How to Measure O-Rings

Factors to Consider When Picking O-rings They include but are not limited to operating conditions, chemical compatibility, sealing pressure, temperature, durometer, size, and cost. Depending on the specific situation, you may also look at abrasion, tear, ozone, electrical resistance properties.

What is the Best O-Ring Material For the Application?

• Nitrile (Buna-N) is a general purpose material suited for petroleum oils, water, and some hydraulic fluids.
• Ethylene Propylene Rubber (EPR) operates in a temperature range between -60 degrees Fahrenheit to 250 degrees Fahrenheit.

Viton™ is a fluoropolymer elastomer and synthetic rubber compound, trademarked by DuPont under this brand name. It’s a fluorinated hydrocarbon rubber product with amazing capabilities, designed to withstand even the most challenging of environments.

Temperature: Viton® seals can withstand temperatures up between -20°C to 210°C. This makes Viton® far superior to Nitrile in these regards. They are also designed to resist most oils and lubricants, more importantly petroleum-based lubricants.

1. Place the O-ring on a clean, flat, level surface.
2. Determine the inside diameter by using a ruler to measure from one inner edge to another.
3. Use a ruler to measure the diameter, from one outer corner of the O-ring to the other outer corner.
4. Finally, measure the cross-section.

it’s one of the most highly used seal materials in the oil and gas industry.as long as your o-ring is the correct size,buna-n should hold up just fine to regular diesel fuel.

Viton® Material Description Viton® is a trade name for the Chemours brand of fluorocarbon, also known as FKM. FKM is a well-known high-performance rubber that has excellent resistance to high temperature, ozone, weather, oxygen, mineral oil, fuels, hydraulic fluids, aromatics and many organic solvents and chemicals.

synthetic rubber
What is FKM? FKM is the ASTM designation for a class of fluorinated, carbon-based synthetic rubber, commonly known as fluoroelastomer. FKM has impressive heat resistance, allowing FKM seals to withstand temperatures greater than 200°C.

Neoprene offers moderate resistance to oils and petroleum products, but provides significantly greater resistance to sunlight, ozone, and weather….What’s the Difference Between Nitrile vs. Neoprene?

Nitrile rubber
Nitrile rubber — also known as acrylonitrile butadiene rubber, NBR, or Buna-N — is a synthetically produced, petroleum-based rubber ideal for seals, gaskets and o-rings. Nitrile is a highly versatile rubber. It is used in countless applications and products, from marine fuel systems to small engine carburetors.

The standard sizes used by Parco and the other major O-ring manufacturers in the United States are defined by Aerospace Standard AS568. There are 369 standard sizes of O-rings with inside diameters ranging from 0.029 to 25.940 inches and cross sections ranging from 0.040 to 0.275 inch.

Generally, the purpose of O-Rings is to block a pathway that fluid or air may escape through, as it is a sealing device.

The correct o ring size is 3/8″ o.d. (outside diameter) and 1/4″ i.d. (inside diameter)

An o ring will sit in the middle of a gland when it’s at rest, but as pressure begins to rise in the sealing system, the O-ring shifts to the opposite side of the pressure.