How safe are o-rings as seals?
O-rings have been used in the pneumatic and hydraulic industries for many decades. The pistons that lift the bed of a dump truck are sealed with o-rings and develop pressures of 30,000 pounds per square inch, far more than we see in underwater housings. The key is proper design, smoothness, and maintenance of the groove or other mating surface. O-rings rarely fail; most leaks in housings are caused by failure of the user to keep the o-rings clean and free of particles that can allow water to seep past the seal.
