Dumb Question About O Rings

[Sasquatch]

This is kinda embarrassing but I've done a search and couldn't find the answer. OK, here goes.

Why are tank O rings two bucks a piece at the LDS? Are they special SCUBA O rings? My guess is they aren't special so if I went to my hardware store could I pick up an O ring for, like, 50 cents?

(Not the tank body O ring but the little one that the first stage seats in)

Thanks!

Dave

 

[Packhorse]

O2/nitrox ready maybe?

 

[Sasquatch]

Geez, good point...but welding rigs and other industrial gas containers would be under the same umbrella. And they probably are...but do they use special O rings? Not that I recall.

 

[Packhorse]

O2 tanks yes other gases probably not.
My LDS charges $1 per O ring and that is NZ$1 so US65 cents.
O2 ready O rings are probably more.
If your LDS is charging $2 they are probably trying to make up for all the money they loose on air fills.

 

[Azza]

O2 tanks yes other gases probably not.
My LDS charges $1 per O ring and that is NZ$1 so US65 cents.
O2 ready O rings are probably more.
If your LDS is charging $2 they are probably trying to make up for all the money they loose on air fills.

Go to Blackwood Paykels. They sell em for around 4c each. No need to pay a dollar.
Any engineering shop should have them cheap as chips.

 

[300bar]

2$ for 1 O-ring your LDS is meking his fortune on O-rings.

But yes there is a difference between scuba O-rings and those
from the hardware store.
Scuba O-rings are much stronger.Try the soft hardware ones and
you will see they won't last very long.Most will go with a bang on
the first use

 

[Mako Mark]

just make sure you know what you are buying

but yes they cost a couple of cents each and the dive stores sell them for much much more.

 

[Luis H]

From McMaster-Carr you can buy Buna-N (nitrile) O-rings (with a Durometer of A70) in a bag of 100 for $2.89. Buna-N O-rings is the most common O-ring for air service.

They also have the same size O-rings in Viton, Silicon, and EPDM ($10.06 for 100, $10.27 for 100, and $7.53 for 100, respectively). I can’t remember what is recommended for O2 service.

The Durometer on all the above mention O-rings is A70 except for Viton is A75.

I am not positive, but I believe that my local hardware store carries Buna-N, A70 Durometer O-rings (the same as my LDS).


But, I agree with Cancun Mark, you need to make sure you know what you are buying.

 

[Leadking]

What kind of o-rings? Viton, polyurethane, EPDM, Buna-N? What Durometer?

Yes o-rings at a dive store are more expensive than a bulk purchase at an o-ring supplier. Same is true when you want one screw at a hardware store. Keeping inventory, answering questions, having a RETAIL storefront, liability insurance-these things add up. A dive store does some things at below cost and need to make it up elsewhere. It is a blend of margins, some low and some high that allows a full service dive store to exist. Take away the extra $1.50 here and it will have to go somewhere else. My two cents worth.

Lee
www.seapearls.com

P.S. I cannot buy quality o-rings for four cents each and I buy thousands.
As a safety note Thermo valves require 90 durometer.

 

[pescador775]

Generally, the hardware store, soft, 70 duro, O rings are fine for SCUBA, except for oxygen service. Personally, I would use a 90 duro for the face ring on the valve. These hard O rings are not more expensive but may be harder to find. The pricing on O rings is peculiar and price gouging on small lots is common. A common Buna N, Nitrile O ring is probably worth about a nickel at retail, viton a few cents more.