Shelf-Life of regulator rebuild kits

[bl6394]

...
I would assume that means they are EDPM. They have been stored in the dark, away from UV. What would the shelf life of EDPM be?

...

If you look at the link I provided earlier - you'll see that the shelf life of properly stored EDPM o-rings is considered unlimited by the SAE.

 

[KeithG]

The link was for a 1998 spec. It appears some more recent specs (2011) give longer shelf life to some things: Nitrile is now 15 years for the DoD.

Elastomer Shelf Life Recommendation | Aerospace Recommended Practice

 

[redacted]

What do you think would happen if one of those o-rings turned out to be defective?

 

[Rusty Shackleford]

If you look at the link I provided earlier - you'll see that the shelf life of properly stored EDPM o-rings is considered unlimited by the SAE.

Assuming I can verify my 1999-2002 vintage kits are indeed EDPM, then I should be good to go.

Thanks for the link, I did check it, just being extra sure.

 

[bl6394]

The link was for a 1998 spec. It appears some more recent specs (2011) give longer shelf life to some things: Nitrile is now 15 years for the DoD.

Elastomer Shelf Life Recommendation | Aerospace Recommended Practice

In 1998 or 2011 - the proposed shelf life of EDPM is unlimited.

 

[Rusty Shackleford]

What do you think would happen if one of those o-rings turned out to be defective?

I would wager It will either blow when I am pressure testing it after the rebuild or it will start leaking tiny bubbles.

Depending on whether it is a HP O-ring like the Piston Stem or a LP O-Ring somewhere else.

 

[redacted]

The key point is a defective o-ring is not going to suddenly cut off your gas supply.

 

[KeithG]

What do you think would happen if one of those o-rings turned out to be defective?

The same thing as a brand new defective oring?

I (vaguely) remember reading some threads about people swapping out their hoses every few years because they wanted to avoid a failure. I think some of the posters had "new" replacement hoses that failed within a year or so. When questioned about whether the hoses were "new" or "new to them", they were unable to answer. They had no idea how old the "new replacement" parts were. Maybe they were older than the perfectly fine hose they removed?

I guess my (obtuse) point is: If you toss your kit because you have tagged it as "too old", how will you know how old the replacement kit you run out and buy is?

There is lots of NOS out there...

 

[bl6394]

I guess my (obtuse) point is: If you toss your kit because you have tagged it as "too old", how will you know how old the replacement kit you run out and buy is?

There is lots of NOS out there...

My Hollis service kits have a manufactures date on them. The scuba pro kits have a barcode from which SCUBA Pro can determine the date of manufacture.

Some kits are hard to determine.

We rotate stock and make an effort not to over stock kits causing them to sit on the shelf for an extended period of time.

As a former service tech, it seems that the OP understands what he's doing. If he's using this on his own regs I don't see a huge problem.

I would not choose to use 15-year-old kits on regs that I was servicing for other people. Particularly if the manufacturer provided a recommend a shelf life that had been exceeded.

From the point of view of risk mitigation, it would not be prudent.

 

[Couv]

Consider this, Bigfoot-Daisy sells service kits on eBay-some of which are over 20 years old. Do you think the editor of Regulator Savvy and wife of the author would be selling questionable kits?