Viton® Oxygen-Compatible O-Rings

Dive Gear Express stocks a variety of DuPont Performance Elastomers Viton® brand O-rings
suitable for use in SCUBA applications.

Materials -- O-rings can be made of a very long list of exotic materials; most are inappropriate for SCUBA applications. The materials commonly used in SCUBA applications appear in the following table.

Viton Brand FKM -- Viton is DuPont Performance Elastomer's brand name for fluorocarbon based elastomers (FKM). The Viton O-rings sold at Dive Gear Express are 100% virgin Viton family type "A." However, DuPont Performance Elastomers is not the only company that manufactures FKM products. Bear in mind that not all FKMs are equivalent, and there are even different types of Viton O-rings intended for various different applications. Many people incorrectly refer to any and all FKM O-rings or even generic "oxygen-compatible" O-rings as Viton. As a result, you could end up with O-rings that are not the type of Viton you need, let alone a Viton O-ring at all. Products not made from Viton may fall short of the expected performance.

Hardness -- O-rings are normally available with a hardness rating, as measured by an ASTM type-A durometer, of 70 (the "soft" kind) or more rarely a rating of 90 (the "stiff" kind). The O-rings sold on this page are 90-duro (except for the -003 SPG O-ring), and well suited for the SCUBA applications we describe. The soft O-rings are appropriate for dynamic applications where the O-ring is providing a seal with a constantly moving part, such as inside regulators. The stiff O-rings are more durable in static applications where the O-ring is providing a seal with stationary or occasionally moving parts, such as a valve.

Color -- O-rings are available in nearly any color, although most commonly seen in black. The Viton O-rings sold on this page are brown, simply to make them easily distinguishable from Nitrile O-rings which are usually black and EPDM O-rings which are often purple. Some people believe there is a difference in quality based on color, but that is more likely attributed to unknowingly using soft dynamic O-rings in static applications. Our O-ring manufacturer states there is little difference in quality for O-rings based on color alone, and independent testing supports that statement. Some people also incorrectly believe a Viton O-ring can be distinguished from a Nitrile O-ring by the surface appearance. Nitrile O-rings are said to have a shiny surface, and Viton O-rings are said to have a matte surface. This is not a reliable indicator, and certainly not true if the O-ring has been lubricated.

OEM-Supplied O-Rings -- Designers of SCUBA equipment often specify O-rings with special properties and materials for specific uses inside their equipment, particularly regulator internal o-rings. Substituting any other O-ring just because it's the right size can cause difficult-to-diagnose problems and degrade performance.

Tribolube® Oxygen-Compatible Lubricant

Aerospace Lubricants is proud to offer their latest Tribolube® line of products designed specifically for scuba diving applications. With over 35 years of background science, the Tribolube® line of products offers superior extreme pressure and anti-wear properties, thus extending equipment life by dramatically reducing corrosion and residue buildup. An oxygen compatible lubricant is often specified where oxygen compatibility is required in dynamic O-ring lubrication; however, this lubricant actually works better than silicone grease (which is not oxygen-compatible) for nearly every type of SCUBA application. Tribolube® 71 is designed for open and closed circuit diving systems. This O2 safe lubricant is compatible with all o-rings and materials used in the scuba industry, and is available in a choice of three application sizes, a 2-ounce tube or syringe as well as a 5 gram single use pak. Tribolube® KO2 solvent cleaner is designed for the removal of PFPE lubricants used in open and closed circuit diving systems and is available in an 8-ounce spray bottle.

Tek Tip

How Much and Where to Use Lubricant Some people very sparingly lubricate the SPG swivel O-ring. Some people also sparingly lubricate the threads of valves before they are installed in the cylinder neck. Do NOT lubricate the neck O-ring itself, and absolutely positively do not lubricate the valve/regulator seal O-ring or DIN threads. Most lubricant is used with dynamic seals in regulators and valves. As a general rule, the O-rings used with static seals in SCUBA applications should not be lubricated at all. The lubricant just causes contamination to stick to the surface of the O-ring and results in more problems with a static seal than any dubious benefit the lubricant might provide.

This three piece brass o-ring pick set is specifically designed for removal and placement of o-rings, but at Dive Gear Express we use them for all sorts of other tasks. The brass tips won't scratch soft seating surfaces in valves, regulators or other equipment and the color coded plastic handles have a comfortable ridged grip. Two of the tools have a sharp point and work well for removal, the third has a tiny ball on the end and is nice for placement. The set of three tools are in a re-sealable plastic package to help keep them organized and clean.