Originally Posted by
Steve Schoene
The manufacturers have been calling for similar clamp pressures for a long time, and it's certainly not in their interests to tell you to do something that weakens the bond. So why haven't all of Norm's, "don't squeeze out all the glue" joints not failed? Because in most cases edge joints have enough strength to perform satisfactorily even if they don't have maximum strength. But since clamping more firmly has such little cost it doesn't pay not to go for stronger.
But the story that also needs telling is how to get a joint suitably prepared for gluing. Again, lots of less than perfectly fitted joints will hold up OK because of the "safety factor" built in, but to get a joint where there is NO visible glue line is a different question. By no line I mean that you can only tell the wood is joined when several grain lines all stop at the same plane under close inspection. That's not what you get directly off the saw, or with a quick pass on the jointer except in the rarest of cases.