[gone_fishin]

Originally posted by unregistered
I'm guessing that if myv65 can mention Roark, anything goes !
(an ind std ref BTW, a good read but tough sledding for the untutored)

after designing and doing failure analysis of o-ring joints for many years (in both static and cyclic pressure service),
there are several useful guidlines:
- when the component surfaces make contact, as they must, there should be 30 to 40% compression of the crossection
- the o-ring's volume should be between 60 and 70% of the groove's
- using a 30 to 50 Shore A durometer (hardness) material will make the surface finish less critical
- the o-ring's (centerline) length should match the groove's (do NOT stretch)
- the groove must have an outer containment ring to 'capture' the o-ring, else it is functioning as a gasket (different design basis)

do not use a sealant with the o-ring (no need if properly designed, will overfill the groove, make disassembly a pain, etc)

g_f
o-rings, properly designed, are FAR more reliable than gaskets

Hmm.. I won't argue with you there but the task at hand in Cathar's block is critical. The design is based on forced water through the slot and a potential loss of presure from user ignorance is a likely scenario.