[Woodcarver] drying a 10" log

Tue Jun 22 10:32:56 EDT 2004


Thanks Lynn, I hadn't seen that either,  Phill


----- Original Message ----- 
From: "Lynn Diel" <carvers_creek at yahoo.com>
To: "[Woodcarver]" <woodcarver at six.pairlist.net>
Sent: Tuesday, June 22, 2004 6:49 AM
Subject: Re: [Woodcarver] drying a 10" log


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>
> Ray
> To follow up on what Phill wrote, there is an article
> in the woodcarver ezine located at the following url;
> http://carverscompanion.com/Ezine/Vol2Issue4/Vol2Issue4TOC.html
> it talks about how you can build your own vacuum kiln.
> If you have any questions, let me know.
> Good luck Lynn
>
>
> --- Phill Pittman <phill at masterwerkes.com> wrote:
> > To make a DONATION to the Mailing List using PayPal
> > OR regular mail, click this link:
> > http://wwwoodcarver.com/WWWList/WWWList.html
> >
> > Hi Ray.  there is no simple way ( if drying the wood
> > ) to prevent splitting
> > without involving an environment with a partial
> > vacuum in it. We carve large
> > ( and small )green wood regularly and anything you
> > do that accelerates air
> > flow past it will cause cracking where the air
> > crosses the surface. (
> > aromatic cedar and a few imported oil laden woods
> > are some of the only
> > exception ). drilling holes will help if naturally
> > drying, but hurt if you
> > force air with the vacuum.
> >
> >  Making a vacuum chamber for a log is not as
> > difficult as it seems.Large
> > schedule 80 pvc ( the kind you will see around
> > public sewer projects ) will
> > work in a pinch, but if it is something you might
> > want to repeat later, a
> > section of iron pipe that the log will fit inside of
> > will do it. I got mine
> > from a local scrap metal place and had enough left
> > over for the " shop"
> > smoker/bar-b-q). Welding a plate over one end and
> > fashioning a removable
> > plate for the other end will work for the vacuum.
> > remember a vacuum is self
> > sealing and getting an airtight seal is more
> > important than fasteners or
> > bolts etc. It is also much easier to do. If your
> > project allows, remove any
> > surface of the wood that you can before drying, but
> > keep the fresh cuts wet
> > until you are putting it in the tube.
> > The fluids inside the log will gasify at near room
> > temperature in a 25"
> > vacuum. If you are lucky enough to score a good
> > vacuum pump, it will work at
> > room temperature.
> > As I am sure you know, wood splits when drying as
> > air removes moisture from
> > one location more than the rest. Usually this is the
> > exterior of the wood.
> > The resulting shrinkage from the loss of moisture is
> > unable to occur because
> > the interior wood still contains it moisture and
> > it's original size. When
> > using a true ( partial) vacuum to remove moisture,
> > the wood is not drying
> > from the outside in. As the pressure drops the
> > moisture, in a pretty uniform
> > sequence, aspirates the moisture into gas which
> > escapes the wood.
> >
> > This process is accelerated by heated wood. This is
> > the only difficult part.
> > There are expensive heating blanket made
> > specifically for vacuum kilns, but
> > they represent a significant invest in the make-up
> > of the chamber and the
> > heater itself. Any heat source has to be contact
> > only. Remember that a
> > vacuum insulates and normal convection does not
> > convey heat. Radiant heat
> > ( light in various forms ) heats only the exterior
> > and may cause uneven
> > drying. All we do is pre-heat it just like an oven
> > and try to get the vacuum
> > pulled down while there is still some heat in the
> > log. It will not cool down
> > much after the vacuum has removed the air.( think
> > about a thermos jug ) When
> > you heat it up you have to let it remain heated for
> > several hours to insure
> > that the interior of the log is the same temperature
> > as the exterior.
> >
> > You can get serviceable vacuum pumps off eBay for
> > $50 bucks if you are only
> > going to do it a time or two. The actual original
> > purpose of the vacuum pump
> > is inconsequential, only that it will pull a 22" or
