Dumb Question About O Rings

[Sasquatch]

Wow...if I only knew somebody in the biz! Hmmmmmmmmm

:d

 

[wilkie]

Is there more than one size for std. J/K valves ? I got curious and had a look in my "save-a-dive" kit, now my kit has expanded steadily since it's humble beginnings, and now contains a plethora of 0-rings, the smallist to fit a SPG spindle, the largest to fit a 3/4" K valve/tank.

Now for the question, amoung this flock I see at least 3 different sizes that I would - on site - guess to be tank valve/yoke size.....

I got some: 1/2 x 11/16 = (AS568A-)112, 17/32 x 11/16 = (#)015, 1/2 x 5/8 = (#) 014 So I went to the basement to have a look, and all of my tanks (4) take the 112, but it seems I recall using the 015, on rental tanks,and i'm pretty sure that Ive seen the 014 on a tank valve. (I have a pretty good eye for measurements of less than an inch, iow-I know what .0020" "looks" like)

So does anybody know, off the top, what # 0-ring, or 0-rings we should pack around?

 

[wilkie]

Another ? : what material/durometer, most of the 0-rings that I have appear to be "good-ole" buna N = 70 durometer (standard stuff), but I also have a previously opake (now amber)014 ring.

I understand ,from this thread, that purple = EPDM, I think that green = viton, black = buna N,But, is there more than one durometer rating for these matterials ?, what is the opake...teflon/silicone??? It feels too sturdy for silicone, but it has taken on the amber colour that silicone is famous for????

Can someone wise me up?

 

[wilkie]

Bump

 

[captain]

Color is not an indication of material. The regulator manufactures may have them made in colors to help identify two of the same size but different material used in different locationsto help in assembly. Most materials can be had in any number of colors.

 

[bugsmashers]

Some time ago I bought 100 pieces of each size of viton O-ring used in my scuba equipment from Mcmaster-Carr, for the price of about 3 from my LDS. These are 100% O2 compatible and are the same as what the LDS will sell, ther is no "Scuba" quality O-ring. The dive industry is just trying to make some money off of people who aren't willing to do the legwork.

 

[Web Monkey]

being a Parker Hannifin employee and stock holder I would highly reccommend to buy the best O-Rings, Parker O-rings
http://www.parker.com/ead/cm2.asp?cmid=3106

It's a nice site, and they're nice o-rings, but I don't think they're really looking to ship out a bag of 10.

Terry

 

[Ed Palma]

Some time ago I bought 100 pieces of each size of viton O-ring used in my scuba equipment from Mcmaster-Carr, for the price of about 3 from my LDS. These are 100% O2 compatible and are the same as what the LDS will sell, ther is no "Scuba" quality O-ring. The dive industry is just trying to make some money off of people who aren't willing to do the legwork.

So, am I correct in assuming that as long as they have the same durometer rating and are of similar size and shape, then an o-ring by any other manufacturer (other than scuba) will work just as well? Do equipment manufacturers make their own o-rings to spec or do they just order from the same folks who provided rings to hardware stores?

 

[captain]

When any device not just scuba equiptment is engineered in most cases it is engineered to be able to use commonly avaiable off the shelf bearings, seals, O rings, etc. This saves on manufacturing cost. Other than highly specialized designes such as maybe spacecraft will specially made sizes be used.

 

[pescador775]

I didn't know that some people thought that a "SCUBA" O ring was different from a "regular" O ring. It explains the bashing of "hardware" and other open source O rings. After all these years, Scuba board is still interesting, one urban legend after another. It is true that some SCUBA regulators like Scubapro specify a particular O ring compound and hardness for the piston or some other part which may not be easy to find except in a black market kit. If the specs of the "special" rings were made public they would be relatively easy to find. That's another story.