Jeff,
This probably goes without saying, but I have to ask anyway. I'm assuming you put beads on all of the radiator connections? Commercial radiators normally come with beaded fittings. I'm more curious about the sweep L's and other pieces of tubing in your system. I am aware of at least one rotary a/c that made an emergency landing after having a hose blow off in flight. If not, Earl's Supply sells beading tools that do a pretty fair job for the price.
Mark