W CHAN (in Pxlve.2315$mw1.677@trnddc09) said:
| Sorry for the newbie question. I was reading the recent issue of
| Fine Woodworking and it suggested that I use culls in order to
| distribute the pressure when clamping a wide area. This all makes
| sense in theory, but my question is how much of a convex do you
| make? I'm using 1.5"x1.5" lumber at both 24" or 32" in length.
| Would an arc where about 1/4" is taken off each end of the lumber
| bee too much? Or not enough? Also, is this too thick of a piece of
| wood for a clamping cull?
| Sorry for the dumb question, but just trying to get an idea from the
| experienced people on the newgroup. Is it helps, I'm clamping up a
| plywood cabinet that's 26" deep, hence the 32" long clamping cull
| (3" on each end for the clamps to grab onto).
It's not a dumb question - but I think you're trying to make the
problem more difficult than it needs to be.
Instead of depending on the springiness of the caul (which isn't
practical to consider controlling because there are just too many
variables), consider using more clamps. It's almost a given that
there's no such thing as "too many clamps" - but it's more practical
to add clamps than to engineer a non-linear caul for each length you
want to clamp.
I use straight cauls and space clamps anywhere from 3" to 16" apart,
depending on what it is that I'm gluing and what kind of glue.
Keep in mind that clamps aren't terribly difficult to make and that
it's not necessary to rush out and spend big bux to have the clamps
you need. There's a photo of one of my better (simple, inexpensive,
reliable) box clamps at <http://www.iedu.com/DeSoto/drawer_clamp.html
that might provide an idea or two.
DeSoto, Iowa USA