Gotcha...
I'm in favor of keeping the tubing as straight as possible, and "tug free", which can tilt a block off the core.
Here's pHaestus' article on the subject:
http://www.procooling.com/articles/h...s_with_h2o.php
In short, avoid mitre elbows, and if possible, go with two 45 deg copper sweeps. That's what I plan to use in my rig, for every significant turn of the tubing, with clamps, of course!