O-Ring Sizes And Uses
The Reef Scuba list has a couple of oopses part number wise, although what they call out is close to the correct size and may work fine. The most notable oops are the hose rings. I believe the DIN should take a metric series ring, but I dont have the cross over # since I dont use them. This is what I stock in my save a dive kit. The complete Parker O-ring part number is the size shown below plus a compound number to specify material. I tend to buy all them in Viton, but the Buna-N is a bit cheaper. Please remember that Viton rings simply don't go bad from age if kept in a sealed UV opaque container. Normal shelf life for Viton rings is 20 years. Small prescription medicine bottles work well as do flip top canisters and zip lock bags if the zip locks are stored in a closet or other opaque container/box. Pricing for commercial rings quantities is such that you can often get 25 or 50 rings of each size for very nearly the bottom line price as 10. Talk to buddies and work up a list, then everyone can fill their kit as needed. Any O-ring dealer can cross reference a Parker size number and most have a compound cross over list as well.
Buna-N has a compound suffix of N674-70.
Brown Viton has a compound suffix of V884-75 for 75 Duro rings or V894-90 for 90 Duro rings. Use harder rings where gaps are big, like on tank yoke O-rings. An EPR pr polyurethane ring seems to be good for tanks vales that seem to just eat rings. The suffix for EPR is E893-80. For the polyurethane ring (the white ones from Sherwood) P642-70. The following is the proper ring sizes and where I use them if it's a common part . Any ring that MAY see pure O2 above about 100 psi needs to be Viton.
2-002 SPG gauge swivel spindle
2-003 Various switch seals
2-006 Various switch seals
2-007 Various switch seals
2-008 Various switch seals
2-010 Piston HP ring for SP MK V and clones. Valve spindle seal, and a bunch of other places on all kinds of gear.
2-011 Internals of MK V and second stages
2-012 Internals of MK V and second stages
2-013 Internals of MK V and second stages
2-014 Tank K-valve "skinny" ring, Valve handle spindle seal
2-015 Internals of MK V, clones and second stages
2-016 Internals of MK V, clones and second stages
2-017 Internals of MK V, clones and second stages
2-018 Internals of MK V, clones and second stages
2-019 Internals of MK V, clones and second stages
2-020 Internals of second stage and some later SP firsts
2-021 Internals of second stage and some later SP firsts
2-022 Internals of MK V and clones Main piston O-ring (major wear item!)
2-111 Tank K-valve "Fat" ring
2-214 3/4"NPSM tank valve seal
3-902 5/16" (not used in Scuba much, can be found on Pneumatic submersible tools)
3-903 3/8" hose port, Normal LP hose
3-904 7/16" hose port, Normal HP port
3-905 1/2" hose port. Oversize LP hose used by Dacor and a few others.