Hi, Dee.  Craig here.  Neener neener to the single clamp on glued joints,
but ok on the balanced 4 clamps of Ampico blocks.  Nothing at all wrong
with that!

   For the other readers: Clamps tend to slide parts when used without
restraints, and to imagine the detailed work required to restrain a
hundred small parts while clamping them is beyond my imagination.

   I suggest weighting small parts, such as pneumatics, with 1-2#
blocks of lead weight.  If you are suggesting that rubber bands should
never be used to clamp very small stuff like valve blocks, then perhaps
you will also tell us why.  Don't worry.  I will be appropriately
ashamed of myself.

   The reason I suggest weights for most things is because the force
applied by a weight is vertical and cannot slide the parts insiduously.
You don't have to watch to see which way it is going to take off and
skid on you.  Not so with single spring clamps (if that is what someone
may assume).  A single spring clamp has gravity pulling down on its
handles for one thing, so it tends to have a component of force
tangential to the surface you are trying to glue.  Sorry, but it's a
fact of life.  Just using a little trig will show you that you have
vectors in two directions, one of which will slide the joint, whereas
with weight (or a rubber band circle), you have a single vector normal
to the gluing surface.

   Now, suppose you make it a point to keep the clamp handles
vertical...  No more gravity, but instead, you have the almost
impossible requirement (with a single clamp) to keep the contact points
of the jaws perfectly aligned on  a plane normal (perpendicular) to the
gluing surface.  Otherwise, they will still have a sliding component.
Some people are very adept at positioning spring clamps and never have
any trouble.  On the other hand, some of us on occassion discover too
late that they are not as experienced, and end up breaking the joint
and redoing it.

   I can't fault anyone who successfully uses clamps, but I sure can
warn anybody who imagines themselves to be as good as you are, to learn
the trick first.

Craig B.