I recently installed a new hot water heater and replaced the copper flexible hot & cold lines with steel braided lines that use compression fittings on the 3/4″ copper supply lines. What causes new compression fittings to leak. Am I doing something wrong? (i.e. not cutting the tube at a perfect 90 degree angle and deburring it enough?) I am afraid of tightening the joint any further. Any solutions would be greatly appreciated.