Tank O-Ring size????

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Cave Diver once bubbled...
Fred,

Since are knowledgeable about o-rings, how about shedding some light on automotive applications.

Specifically, are there any differences in the green o-rings readily available in bulk for use in automotive air conditioning applications and the green o-rings used in SCUBA gear?

Also, what are the differences between O-ring types? (HBNR, Viton, etc.)

Refigerant rings are HYDROGENATED NITRILE (HNBR, HSN)
Hydrogenated nitrile was developed as an air-resistant variant of nitrile rubber. In HNBR,the carbon-carbon double bonds in the main polymer chain are saturated with hydrogen atoms in a process called “hydrogenation” that improves the material’s thermal stability and oxidation resistance. Flash color on several of these ring compounds are green.


Vitons are FLUOROCARBON (FKM, FPM) Fluorocarbon (FKM) has excellent resistance to high temperatures and a broad range of
chemicals. Permeability and compression set are excellent. Polymer is sold under the tradenames Viton®, Dyneon™, and others.

(descriptions from Parker)

As for the colored rings in the reg kits, any ring material can be had with almost any color coumpounded into it on a special order run of a few thousand rings, or rings can be colored in an aftermolding process. I expect very few "flash colored" rings in regulator part kits are special materials or durometer. I expect that most of the flash colors are to keep ham handed repair techs from installing kit rings in the wrong place. The Scubapro MK V uses almost all ring sizes from 10 thru 17, and several are easy to mis-install. Flash colors based on ring SIZE will help minimally trained techs to assemble a rig without mistakes.

As far as regulator assembly goes, I have found very few places where an 70 or 90 duro viton ring won't work and resist extrusion, but I haven't worked much on the "new" SP line yet. I have yet to find a piston first stage regulator that performs much better than the MKV in warm water. The primary "improvement" in the later versions of SP piston regs is the fact that SP still has a vaild patent on those.

FT
 
568 refers to the Aerospace 568a seal specifications standards which is more about geometric seal tolerances than anything else. The 214 is the seal size which specifies the cross sectional diameter as well as the ID of the seal.

If the seal is white I would say it likely is a FKM (Viton) product.
 
you can buy cheap O-rings in all kind of sizes (Buna-N or Viton or Silicone rubber) from Small Parts.
www.smallparts.com
check pages 142-144 in their catalogue (PDF format).
They don't come in color variations, just black. You can also get O-rings in metric sizes.
 
I would only use Parker O-Rings, but I'm biased, I work for them :D
 
It may be a 4 year old question but I needed the answer today, I'm making my own save-a-dive kit...
 
It may be a 4 year old question but I needed the answer today, I'm making my own save-a-dive kit...
 
awesome...thanks all for the info. This will save me a few bucks.
 
https://www.shearwater.com/products/swift/

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