> > better vacuum and run as
> > required for several days. the drying time will
> > depend on species, size, and
> > too many other factors to name. But the thumbnail
> > measuring method of choice
> > is to weigh your entire contraption. If your log is
> > of any size there will
> > be a drastic weight change ( usually a hundred or
> > two pounds) as it loses
> > moisture. When your assembly stops losing weight,
> > your done. At lest as far
> > as you can go without mortgaging the house.
> > Commercial kilns dry 8/4 white
> > oak for about 48 hours at 22" vacuum. Almost zero
> > checking /splitting and a
> > very uniform 6% moisture content.
> >
> > Woodmizer ( the same folks that make the saw mill)
> > used to sell some light
> > commercial vacuum kilns and are a great source for
> > technical info.
> >
> > All that being said, if you can find it, aromatic
> > cedar is real forgiving
> > the same day it is cut. We are in the middle of a
> > 2000 piece run of
> > "spirits" about 20" tall and 4" thick through the
> > nose area. We produce
> > about 50 a day out of aromatic cedar that is often
> > sawmilled on the same day
> > we mount it on the machines. We have an occasional
> > loss from internal
> > checks, but they seldom to appear to be from drying
> > in the wind of the
> > router motors, more like internal stress cracks with
> > some resins visible.
> >
> > I also have a friend that is about to try Vacuum
> > bagging a log just like you
> > were gluing laminate and putting to in a hot box in
> > the sun. I will be
> > curious to see how it comes out. In theory it should
> > work the same.
> >
> > And as said in the previous post, if you can stress
> > relive the back, that is
> > always going to give you a more long term stable
> > product.
> >
> > Sorry for the oration, I get asked this from time to
> > time and just hadn't
> > had a forum to share it on.
> >
> > Best of luck and let us know how it goes.
> >
> > Phill Pittman
> > digicarve at verizon.net
> > www.masterwerkes.com
> >
> > ----- Original Message ----- 
> > From: "RAY MIGHELLS" <raymighells at earthlink.net>
> > To: "[Woodcarver]" <woodcarver at six.pairlist.net>
> > Sent: Monday, June 21, 2004 6:31 PM
> > Subject: Re: [Woodcarver] drying a 10" log
> >
> >
> > > To make a DONATION to the Mailing List using
> > PayPal OR regular mail, click
> > this link:
> > http://wwwoodcarver.com/WWWList/WWWList.html
> > >
> > > Hi Ray;  What kind of wood?   How dry is it now?
> > What are you going to
> > > carve on it?  Many woods are easier to carve
> > "green".  Keep it wet with a
> > > spritz bottle of water, cover it with something
> > wet/damp, and wrap in
> > > plastic when not carving.  Depending on the depth
> > of your carving,  you
> > may
> > > have to hollow it out from the back.  There's a
> > lot of grain tensions in
> > > different degrees of stress,  so even if it is dry
> > when you are finished,
> > > the seasonal changes can have distastrous effects
> > if the tensions are not
> > > somewhat compensated by relieving the back.  A PEG
> > treatment will help
> > some.
> > > Happy carving and good luck  Ray Mighells  6760 Rt
> > 417 Killbuck NY 716 945
> > > 0098 Please view my work at:
> > http://www.picturetrail.com/razaxnstuff
> > > ----- Original Message ----- 
> > > From: "Fishley, Ray (IS - Municipal Engineering)"
> > > <Ray.Fishley at City.Saskatoon.Sk.CA>
> > > To: <woodcarver at six.pairlist.net>
> > > Sent: Monday, June 21, 2004 5:27 PM
> > > Subject: [Woodcarver] drying a 10" log
> > >
> > >
> > > > To make a DONATION to the Mailing List using
> > PayPal OR regular mail,
> > click
> > > this link:
> > http://wwwoodcarver.com/WWWList/WWWList.html
> > > >
> > > > I would like to carve a 10" x 12 foot log.
> > > > I am looking for away to dry it so that it does
> > not crack or check.
> > > > I was thinking of drilling a 1" hole through the
> > center of it and
> > > connecting
> > > > a vacuum to it for a few weeks.
> >
> === message truncated ===
>
>
> =====
> Lynn E. Diel
> Columbia, MO
> Website: http://carvers-creek.com
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