Conference noted::woodworking_and_tools

I've read all of 21.* and have a question about painting the end of wood
to be dried.  I have a 32" diameter slice of an oak tree, cut to 4" thick.  We
want to make a coffee table out of it, but keep the natural grain and color.

Do I need to worry about sealing the ends (top and bottom) while attempting
to dry this piece?  What can I use that will not destroy the look of the oak?

Dave

    The main problem is checking, differential drying will cause large 
    cracks across the growth rings from drying stress. I've heard of
    using paraffin to seal the end grain, your case top and bottom you 
    gotta do both. Another option is to put it in a plastic garbage 
    bag and leave enough of an opening to let air exchange. I've done
    this with bowl blanks and on red oak it forms mold on the wood, I 
    wouldn't recommend it. Since you did say it sat since 94 and you
    just cut it up you do stand a good chance of not having too many 
    checks. Be carefull about painting the wood especially if its red 
    oak. I don't know how you going to plane the top down but you'll have
    to go quite a way to get the paint stain out..... Also the bark is 
    nice but I think you'll find over time that it will fall off. It also
    is a nice hiding place for bugs. I wouldn't want it under my bed....
    
    Good luck!
    RT

	Bruce Hoadley (not sure of spelling) wrote a book titled
"Understanding Wood" which might be interesting reading.  One of the
problems with drying wood is it contracts at a different rate radially
than tangentialy.  The result is that your slice off the end of
a log WILL split as it dries.

	Some wood workers saturate wood with a solution of PEG to eliminate
the shrinkage.   Woodworkers Supply in Woburn will have books would give
guidance, and might sell it.

	The books usually suggest a year or more per inch of thickness
for air drying.  In my experience with thick oak, it may need more time.
An end piece might dry faster.   If you coat the ends, it may never dry,
it may just rot.   If the bark is tight and you get it in a warm dry
place you probably don't need to remove it, and it adds character.

	If you have a furnace room, that is usually the driest room in the
house, and stacking it there might accelerate the drying (and may violate
fire code).

	A solution to the splitting problem might be to decide you like
it and control it rather than fight it.  Make a single cut from the edge
to the center.  Then as it dries you will end up with something
which looks like a pie with a slice taken out.  After it dries glue in a
contrasting piece of wood and have a piece of art.

I'll check the library for that book (and others).  Our furnace and dryer are
in the same room, but there is no room for the wood in there.

The cracking won't be a major issue as long as it can be pieced back together.
If I attach sheet metal to the bottom, it should be held together okay once 
it's dried out.

Dave

Dave, the cracking that has been referred to here, will result in a 
`V' shaped split (probably a few actually) with a point near the center
of your slice and will probably be inches wide at the bark; clearly 
this could not be glued back together.

The Polyethylene Glycol (PEG) referred to will displace the water in the
wood pores, and usually results in no cracks/splits.  It does leave a 
waxy surface to the wood though.

Don't put the wood near the furnace/drier, heat will aggrevate the problem
by drying the surface of the wood too fast.  It is usually recommended to
keep the wood in an unheated and covered place to minimize the cracking.

Has anyone tried cutting a blank such as this 32"d x 4" thick like a pie,
drying and then glueing it back together?  Matching the bark up would 
appear to be the biggest problem.

Bruce

>The Polyethylene Glycol (PEG) referred to will displace the water in the
>wood pores, and usually results in no cracks/splits.  It does leave a 
>waxy surface to the wood though.

So it looks like I should remove the bark and then coat the top and bottom 
(the ends) with the PEG stuff.  Can I then sand it off and coat it with
a clear finish (decoupage?) once it's dried?

>Don't put the wood near the furnace/drier, heat will aggrevate the problem
>by drying the surface of the wood too fast.  It is usually recommended to
>keep the wood in an unheated and covered place to minimize the cracking.

It's either going to be stored in the house under a bed, or in the garage
in our hearse.  We're also located in the Atlanta area so it does get humid
in the summer - will that extend the drying time?

Dave

I believe that in the latest issue of FWW someone asked a question about this
same thing - drying a thick slab of wood cut off the end of a log.  I'll look
for it tonight and enter the reply (might have been from Hoadley) tomorrow.  I
believe that one thing that was said was that the wood should be treated with
PEG very soon after cutting.  As for painting the ends, I've never used PEG but
don't you have to soak the wood in it, not just paint the ends?

George

    I seem to remember reading in an old FWW that peg works by  replacing
    the moisture in the wood with the peg solution. You can't just paint it
    - you need to soak it. For a long time. Like a couple of months for
    your piece.
    

