RE: 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".

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

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.

As far as the final kerf cut being visible in the table edge is concerned, Norm used a poly/stain product which, IMHO, is basically the same as paint, so maybe he was able to hide the epoxy in the kerf.

BTW, forgot to mention, need some tape to dam up the ends of the kerf cuts and prevent the putty from oozing out.

OK, I've picked the bone.

Off the box.

Lew

Reply to
Lew Hodgett
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Ah, So there's the real reason for this thread... Mr. Hodgett wants to push EPOXY! ; ) Seemed like a valid bone to pick though.

Reply to
Bill

Who knows? Maybe the top will not be planar in a few months. Norm rarely goes back to critique past projects. But the bottom line is, he's a force for giving a lot of woodworkers inspiration and usable techniques, despite, a few brads until the glue sets.

Joe G

Reply to
GROVER

I would have just ripped the boards where he kerfed them and glued it up and then flatten it. You could keep them collated and probably barely notice the joints. I work with a lot of pine. I am processing a few thou feet right now. It is mostly beautifully flat 12" wide stuff but a few pieces do cup (like the 12 footers I left in the rain) and they just get selected to be ripped down into thinner pieces.

Reply to
SonomaProducts.com

--------------------------------- That was suggested as an option; however, it was rejected in favor of the kerf method.

For this application, I'm with you.

"Rip & glue" would have been my approach.

Lew

Reply to
Lew Hodgett

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

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

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.

You can do that too.

Sorry for sending dirrect.

Reply to
Leon

"Leon" wrote::

----------------------------------------- It is such a simple thing to avoid by filling the kerf FIRST, not LAST in the sequence of operations.

---------------------------

--------------------------------------- Clamping pressure is a relative thing.

For example, epoxy requires less clamping pressure than TiteBondII.

The point is that the clamping pressure will provide off center loading on the kerf forcing it to close by some amount including completely closing the kerf.

Again, so simple to avoid.

It is simply using the proper sequence of operations to eliminate problems before they develop.

Lew

Reply to
Lew Hodgett

But doing that can be easier said than done...trust me!

Bill

Reply to
Bill

So use masking tape. What will be fine.

Then you would simply be clamping too tightly.

Reply to
Leon

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