VIDEOClick to see full answer. Thereof, how tight do compression fittings need to be?Really you should only tighten a compression fitting about 1.25 turns, but I like to do turns in small increments and check for leaks after each turn. You can always tighten a compression fitting more, but you can’t un-tighten a compression fitting.Similarly, which is better solder or compression fitting? Although compression fittings are generally considered more reliable than threaded fittings, there are some potential problems. In general, compression fittings are not as resistant to vibration as soldered or welded fittings. Repeated bending may cause the ferrule to lose its grip on the tube. Subsequently, one may also ask, do you use Teflon tape on compression fittings? The bolts have to be tightened evenly. Thread sealants such as joint compound (pipe dope or thread seal tape such as PTFE tape) are unnecessary on compression fitting threads, as it is not the thread that seals the joint but rather the compression of the ferrule between the nut and pipe.Can I use compression fittings on fuel line?Double flare tubing compression fittings are safe to use on fuel and hydraulic lines. Always check with a fluid power engineer for fitting recommendations on high pressure (>2000PSI) hydraulic systems. Fittings for pressures up to 3000PSI are fairly standard.