----- Original Message -----
From: "Lew Hodgett"
Newsgroups: rec.woodworking
Sent: Wednesday, April 07, 2010 11:53 PM
Subject: I've Got A Bone To Pick


Currently the NYW is running a rerun of Norm making a small, 32" diameter,
table from recycled pine.

The stock for the table top comes from a piece of 12" wide barn siding,
from which three (3), 36" long pieces were cut to make the top glue-up.

So far so good; however, as would be expected, the board was cupped.

Norm's solution was to make a kerf cut on the concave side of each board
about 2/3-3/4 thru the board.

That works for me with the following caveat:

When the top is finally glued up and cut to size, the kerf cut will still
be visible.

Norm proceeded to surface the boards by pressing down on the feed rollers
to flatten the board while going thru the planer.

Next these boards were jointed, and biscuits were added prior to the glue
up.

While the top was in the clamps with the glue still wet, Norm proceeded to
fill the kerf cuts with an epoxy putty to strengthen and stabilize the top
blank.

Now comes the bone.

Trying to machine these boards before the kerf is filled and allowed to
solidify, is like trying to machine a flexible piece of "stuff".

You mean like machining material 1/4" thick? Not a problem. 1/4" is not
all that flexable unless you force it.


How he managed not to close the kerf cuts with the glue-up in the clamps,
I'll never know.


Remember a properly prepaired surface or edge does not need much pressure to
insure a proper glue joint. The clamps need only be tight enough to keep
the boards from slipping out of position while the glue cures.


OTOH, if each individual board had been clamped to a flat surface or even
curved cauls that would force the kerf cut open, much like a keystone or
trapezoidal cut, then filled with epoxy putty and allowed to cure, you end
up with a stable board which makes future machining easier.

You can do that too.

Sorry for sending dirrect.