"Garry Collins" wrote in message
...
I am just getting into edge gluing to make wide boards, say around 18
inches. Each time that I try the finished board seems to warp across the
board. I am positive that the board was flat in the clamp and stayed
there
for a few days.

Should I use several narrow boards or a couple of wider boards? Is the end
grain at the end of the boards important?

Several responses, some good advice. Above all, have your wood acclimated.
Could be a couple of weeks, could be more, depending on the source and
storage of the wood. Construction grade with high turnover may have to shed
10% to get in line with indoor conditions, because it leaves the mill at
~20% moisture content. That's a couple months. Second, get edges at 90
degrees before you draw the clamps. Don't have to be anal about it, you can
set the jointer fence at a clean angle, or you can do the flippity flip. I
figure that fence is better at holding 90 than I am, so I take what it
gives.

Then there's the "smiles" controversy. I think its a pretense. I get the
boards arrayed to look the best and glue 'em. Years in dad's shop, my shop,
school shop seem to show that it really doesn't make much difference as long
as you don't try to join the first board away from the heart to others of
its ring curvature.

What can make a huge difference is the way you use the clamps. You want
center of the screw aligned with center of the board with pipe or bar types,
and there are few who take the time. Can screw things up real fast if you
don't draw straight through the center, but toward an edge. I use some of
my handy shims to elevate the glueup and make it so. The Besseys are a good
thing to have, but I still alternate. Lay a board across the glueup to
check for flat, even if you're not using cauls.