    This piece of wood is basically all end grain. It's going dry much
    faster than normal. This is the direction fluid normally travels through 
    the tree. Radial checking is the biggest problem your up against. The wood 
    density increase as you move towards the heart wood and the fibers closer 
    to the perimeter will generally shrink more. 

    I think your best chance might be to surface the top and bottom and
    seal it as quickly as possible. I'd use a pour on finish, I think it's 
    a two part epoxy. When your done it look like 50 coats of varnish only
    clearer. I'm sure you've seen this stuff used to finish bar tops.

    This should basically lock in the moisture and will take many years to
    stabilize, greatly increasing your chances for success. You might want
    to practice the finish technique on a small log end. You'll want a clean
    transition on the edges.  

    To attach the legs, I'd use metal leg mounting plates. They come
    with a 10-15 degree flare. The legs just screw right into the plate. Be 
    sure to careful address sealing the screw hole for the plates, maybe
    more epoxy in and around the pilot holes?  I think mortice pockets would be 
    too big a risk, a source of instability for checking to develop.
    	

    Disclaimer: I've never used this epoxy finish or PEG, which may work as 
    good or better than the epoxy. I think your chances will be improved
    but success is still uncertain. I have seen how quickly unsealed end grain 
    can cause checking on a green timber. 


    /Jim

    I don't think epoxy will work, could make matters worse. Epoxy isn't 
    too flexible and will probably seperate from the wood since the wood
    is "wet". I'd go for the PEG. What about "stress relieving" the bottom
    of the table top? Taking a circular saw and making .5" cuts across the 
    middle at various compass points? Just a thought.
    
    RT

	I finally remembered to bring this FWW Q/A in.  It regards sugar maple
but probably applies here.

Question:  I would like to cut a 2-in thick slab from a 3 ft. diameter sugar 
	   maple trunk to use as a rounded tabletop.  Can I treat the slab with 
	   polyethylene glycol (PEG-1000) to prevent it from splitting?  Is 
	   there another way?

Bruce Hoadley Reply:  I don't know of any other way to attempt stabilizing a 
		      thick, large-diameter disk of sugar maple.  If you 
		      decide to try the PEG - 1000 route, be sure that you are 
		      set up before you cut the slab.  The wood should not be 
		      allowed to dry out at all and should have as much of its 
		      original sap as possible before you soak it.
	
		      If you have not worked with PEG - 1000 before, I would 
		      recommend first reading about the procedure.  Patrick 
		      Spielman has written an excellent book on the subject, 
		      called "Working Green Wood With PEG" (Sterling 
		      Publishing Co. 1980).  Be aware too that the PEG-1000 
		      isn't cheap and that success is not guaranteed.  It 
		      might be a good idea to try the procedure on some 
		      smaller projects first.

		      With such a large disk a major problem is getting it
		      leveled and smooth after treating and drying.  If you cut	
		      the disk from the stump with a chainsaw, I'd recommend 
		      setting up a frame to make router passes across it to 
		      create a relatively flat surface before you treat it.
		      This will give you more uniform penetration of the
		      PEG-1000 and will reduce the work later.  You'll still
		      have plenty of end-grain sanding after the disk is dry.

			
	

Well, I have painted the ends of the 4" slab with latex paint (wood colored)
and will wait a few months.  I still have the 18" thick piece that I may
try PEG with, but maybe it'll end up as firewood...

With all this information I know how to do it right if I can find another
good piece of wood.  I think my friend may still have some up there so I'll
check.

Thanks for all the help and I'll let you know how the 4" slab turns out.

Dave

I'm reading a book called "The Art Of The Lathe" by Spielman.  Last night I ran
across a couple of paragraphs that are relevant to this discussion.

	"There are many disadvantages to using PEG.  It is quite expensive and
is difficult to finish.  Additionally, it does not work well with many
conventional finishes.  Some surfaces, if overtreated at all, will become greasy
and moist in environments with high relative humidity of 90% or above."
	"PEG works best on fresh green wood, rather than partially dry wood. 
PEG treatment does not work equally on all woods.  HEART WOOD OF HARD MAPLE AND
WHITE OAK ARE NON-TREATABLE.{emphasis is mine -gp} In short, the denser the
wood, the more difficult it is to to take an effective light PEG treatment. 
Treatment or soaking periods vary from overnight to two months or more,
depending upon temperature, concentration of the mixture and the woods density."|
	
	Spielman then recommends his book "Working Green Wood With PEG",
Sterling Publishing, for more information.

George