Goo (the scientific term) whether it be "krystolube", "torrseal", "gloop" or any of the many silicone based products, will NOT fill a void caused by cracked or scratched O-Rings, pitted, gouged, rusty, flaking, porous or cracked sealing surfaces. They can (and will) increase the sealing ability of any O-Ring interface, by lubricating and covering microscopic imperfections. In other words, they can only work on smooth CLEAN surfaces. Use your elbow grease first (BUT USE NO_NO_NO petroleum solvents- just alcohol, and dry thoroughly), then any other grease/sealant that is appropriate for the gas you are using. Less is better, and the O-Ring should barely glisten. Excess grease will attract and retain dirt, and dirt will ruin seals. Viton O-Rings are great, but unless you plan on not having your equipment serviced yearly, there is little that a higher Oxy content will do to most modern day O-Rings in that short amount of time. We only used viton in Chlorine, Flourine, and other caustic environments.
BTW, this comes from TOO many hours in cryogenic research labs determining the nominal spectra of various compounds and isotopes of Hydrogen. Mois was not the scientist, but the "plumber" (aka Lab Technician, and Lab Machinist; also affectionately called "Mr Makeitwork", "McGuyver", "hey you" and "G*D DAMMIT"). Some one pass me the sill torr and the sniffer... I got a 10-3 torr leak in this manifold...
:tease: