Yesterday I started out to glue up a top for a library table I got at the
local school surplus. The table was all solid oak except for a beat up
plywood top. Anyway, I figured it was a snap to make a solid top: Just face
joint, edge joint, thickness plane, rip and glue. No problem right? I guess
I had never tried to face joint 4/4 lumber of any length before. By the time
I got the 5 foot long boards face jointed and planed they were getting might
thin. Doesn't take much of a cup in a board to really take away the
thickness. So now I am left with a bunch of really thin (but flat!) boards
and I'm trying to figure out a way to save the situation.
I'm thinking of using the old plywood top and gluing down a thin solid top.
However, I know that the solid wood will move and the plywood won't. How
thin would I have to make the oak top so that it will act like a veneer?
Put more simply: How thick can veneer be and still act like veneer rather
than solid wood?
Any other solutions welcome as well as advice for the next time. Maybe just
start with 8/4 lumber ;-)
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Typical veneer is usually less than 1/32 of inch or so (give or take a few
hundreths). You'd have to be pretty skilled to turn the top into veneer
(plus you'd be wasting a lot of wood). Try a thick/wide edging around your
table panel. If you're down to a 1/2" board, glue 1" edging around it. The
edging can be as much as several inches wide. This will give it the
appearance of a much thicker top. Because of the wood movement of your main
top, you'll probably want to use a breadboard type joint on the ends.
Jim, I don't have the answered to your question but I know on engineered
flooring the solid wood layer is about 1/8th in. But, those are planks that
are only about 6" wide before the next tongue and groove which does allow
some expansion across a whole room.
As far as your flattening exercise, did you support the gap on the "under
cup" side of the board when you ran it through the planer? You need to build
a sled to do this so the rollers don't just flatten the board as it goes
through the planer and really does not flatten the board until way too many
passes have reduced the usable thickness. Perhaps this was not the issue and
the boards were flat after you used the jointer.. not sure of your sequence,
but just a thought.
Dennis Slabaugh, Hobbyist Woodworker
Without seeing how bad your starting lumber was, might I suggest:
1) Better grades of lumber are best to start with. FAS may cost more, but
it has better width, which means less sapwood, and no knots, which means it
doesn't twist around them.
2) Sight your boards and plan ahead. Rough cut to length with the
objective of eliminating the worst twist. As they normally sticker 6-8" from
the end, don't plan on using that in your long cuts. I like to work by
taking a touch from either high end versus trying to guess the middle.
3) If the board will ride flat through the planer, regardless of whether it
is flat (rough in middle or an odd edge, e.g.), it's ok to thickness.
There's a bottom that is seldom seen on every tabletop. Also, two straight
boards can take a lot of bow out of a board in between if you use good
4) I like 5/4 lumber for tabletops.
You appear to be at the point where anything you can do to salvage the
project is worth trying, even it does not confrom precisely to conventional
wood working wisdom ... IOW, what have you got to lose?
At this point, I would be tempted to buy a good sheet of cabinet grade Oak
Plywood, edge band it for the table top, and use your thin, but flat, boards
for another project.
Depends upon the wood and width, but on 12- 24" bookmatched widths, I've had
luck bandsawing to 3/16" and using that as a veneer on an mdf substrate
Although I prefer thinner for most veneer applications, IME, 1/16" is
pushing the edge for "thin" in a home shop with a well tuned planer, sharp
blades, and some type of carrier jig ... a drum sander is ideal, if not
almost a requirement, for this situation.
Commercial veneers are generally much thinner, but 1/16 - 3/16" thickness
should be OK providing your substrate is stable, ie good ply or mdf, and you
use good glue.
Pick your lumber with more care. If you can't take 4/4 down to 3/4", you
made your mistake in purchasing.
For table tops I always try to start with 5/4 if possible. Short of that,
buy 3./4" dimensioned, straight as you can find and use it right away.
Keep in mind that "perfectly flat" is not always achievable and a slight bow
can usually be forced out of individual boards during glueup of a panel
without any ill effects.
I just glued up a maple butcher block counter (yes another one). I went the
other way, not having a jointer. I glued them (1x2 s4s) up with the slight
warps in them resulting in some rough joints and took it all out later with my
belt sander. I turned a lot of wood into dust but only the wood that wasn't
working with me.
BTW "Norton" blue sanding belts, accept no substitute. The crap I got at Harbor
Freight weren't worth the time to load them on the sander. I got more done with
one 50 grit Norton belt than a half dozen HF belts and it still has some life
I followed up with a 150g belt and then 150 in my ROS. It came out great.
I'm not at all sure how you are going to recover and still use the stock you
have but you should note that you are operating under a misconception if you
think veneer doesn't work like solid wood.
When you veneer the top of a substrate it is usually advisable to also apply
a veneer (it need not be of the same species so a cheaper one can be used)
to the bottom of the substrate to counter act the bending and twisting the
top layer can cause to a substrate.
Just a thought.
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