Making proper gas tight connections

I recently worked on a system that even being silver soldered had developed leaks. The reason this occurred is that loads on the tubing was being taken by the soldered joints not the parent tubing.  
When I build a system all the joints in the tubing are sleeved to achieve a sliding fit. I even built my own special tool to roll a few 1000's of an inch off the tubing diameter. This means that the brazing or soldering is not taking the loads and vibration. It basically just seals the joint to make a gas tight connection. 

Beware of steel condensers! The Mexicolder systems use copper condensers which cost more but will save you hassle in the long term.