Walnut Burl Help

[LONGBOWKID]

Need some advice here, I have 2 medium sized walnut stumps, with about a foot or two of root still attached, I want to get them cut down and get some burl walnut for knife handles.

My question is once cut, how long will it take to dry?

Also what is the best way to go about handling it? Any special needs for it?

Thanks in advance, hoping for advice from yall that have handled it before. ALL advice needed. Never attempted to work with walnut burl.

Thanks in advance,

The Kid

[chiger]

Hey Kid,

Having spent tooooo many years as a hardwood lumber inspector, I might be able to help you with this one.  

If you put the pieces in a nice dry place with an air space around each piece that's equal to the thickness of the piece, it should reach ambient moisture content in 45 to 60 days.  In Alabama will be about 25 - 29 percent, depending on the time of year.  The length of time in days depends on the thickness of the pieces.  And because it's root burl, it takes longer, so I'd assume the far end of times.  

After it reaches ambient moisture, no more water will come out without help.  Dry kiln lumber is usually about 7 percent.  So you can see there is a way to go.  If you take it out too fast the wood will do what is known as honeycomb.  No, I'm not kidding.  That's what it's actually called.  It's a nasty little defect that is kind of like a split in the end of a board but worse because it happen all through the wood.  It just shows up as little dimples in the face of the piece, but there's a big void in the wood under it.  Not good!

To avoid this, you need to apply low heat and air movement for a long time.  In the case of walnut burl, I'd guess about 12 -14 days of about 120 - 140 degrees.   Dang...this is getting to sound complicated.  ;~)  

And it kind of is, but there is a simple way to do it.  The lumber producers do it by applying vent fans and live steam boilers or some similar heat source at an exact temp of 160-180 for the kind of wood across lumber that is stacked in layers separated by sticks.  

You can do it for a few bucks and a trip to the local hardware.  Build a three sided box, say a foot wide, foot tall and 3 or 4 feet long that's open at the top and both ends.  The size is up to you really, but it has to be big enough to hold all the pieces with the same air spaces around them as before.  

Elevate one end a foot or two above the other.  The more the better as long as the pieces can't slide and fall.  Arrange the pieces on dowels or sticks inside.  Put some heavy duty aluminum foil over the open top.  Place a heat lamp or light bulb if the box is small at the bottom of the lower end.  The heat lamp will heat the air inside the box.  The hot air will rise to the open upper end and that in turn will draw new air in around the heat lamp.  

You may need use more tin foil to cut the hole size down on the uphill/outlet end to keep the temp up to that 120 -140 range.  But even if it's a little low it will just take longer to dry.  Just don't let it get over 140 or so.  

I'd also dip the ends (end grain) of every piece in paraffin wax to reduce splitting and cracking. You want the moisture to go out the face and sides, not the end grain.  

Ok, that's as long winded and murky an explanation as I can manage at the moment!  ;~)

I hope that's what you're looking for.  Home drying of wood is kind of a pain in the rear, but it can be done.  Most people will just send it off cause it's so much easier.  But either way, you should never use wood that has not been kiln dried and/or stabilized.  It will crack and/or shrink eventually.  

If you have any questions, I'll be glad to help.  Oh you might want to do a search for kiln drying times and temps for hardwood lumber.  I'm just kind of going by very old memories.  But those are pretty close and very conservative.

[LONGBOWKID]

WOW.. Thats all I can say...


Very troublesome, I had no idea it would be THAT difficult and complicated.

To start with I need to cut it. Right now its just a stump and root ball. But I know the pretty stuf is in there! What do you reccomend cutting it with most? chainsaw?

 Having second thoughts here, but I'll get around to it eventually.lol

Thanks chiger, great info by the way.

The Kid

[Lin Rhea]

Very good explanation Chiger. This should work for most woods. It is very time consuming, but worth it. Think of the bulk of material it will yield.
                        Lin

[d. ward]

LBK he's not jokeing you it's a little work.I go to Crosscut hard woods here in Seattle often and they have kind of the same process going full time in the back of the warhouse.But as Lin mentioned it's well worth the time spend salvaging it.bowdoc

[kbaknife]

Chiger, something I have always wondered about and you are apparently the one to ask -
Once a piece has been dried to the lower percentage of moisture, will it want to return to the ambient % by absorbing moisture from its surroundings, or will it stabilize at the lower % ??
What is the best way to store dried handle blocks to keep them dry?

[tippit]

chiger, That was a great explanation!   Also if anyone has made selfbows, Paul Comstock in his book Bent Stick has a pretty neat way of drying staves with stove pipe and a light bulb.  I also have a heat box that I'll dry up my staves.  I bet if you post this over on the Bowyer's Bench Forum, You'll get some easy ways to dry wood too...tippit

[d. ward]

I've dried vine maple behind the fridge there's always warm air comeing off it's compresser and the fan from the auto deforst blows the air around.If you use a bow laminating hot box with light bulbs you will need to add a fan for dring wood to blow the moisture away.bowdoc

[chiger]

Hey guys,

Sorry to be so slow gettin' back.  Middle of second BP season here in KY...you understand.  ;~)

Kid,

First, didn't mean to put you off the whole ideal.  You can do this!  Just need to know a couple things about lumber and be patient is all.  And there is no rush.  It'll start drying in the stump.  Just wash off the dirt and then keep it out of the weather.

Chainsaw will work fine...if you're real comfortable and safe with it.  Stumps have a nasty habit of growing around rock, steel and all manner of thing that will cause a saw to kick back...causing GREAT bodily harm!  ;~0  Otherwise I might use a long blade on a saws-all.  

