Any tips on gluing up thin stock (1/2") panels and keeping them from
popping out of alignment under clamp pressure? I'm making a small 20"
square cherry panel (out of some boards I rescued from the burn pile
because they were horribly twisted with my newfound jointer knowledge, but
the twist was so bad that I could only salvage 1/2")
I'm using one clamp above and two below (pipe clamps), and it keeps
wanting to pop out of flat... any tips?
I just used a method where I cut mortises in two scrap strips and slipped
them over the ends of the strips I was clamping, parallel to the clamps.
Worked fine on 1/8" thick material, so it ought to work on 1/2".
I just glued up a panel that was also 20" square. I put two clamps below
and one clamp above. Then I wrapped each end (parallel to the clamps) with
wax paper and clamp another board using C-clamps along the edge to keep
everything in alignment. Even then, it is hard to get it absolutely
Get a piece of flat thickish ply or mdf, a few inches larger than the panel
all round. Nail a couple of parallel cleats to it, the cleats being exactly
the same distance apart as the panel width, less 1/32 or so. Put a strip of
polythene sheet between them to prevent the glue sticking the panel to the
ply/mdf. Glue up the edges of the boards, assemble the panel and put it
between the cleats. If you've got the distance apart correct, the panel
will almost fit between the cleats, but not quite, looking like a very
shallow tent, with the joint at its apex . Put another sheet of of poly
over the top, and weight the whole lot down with sandbags/pile of magazines
etc. The panel will be forced down flat and will bear hard against the
cleats, forcing the joint tightly together and keeping perfect alignment.
This is similar to the method used by some guitar-makers to joint 1/4" stock
for backs and soundboards. It works pretty well for 2 or 3 piece panels,
but might be a bit awkward for a larger number of boards.
You may need to experiment a little with the distances apart, using a dry
Are the edges of the boards precisely square to the faces? If you didn't use a
true precision square to align the fence on your jointer, they might not be.
(Note: if your square doesn't say "Starrett" or "Incra" it might not be as
square as you think.) A slight variations from dead-on-square in the jointer
alignment can be compensated for by jointing the edge of one board with its
top face against the fence, and the mating edge of the next board with its
bottom face against the fence, so that (for example) an 89-degree edge on one
board will mate against a 91-degree edge on the other, still producing a flat
Your clamping pressure may be too high. I've successfully edge-glued 1/2"
stock without any problems -- but never into panels quite that wide.
Are you trying to glue up the entire 20-inch panel at once? That's a lot to
try to do in one shot with stock that thin. It will probably work better if
you glue it up in stages, e.g. glue up two 10-inch panels, wait for the glue
to cure, and then glue them up to make the full width.
Lastly, lay cauls (straight pieces of stout lumber) across the glued-up panel
at each end, and hold them in place with C-clamps. Use waxed paper in between
the cauls and the panel to prevent the cauls becoming attached to the panel.
Hope this helps...
Doug Miller (alphageek at milmac dot com)
How come we choose from just two people to run for president and 50 for Miss America?
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