O-Rings
Additional Information
There are several different standards to choose from when it comes to O-ring dimensions. The most popular in the United States is the AS568 standard for O-ring sizes and tolerances. Maintained by the Society of Automotive Engineers, this standard allows the user to choose from five different cross-sections with inside diameters ranging from 1/32" to 26". Tube fitting boss seals are included in AS568 as 900 series O-ring sizes, and are intended for use in MS33649 (now superseded by SAE-AS5202) straight thread tube fitings. RT/Dygert also offers a wide array of metric sizes, in both standard and non-standard dimensions. As a subset of the metric sizes offered, we also stock many Japanese Industrial Standard (JIS B2401) sizes. If an O-ring with special size or fluid resistance is required, RT/Dygert can provide custom O-rings, specially made to your demanding requirements.
SIZES
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| AS568A | 908 | |
| Dash No. | 8 | |
| US | Nominal | |
| I.D. | .644" ± .009" | |
| O.D. | .000" | |
| C/S | .087" ± .003" | |
| Volume | .014in3 | |
Gland Charts
MATERIALS
Ethylene Acrylic Rubber
Non-Stock Material
Other Designations
Vamac® (duPont); AEM
Composition
Medium density copolymer of ethylene and methyl acrylate. May also contain a small amount of a third monomer containing carboxylated acid to provide active cure sites in the polymer chain.
Temperature Range
-30 to 350 °F
Description
Ethylene Acrylic, or AEM, rubber is generally used in applications requiring a tough rubber that combines good oil resistance, with heat resistance greater than nitrile or chloroprene at a cost well below that of silicone or fluorocarbon rubbers. Good low temperature properties are imparted by the ethylene content, while the acrylate provides a considerable degree of oil resistance. Ethylene Acrylic rubber is highly saturated, and as a result exhibits excellent resistance to ozone and weathering. Ethylene Acrylic compounds are well suited for applications requiring continuous exposure to hot (170°C) aliphatic hydrocarbons, including most common automotive lubricants and hydraulic fluids. Water and ethylene glycol resistance is good, but softening can occur after long term exposure above 100°C. AEM's good dampening characteristics make it well suited for vibration mounts, pads, and isolators.
Information above applies to the generic material. Specific compounds may exhibit different properties.
Physical Properties*
| Excellent | Good | Fair | Poor | |
| Abrasion resistance | • | |||
| Compression Set | • | |||
| Elongation | • | |||
| Flame resistance | • | |||
| Gas permeability | • | |||
| Low temperature flexibility | • | |||
| Tear resistance | • | |||
| Tensile strength | • |
Chemical Resistance*
| Excellent | Good | Fair | Poor | |
| Automatic transmission fluid | • | |||
| Dilute acids | • | |||
| Dilute alkalis | • | |||
| Ozone | • | |||
| Petroleum oils and fuels | • | |||
| Steam | • | |||
| Water | • | |||
| Weather | • |
*Excellent, good, fair and poor are intended to serve as general guidelines only. Actual testing in the application environment is always recommended.
Information above applies to the generic material. Specific compounds may exhibit different properties.