sitting down to dinner
and a bit of TV allowing the wood to cool to a slight warmth when held
in the hand before re-nuking. Even better results can be had if you
repeat this several nights in a row with the same pieces.
Patience, short nuking times with pauses to cool are critical. I also
allow pieces to set for at least a few hours and if possible several
days before drilling and turning.
I have some beautiful mesquite root pieces that I harvested in early
November. I have worked several of these pieces after microwaving, one
is nuking as I type this. While a few of these had some splitting occur
there has been no major loss. Pieces that made it to the lathe have had
absolutely no post-turning splitting or cracking.
Good luck. This drying method can work but you MUST be careful. If you
share your residence and kitchen I STRONGLY suggest you discuss this
with your spouse/room mates BEFORE you dry wood this way. Even better
if you also have them check it after your first session to be sure they
know what they agreed to.
Final pointer - as a practiced woodworker I know no one would miss
finding a nail in a piece of wood they were working with but... BY ALL
MEANS __N E V E R__ microwave a piece of wood with a nail, staple, screw
or any other piece of metal in it.
Good luck
Terry Austin
ALYSONSDAD
I have dried several green bowls. There has been several discussions on
the rec. woodworking. You might try dejanews. The consensus (sp) was
never go higher with the power than defrost. One guy did several thousand
dollars when the bowl caught fire. The longest time I have ever used is
eight minutes, wait 15, the eight more. I stop at around 30 total cooking
time.
Bill Wiggins
Irondale, AL
ALYSONSDAD
ALYSONSDAD
ALYSONSDAD
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Will Simpson
- Thank you Terry for your description of your microwave drying process.
- I also use the very same process as Terry for some of my pens. Although I use 15-25 sec on defrost per blast. Wait 5 mins. repeat several times every night for 3-4 days.
- The last group I did I underestimated the moisture content of some eyed mesquite burl and had already cut, drilled, glued in the brass tubes and rough turned the pen halves leaving the wood 3/16 inch thick before drying.
- You might think I had violated the 11th commandment "Thou shalt not place anything metal into the microwave" but after placing a thin insulator (lid to large plastic containor) between the pens and the metal revolving tray in the microwave I experineced no problems. In fact I can't help but think the peice dried more completely, quicker and with less checking because the potential stresses within the wood were less to start with.
- On word of caution. I did try to dry these pen parts by placing them directly on the metal tray within my microwave and within a few seconds there was tremendous smoking, sparking, and crackling of the energy arcing throught the wood between the metal tray and the brass tube. The insulator between the pen parts and the microwave solved that.
- Caution ** Your mileage may vary. Always check with "Ruler of the Domain" before embarking on any adventure in the kitchen. And keep your finger on the stop button watching for smoke, sparks, unusual oders. Go slow.
- Will Simpson
- Kestrel Wood Turning Studio
- Troy, Idaho
ALYSONSDAD
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Steve Worcester
Wood for pens, I would just wax the ends and let sit. To microwave
wood, it needs to be turned down to about 1" (25mm) and put on defrost
with about 1min on, 2-3 minutes off cycle. This allows moisture
evaporation without too much heat builup (a major microwave crack
maker). It takes experimentation, and a love of unintentional warpage.
Also kinda fun to do split vessel work, and let it warp away!
Steve
On Mon, 13 Jan 1997 18:32:39 -0500, JCP <car...@erols.com> wrote:
>I have always used commercial wood, which has been dryed. But, I see
>pieces that have potential (most of my turning is pens) - green pieces
>that is.
>
>I have heard that wood can be quick dried using the microwave set on
>defrost.
>
>Anyone have experience doing this?
>
>Jay Planalp
Steve Worcester
Madera Creations, Plano, TX
Pens are made by fools like me but only God can make a tree
ALYSONSDAD
David R. Smith
JCP wrote:
>
> I have always used commercial wood, which has been dryed. But, I see
> pieces that have potential (most of my turning is pens) - green pieces
> that is.
>
> I have heard that wood can be quick dried using the microwave set on
> defrost.
>
> Anyone have experience doing this?
>
> Jay Planalp
Jay, how much of a hurry are you in? If you just cut up your blanks a
little oversize, maybe coat the ends, then store them where there's
halfway decent air circulation, a pen blank size piece of wood just
isn't going to take very long to dry. You'll lose less wood due to
degrade, and gain less ire from OCD's who think microwaves are only
meant to cook food.
Jahn
Terry A. Austin wrote:
> > I will often dry pen blanks in the evening while sitting down to dinner and a bit of TV allowing the wood to cool to a slight warmth when held in the hand before re-nuking.
Good idea but if you're going to devote a whole evening why don't you
just turn your regular oven on "Low" and let blanks sit in there on
their own for the evening. We discovered this after smoking up two
microwaves and finding out that wood really can burn from the inside -
out.
My second point is an idea that can satisfy a couple of people. If you
want to try turning pens from pine or something cheap before investing
in the nicer blanks; hook up with a tole painter. All the decorative
painting magazines advertise blank pens to paint. You might get a tole
painter to pay for the guts and you can practice to your heart's
content. That way your practice pieces will be put to good use and your
painter friend will have perfectly good blanks to decorate. FYI, most
decorative arts pen blanks are fatter than the "Cross-style" pens a lot
of people turn.
Gail
--
"Dreams have as much influence as actions."
>>>Stephane Mallarme
JA...@LLNL.GOV
Douglas Turner
ISteve Worcester wrote:
>
> Wood for pens, I would just wax the ends and let sit. To microwave
> wood, it needs to be turned down to about 1" (25mm) and put on defrost
> with about 1min on, 2-3 minutes off cycle. This allows moisture
> evaporation without too much heat builup (a major microwave crack
> maker). It takes experimentation, and a love of unintentional warpage.
> Also kinda fun to do split vessel work, and let it warp away!
> Steve
>
>
> >I have always used commercial wood, which has been dryed. But, I see
> >pieces that have potential (most of my turning is pens) - green pieces
> >that is.
> >
> >I have heard that wood can be quick dried using the microwave set on
> >defrost.
> >
> >Anyone have experience doing this?
> >
> >Jay Planalp
>
> Madera Creations, Plano, TX
> Pens are made by fools like me but only God can make a tree
for most woods. There are a few woods that have a tendency to crack
badly if treated this way - for example Carolina Cherry and Russian
Olive. For crack prone woods I slice the wood into boards and then into
strips. I freeze the strips for 24 hrs and then thaw in the
refrigerator for about 2 weeks. The strips are usually dry enough to
turn into pens without cracking. I picked up this tip from Vic Wood from
Australia and it works for me.
Doug Turner <tur...@earthlink.net>
jlo...@aol.com
In article <32DDBD...@earthlink.net>, Douglas Turner
<tur...@earthlink.net> writes:
>I freeze the strips for 24 hrs and then thaw in the refrigerator for
about 2 weeks.
I've seen a couple of references to this procedure on this newsgroup and
am curious why it works. Here in northern U.S., trees freeze regularly
every winter without any apparent drying effect. My firewood pile has
been frozen to -20 F, far colder than any household freezer, and the wood
still split and cracked. Can someone explain the physiological
characteristics of timber that makes this technique effective?
- John Lorch -
Berger
In article <19970117142...@ladder01.news.aol.com>,
the moisture to travel out of the wood much faster and most important more
evenly. The use of a refrigerator has a dehumidifying effect in a controled
enviroment.
One thing to remember with wood is that water is stored in two destinct areas,
in the cell and outside the cells. The later dries out first and does not
effect shrinkage at all, it is when the moisture in the cell begins to dry out
that the movement begins. By freezing or boiling the two areas have free
access to the atmosphere and can escape evenly and cause the least damage.
In traditional timber milling the trees were cut in the fall and left to
freeze before milling in the spring.
Cheers Soren
JCP
fro...@mnsi.net, Tom, Hamilton wrote:
> (snip)
>
> 2) This proliferation of discussion re pen turning seems pointless.
> There is nothing difficult about turning a pen blank . Or drying it..
>
> 3)Microwave ovens cook from the inside out.
>
> Take a piece of any kind of green wood. Prepare a Bowl blank Turn it; Dry (treat) it, finish it. More of a challenge than pen making ??????
>
> Cheers: Tom
I agree that pen making isn't that challenging. But to a novice it is
quite reqarding and more experienced turners may just like making pens.
So, what is wrong with discussing it? To people who like pens, there
indeed is a point to discussing it.
