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54" Douglas-fir log round - processing

Started by eott, December 17, 2012, 01:34:57 PM

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eott

 

  

 

Hi all, I've been reading through all the posts I could find for preserving cross sections of logs. Lots of great information out there. Thank you. I have a 54"-diameter Douglas-fir cross section that I would like to use as an educational tool at our government office here in Idaho, USA. Unfortunately, I think the PEG treatment is out the window since it'd be awefully pricy to do on something this size. If you have any input or have gone through a similar process, please speak up! I'd greatly appreciate any suggestions, tips or stories.

More on the tree: It is freshly cut. One side has the felling face-cut so it's only about 8" thick. The other side is about 1.5' thick (so the cut sides are not parallel). This tree seems to have grown rather quickly for an Idaho tree. As you can see from the picture it has an old wound that goes almost to the pith that was compartmentalized, leaving a seam of bark into the middle.

I am looking for input on:
1) how to dry/treat?
2) how thick I should leave the cookie?

Thanks for the help in advance,
Eric

beenthere

Welcome to the Forestry Forum.

Looks like quite a project you have there.  8)

You are wise to forget trying to PEG treat it.

Keep the end grain wet until you decide what thickness you want and then get it cut to that thickness. After that, dry it as slow as possible and just take the drying checks and splits to be part of the final cookie.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

shelbycharger400

I have sliced up stump slabs anything 16 to 26 in dia.
seems around 2 to 4 inches works well, dry as slow as you can!! 

best bet is to peel the bark off, leave it whole for a while, seal the ends and let it sit for a few years in a shed, then saw it.

jueston

i have no experiance with this, so maybe i'm wrong, but it seems to me if you took a bandsaw and cut from the edge to the center in one spot, that would allow the wood to move radially and relieve a lot of the stress, this might sound like it would be unattractive but i think it would be more attractive to have one intentional cut then checks all over the cookie.... just a thought....

woodhick

Not that I have done the following but read about it somewhere.  I think Dr. Wengert may have done an article on it.  He may follow up here later.
   You do not say how thick you need the finished piece to be.   I would cut 3 or 4 slices off 2-3" thick.   Make a mark somehow so you can reference or orient them all the same later.   Make a cut from the outside into the center pith on one slice.  On the next slice do the same but not in the same place say 1/3 rd of the way around.   Cut them this way and allow them to dry.  After they dry you can cut a "pie" piece from one disc that will fit into the other and glue it back in.    Not perfect but should give you a "whole" piece when done.  Hope thats not too confusing.  Not that hard but hard to type out explanation.
Woodmizer LT40 Super 42hp Kubota, and more heavy iron woodworking equipment than I have room for.

kderby

Looks like a typical red fir from E Oregon/Idaho.  The old wound likely tells a good story.  I do not have a good drying idea other than time.   I wonder if you chainsawed if in half if that would direct the stress as it shrinks?  That would also let you place the parts on a band mill and get an even/smooth cookie thickness.  My mill can cut just over 24 inches.

I think that how ever you accomplish the process the educational value wil be retained.  As a kid I always liked these stump display cookies.  Look what I do now.  Sawdust in the veins or a plot?  Nature or nurture???  Both!

Kderby

kelLOGg

Gene Wengert (on another forum) recommends soaking in denatured alcohol. Google it (and him) and I bet it pops up quickly. I just posted on the sawmilling forum about using it on small cherry cookies.
bob
Cook's MP-32, 20HP, 20' (modified w/ power feed, up/down, loader/turner)
DH kiln, CatClaw setter and sharpener, tandem trailer, log arch, tractor, thumb tacks

red oaks lumber

welcome to the forum,looks like an interesting project.
the experts think i do things wrong
over 18 million b.f. processed and 7341 happy customers i disagree

Den Socling

I would get a pail of Anchorseal and paint the whole cookie. The old wound may actually relieve some stress.

Jay C. White Cloud

Hello Eott,

You have gotten excellent advice so far, there isn't much to add.  I can hit the highlights and add my two cents.  I have several rounds drying or to be processed now, in elm, black oak and white pine. Here goes.

Dry as slow as you possibly can, the longer the better.

Seal the wood to slow the process, I use "Land Ark," for sealing and finishing.

Don't go thinner that 60 mm (about 2.5") if you do, you must put a backing material on it.

If you have access to a pond or body of fresh or "natural" black water, put it in there for 6 months to a year.  The drying results after are great!  If you can store it there longer the better.

"Kerfing" the disk is an option, but you then have a pie piece to deal with, that does not matter for some applications.

The last, this is challenging and is called "strong backing," is to cut you disk out, choose the side you want to have as your finished surface, then flip it over.  On this underside, (disk should be 75 mm (3") thick minimum for this application,) you are going to come in from the outer edge about 75 mm to 150 mm (3" to 6") and draw a line all the way around.  Now, starting in the center, router down a recess at least 25 mm (1") down all the way to your buffer edge line.  In this space you are going to epoxy/glue a "strong back," this can be ply wood, alternating planks of wood, even composite material if it is structural solid (not my choice.)  This method can be very successful and done with wood that is only "surface dry." If you do not use epoxy, it must be some form of structural adhesive rated for "extreme loads."  You have, if done correctly, about a 90% chance of not getting any surface checks of any magnitude.  You must oil the wood as soon as the adhesive set up!

Good Luck,

Regards,

Jay

P.S.  I did notice in your photos that it appears you have some "bark inclusions" in your chunk of wood.  Long term drying or not, you will need a "strong back," application most likely or the the piece could self destruct from uneven tensions in the wood.
"To posses an open mind, is to hold a key to many doors, and the ability to created doors where there were none before."

"When it is all said and done, they will have said they did it themselves."-teams response under a good leader.

GeneWengert-WoodDoc

Great advice so far.  The idea of cutting a pie shaped piece from an adjacent disc was pubished in SAWMILL & WOODLOT...it really works well.  For some species, alcohol works well.  Coastal DF should be a good one to try it on, but the heartwood maybe too impermeable.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

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