Just received my fww tools and shops issue.
Was anyone else surprised that there were no reader letters regarding the
article generally judged to be the worst in recent memory (the clamp and
glue "the science is way over your head so just trust me on it" article)?
Given the amout and type of reaction it got here and in other forums, I was
very surprised. Maybe next month.
But it wasn't really dumb. From the articles he's published elsewhere
it looks like for maximum strength you need clamping pressure that is a
particular fraction of the crush strength of the wood.
Given that hard maple has a high crush strength, this means that max
glue bond requires very high clamping force.
Of course, the article fails to cover the minimum clamping force to
achieve *reasonable* bond strengths, which is all that most woodworkers
will ever need.
Note that Franklin recommends up to 250psi for hardwoods with titebond
III. For a 1" thick by 5" long panel glue up, this would mean fifteen
thousand pounds of force. 7.5 tons!
That's roughly 14 Bessey K-bodies, a dozen Jorgensen heavy-duty
F-clamps, or at least three heavy-duty steel I-beam clamps.
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