Jay
John Jordan
wrbe...@chch.planet.org.nz (Berger) wrote:
>Cheers Soren
Greetings Soren,
I'm with John here as far as freezing goes. I've turned a lot of
frozen wood, and have a LOT of experience with green wood in general,
and I'm unable to ascertain any difference. If it was true that the
cell walls burst, then my trees would no longer contain bound water,
as it has been well below freezing here for days-though apparently
not as cold as where John lives<G>. How would the tree know that it's
been cut?
I don't know about boiling, but it clearly affects the wood enough
to allow steam bending etc.
Gael Montgomery was visiting last summer, and we talked about this a
bit. I would like to see a true, controlled test, with identical
samples of at least three or four different species cut, weighed etc.
and several different methods applied. Anyone have other methods to
add? Some sort of microscopic examination perhaps.
Sounds like a good subject for a magazine article.
BTW I would agree that the freezer is a way to moderate drying, and it
certainly prevents fungal growth and bugs.
I hope all's well with you.
Respectfully (and sceptically <g>)
John Jordan
Douglas Turner
This is the explanation that Vic Wood gave also. I believe the
thickness of the strips versus the fire wood pile has a lot to do with
controlling cracking. I have used this with Russian olive which
contains a lot of oil/wax and is very difficult to dry without cracking
especially the root burls where some of the prettiest grains are.
Carolina Cherry is also difficult to dry because of the grain swirls and
reaction wood but this responds well to freezing.
Doug Turner
Sergio Caballero
On Mon, 13 Jan 1997 18:32:39 -0500, JCP <car...@erols.com> wrote:
>I have always used commercial wood, which has been dryed. But, I see
>pieces that have potential (most of my turning is pens) - green pieces
>that is.
>
>I have heard that wood can be quick dried using the microwave set on
>defrost.
>
>Anyone have experience doing this?
>
>Jay Planalp
Following is the text of a message I posted to rec.woodworking
regarding a similar question last month:
The process is really pretty easy. I turn the piece to about 10% more
than I want as final wall thickness. I then put the piece on a bed of
newspaper (to help absorb moisture) in the microwave and "cook" it on
DEFROST cycle for 5-10 minutes, depending on the size of the piece. I
then let it cool for another 5-10 min, and repeat the heating cycle.
I keep alternating these heating and cooling cycles until the piece no
longer loses weight, or until it "feels" dry (this is something that
comes with practice). This usually takes about 10 heating/cooling
cycles for a bowl about 8" diameter with a 1/8" wall thickness. Of
course you'll have to experiment since different woods lose their
moisture at different rates and different microwave ovens have vastly
different power outputs. It's also a good idea to occasionally turn or
move the piece around inside the oven since all microwave ovens have
"hot spots" that get more radiation than other areas in the chamber.
The most important thing about microwaving turnings is to not overcook
them, as this will almost certainly cause them to check or crack.
Remember that uneven moisture loss (more rapid loss from one area,
slower loss from a nearby area) is what causes wood to check and
crack. If immediately after a heat cycle the piece is too hot to hold
you need to either reduce the cook power or shorten the heating time.
With this process you get much less warping of the piece than you do
with air drying over several months. That's why I turn to only 10% or
so more than final thickness before microwave drying.
Hope this helps.
Sergio Caballero
Caballero Woodwork
Gainesville (Home of the 1996 NCAA Footbal Champion Gators)
Florida
Tom Puskar
> Yes, i frequently dry wood in the microwave.
>
Care to share the details and results?
Martin Eastburn
Must have a unit in the shop for such.
Wife would try the new knives out on you if the one in the kitchen was used!
Use defrost. Slow and gentle. Want to wrap it in a cloth - damp to
begin with and let it absorb the water and prevent explosions from
going everywhere. Rare. Sometimes if there is sugar in the sap you
will or can burn it. Smells like burnt sugar. This can color the wood
or out-gassing to much steam might explode a thin wall.
Use low power or pulse with defrost.
Martin
Dr. Deb
> I have always used commercial wood, which has been dryed. But, I see
> pieces that have potential (most of my turning is pens) - green pieces
> that is.
>
> I have heard that wood can be quick dried using the microwave set on
> defrost.
>
> Anyone have experience doing this?
>
> Jay Planalp
As I said, it seems to work well. Just do not get impatient (see above). Keep your times to a couple of minutes on medium and rest twice as long between "nukings" and you should be fine.