[Woodworkers] Turning Burls

Fri Dec 31 16:45:40 PST 2021

👍👍Good info.. Thanks.

On Fri, Dec 31, 2021, 6:39 PM Richard Allen via Woodworkers <
woodworkers at lists.sawdusters.org> wrote:

> Hi Chuck,
>
> Turning a burl is a lot of fun.  Turn it wet.  Your choice is to turn it
> thick and dry it slowly or turn it to finial thinness (1/4” or less and an
> even wall thinness) and dry is slowly.
>
> Drying slowly can be done several ways.  If you want to preserve a natural
> edge then the drying process is more limited.  You can’t use anchor seal
> (emulsified wax) to slow the drying process because you can’t remove that
> stuff from the natural edge.  The two methods I have used are:
>
> Put the turning in a brown paper bag along with some of the wet shavings.
> At some point you will need to remove the wet shavings but you can keep the
> turning in wet shavings for weeks without degrading the wood.  Once you
> eliminate the wet shaving put the turning is a brown paper bag along with
> one or two paper towels.  Every day remove the turning from this bag and
> put it in a dry bag along with dry paper towels.  Turn the wet bag inside
> out and hang up the wet paper towels.  These wet things will dry and you
> will use them the next day. You may need more than two sets of the bags and
> paper towels.  Keep doing this daily routine until the paper towels come
> out dry.  Then switch to the exchange once every 3 or 4 days.  In a month
> you may find the wet paper towels can take a week to become wet.  At this
> point you can likely eliminate the paper towels  but keep exchanging dry
> bags weekly for a few months.  To tell if the turning has dried kiss the
> turning.  When you press your lips to the turning you will be able to
> detect if the turning is cool.  When the turning no longer feels cool by
> the kiss method you can feel confident that the turning is dry.  I would
> leave the “dry” turning out of the bag for a couple of weeks to insure it
> is indeed dry.  At that point you can return the bowl if you left it thick
> or hand sand if you turned it thin.  Expect the drying process to take  few
> months if turned thin.  Expect the drying process to take 6+ months if
> turned thick.  I know this all sounds like a lot of work but it is actually
> a lot of attention and very little work.  If you try to rush the drying
> process you will less success.
>
> If you turn thick then the wall thickness hound be even from rim to bottom
> and at least 1” thick.  The rule is wall thickness of 10% of bowl
> diameter.  For a burl this thickness should be a little more (maybe 15%).
> Please note that a 6” bowl should be 1” thick even though the 10% rule says
> the thickness should be less.  The primary reason for the thickness is that
> there will be enough wood when dry and warped that the bowl can be returned
> round.  The two benefits of thick turning are, the finished bowl will be
> round and you can sand on the lathe.  The detriment to the thick turning is
> that there are more failures in the drying process.
>
> Please note that the chances of drying failure for unturned wood is very
> high.  Maybe a 20% success rate.  The success rate for thick turned bowls
> is dependent on the drying attention.  If good attention Is provided you
> should have 80% success.  BTW success with slow drying using emulsified wax
> coating is closer to 90%.  Success for thin turned bowls, given that
> attention is provided should be 85%.  Cottonwood tends to dry well and I
> would expect a much better Ives’s rate.
>
> You can use a plastic bag instead of a brown paper bag.  The process is a
> boy longer and the success rate is higher.  Starting with a plastic bag for
> the first couple of weeks can help.
>
> I would turn between chuck face and live center.  This gives you the most
> positioning options.  Note that burls tend to follow a cone shape with the
> wide part of the cone being at the bark and the point of the cone being
> towards the center of the tree.  You want to preserve as much of the burl
> as you can.  So the bottom of the bowl should be the bark side and the top
> (opening) of the bowl should be the center of the tree side.  There is some
> variation in the internal shape of the burl and cotton wood tends to be
> more ball shaped and less cone shaped.
>
> As I said the blank starts out between the chuck face (not clamped by the
> chuck but pressed against it) and the live center.  Start with the bark
> side toward the live center.  Adjust the mounting so that the blank runs
> mostly balanced.  Turn the blank round and put a foot on the live center
> side.  That foot will be clamped into the chuck in the next stage.
> Once mounted in the chuck use the live center for support and turn a foot
> on the bowl mouth side (live center side).  You will now have the blank
> with tennons on the foot and in the bowl.  Now mount the blank on the
> tennon on the bowl mouse side.
>
> Again use the live center for support.  Turn the outside of the bowl,
> removing the live center once you have established most of the outside
> shape so that you can refine the tennon that will be the foot of the bowl.
> If turning thick do not turn away the dimple left by the live center as
> that well help when mounting after drying.  If turning thin make the bottom
> mostly finished.
>
> Now mount the bowl on the foot tennon in the chuck and hollow out the
> bowl.  Remember that an even wall thickness will help to yield success in
> the drying process.  As this is wet wood you should turn the bowl all at
> one time.  A wet bowl sitting on the lathe overnight will almost certainly
> develop cracks.  You can wrap the bowl in plastic if you must walk away for
>  couple of hours.  You can remove the wet bowl from the lathe and store in
> a pile of wet shaving overnight.  Please note that remounting the wet bowl
> the next day will present some “challenges”.
>
> If you can live without the “natural” edge the turn are described thick
> and put a coat of emulsified wax on all surfaces.  Put the waxed bowl in a
> cool dry place out of sunlight.  Leave the drying blank undisturbed for
> several months.  Use the kiss method to determine dryness.  Turn the thick
> bowl round but not to finish thickness and let sit for a couple of days.
> If the bowl remains round it is dry.  If the bowl goes oval leave it to dry
> more for at least a month, two months would be better.
>
> I know this is a LOT of info and I am sure I am missing many critical
> parts of the process.
>
> I can always try to clarify anything I have mentioned.
>
> Turning a green burl and turning green wood is more the same than it is
> different.
>
> On Dec 31, 2021, at 5:42 PM, chuck.steger--- via Woodworkers <
> woodworkers at lists.sawdusters.org> wrote:
>
> 
>
>    Happy New Year to everyone! I hope your holidays were good! Mine sure
> were. 2021 was a year of turning first for me … I turned copper (with help
> from this wonderful group), I turned finales & icicles out of resin for my
> Christmas ornaments, and did the same using shop-made turquoise finales &
> icicle tips.  Now, I want to try turning a burl.
>
>    I cut a burl a few days ago from (I think) a cottonwood tree.
> Cottonwood is a softwood so not sure if that matters. Would appreciate some
> guidance on:
>
>    - Turn green or dry?
>       - From what I understand, if you turn green, it’s easier to turn.
>       You then have to dry it where it could warp. Some people leave the warp (or
>       crack) and some fill cracks and turn round when dry.
>       - How long will it take to dry?
>       - Wall thickness if re-turning? Wall thickness if not? Or, is that
>       hard to say until you see it dry?
>       - Advantages to turning dry? Anything special to do when drying.
>    - The bottom is rough from the chain saw cuts so I need to flatten,
>    right?
>    - Face plate or will a screw chuck work?
>    - Anything else I need to know? I’d like to do a natural edge type
>    bowl.
>
>
>
>    As always, thanks!
>
>
>
> Chuck
>
>
> _______________________________________________
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> _______________________________________________
> I want to be one of my friends for a day so I can see how cool it is to
> hang out with me.
> Woodworkers at lists.sawdusters.org
>
> To unsubscribe from this list -
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>
> Address to contact the list ADMIN staff -
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