"Lee, Jonathan" <Jonathan.Lee@h...> said:

> I'm planning on building a few torsion boxes for shelving.  They will be
> just longer that 6 feet.  My quandry is how many clamps I need to glue the 1
> ft x 6 ft quarter inch plywood to the torsion box frame.  My golden rule of
> clamping always seems to be that for any clamping job I need at least one
> more clamp than I have ;-) but there must be a better way to estimate
> clamping needs.
>
> If I know the gluing surface area, is there a numerical estimate of how much
> force (in pounds I guess) I need to apply? How much force does a really
> tight Pony clamp exert?

Jonathan, you don't need to worry about the amount of force, you need to
worry about how it's spread.  You can think of each clamp's force spreading
at 45 degree angles from the clamp head.   The farther the clamp head is from
the glue line, the wider the area of coverage of that clamp.  This is one of
the reason that clamping cauls are used.

Stack some wood on top of the 1/4 inch plywood before clamping, and you'll
greatly cut down on the number of clamps needed.

-----------------------------
Hal Laurent, Baltimore MD, US
laurent@c...