How long do service kits last?

[Eric Sedletzky]

Question.
How long do 1st and second stage service kits last on the shelf?
I know that with certain auto parts rebuild kits of various types, rubber components can begin to degrade and other gaskets etc. can lose their integrity over time.
I’m just wondering about regulator service kits if anyone has come across an original old stock kit that has deteriorated beyond usefulness just sitting in the package.
I have an Aqualung 900001 kit for a Conshelf that has a born-on date from last year. So this got me thinking that maybe Aqualung puts those on because they have a time limit for using them.
This also got me thinking that just because a kit was installed into a reg but the reg was not used much for many years may not mean that the kit is still good inside.
Is there such a thing as a “fresh” kit, and an “expired” kit?
Any thoughts?

 

[GJC]

Depends on the type of rubber the o rings are made from. I think most are epdm or viton, so unlimited. There may be some that have some buna but I not certain about that.

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[Bigbella]

It certainly varies, based upon materials, and storage methods; though, I would actively avoid those transitioning from vintage to antique — but those Cyklon diaphragms from 2004 and the Triton silicone versions from circa 2000, remain perfectly intact.

I'll just keep that 1976 Cyklon service kit around as a souvenir . . .

 

[emoreira]

BUNA-N o-ring has a shelf life of, at least, 15 years. Poliuretante o-rings only 5 years. As mentioned, EPDM and VITON o-rings have unlimited shelf life. Service kits also include metal and plastic parts, where shelf life should be even longer, so a service kit with a few years is perfectly in pristine condition, at least to time degradation.
For further reading you can see SAE ARP-5316 dated 1998