Either way, just be careful and keep your hand on top of the saw.  And you're right, there should be some very pretty wood in it.  People call it root burl, but most often it is just very wavy grain.  Which is still very cool.  

The actual hardwood inspectors definition of burl is..."A swirl or twist in the grain that occurs near a knot, but does not contain a knot."  Sometimes roots have those little round eyes in them, sometimes they don't.  But it's always more interesting than the rest of the tree.  But like bowdoc and Lin said, it's well worth it.  So go for it!  

Oh, in anticipation of how do you know what the moisture content is question.  There is an old school method if you don't have access to a moisture meter.  It involves a microwave oven and a kitchen scales.  When you get to that point, let me know and I'll be glad to write it out for you.  

Karl,

I'm not the last word on wood Karl.  Just a wore out old hardwood lumber grader.  ;~)

Yep, you're right.  It will try to take back on ambient moisture.  Especially through the end grain and on the surface.  But the thing is, it took an extraordinary mechanical process to get it to let go that moisture and it takes a extraordinary mechanism to put it back fully.  That's why simple sealing methods like varnish and waxing will make hardwoods last hundreds of years.  The stuff you do to your knives may last forever!

Too tell the truth though, untreated dried lumber will probably rot before it fully absorbs enough moisture to get back where it was.  I'd keep it in the driest place in your shop or house, usually up high near the ceiling. And where you can keep it separated all the way round so air can flow well around it.  It may take on a little moisture at the surface, but it will come off as you work the wood.  

That's the other thing I'd suggest.  Leave blanks you'll be storing a while a little large.  Just in case it's longer than you think.  And always seal the end grain of smaller pieces with wax or something.

Hope that's what you were talkin' about Karl.  Once the wood is dried the cells collapse and hardwoods get pretty stable.  It's hard to put much moisture back in just out of the air.  At least it's a slow process.

tippit,

The stove pipe thing is a great ideal.  Hadn't thought of that.  It's simpler and it ain't flammable!  I'm thinking of trying my hand at making a bow before long.  I may try that.

I bet your right about the other forum.  Ancient bowyers were using heat to temper wood for bows when the rest of mankind was figuring out how to make fire!  ;~)

Hey bowdoc,

I'll bet elevating on end up a lot higher, like 20-30 degrees, will keep the air moving pretty good in a stove pipe too.  I know it won't have as much head room for the moist air to evacuate, but the hot air is going to go out the high end.  And the warmer the air the faster it will move.  Maybe a smaller wattage heat lamp bulb?

[kbaknife]

That's great info!
If I get a large blaock of something, I normally cut it into oversized pieces, seal the ends by dipping them into melted parafin, and then place them on a rack in the ceiling of the shop near the forge area.
I got to thinking last night that after I am sure the blocks are dried out, I may store them in some large zip lock freezer bags and place in a snap-lock  plastic storage container.
I think this would ensure long term stability.
Maybe even put some of the silica gel paks in with the blocks to absorb any foreign moisture!

[d. ward]

Crosscut has the big fans at one end of the building.I think they really just keep the air moveing to alow even dring more then anything else.The air is not all that warm 55-60 deg.somewhere in there.Lower wattage heat lamp would make since.I gotta tell you guy's if your ever in Seattle forget seeing the sights and sounds of the city.I'd take the family to Crosscut Hardwoods for vacation.bd

[chiger]

LOL bowdoc.  

I've spent too many years in saw mills making a livin' to want to vacation there, but it is very interesting technology.  I can absolutely see the fascination with it.

I think what your are talking about with the fans, if you're talking about huge buildings with tens of thousands of board feet of lumber in um, is dry storage and pre drying sheds.  We use those around here too.  We use them for storing kiln dried lumber and as pre-drying sheds for lumber that's going to be kiln dried.  If it's high end or needs to dry faster than it will do in a open air shed that's where it usually goes.  

You're right.  The whole key to dry storage is air movement.  If you don't let the air move around the lumber the difference in temperature between the air and lumber will cause condensation and in turn the humidity to go up.  

I've seen fog form in those sheds when they'd load in a fresh, out of the kiln batch into the building and forget to turn on all the fans.  It's cool!  Open the door and fog rolls out.  Can't see 20 feet!  Yard manager didn't like it much though.  ;~)

Hey Karl,

I've heard of guys doing what you're talkin' about and storing the pieces in a big self defrosting freezer.  If I were going to wrap them in plastic anyway, I might try that.  The colder the air the less moisture it can hold.  And self defrosters use vacuum to suck out moisture.  Might be the safest thing you could do with high priced stock actually.  

Just an ideal.  Haven't tried it, but it makes a lot of sense.  The driest place on earth is Antarctica.

[LONGBOWKID]

Well guys I have a connection with a guy that owns a small sawmill, and he agreed to cut them up however I like. So thats set. When I get that done, I will build the heat box chiger talked about, as I am impatient and cant wait for it to dry on its own. hah

Thanks for all the help and encouragement guys

[LONGBOWKID]

Just an idea for size, I can pick both up, but im holding the one I dont have to risk a hernia to pick up.HAH...Probably 60-75lbs, the other close to 150lbs or more.


Are these good candidates?

One has a hole all the way through it, the other is fairly solid.

 

 

 

[d. ward]

That will make some fine looking wood right there.You may want to romove as much of the soft wood as you can as soon as you can.That will help stop the sprend moisture or wood rut.Good looking stuff...bowdoc