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O-Rings

O-Rings are available in five different polymer materials as well as Gold and Platinum from Scientific Instrument Services.

O-Rings By Instrument Manufacturer

Viton®
O-Rings are available in five different materials from Scientific Instrument Services.
Buna-N
O-Rings are available in five different materials from Scientific Instrument Services.
Silicone
O-Rings are available in five different materials from Scientific Instrument Services.
PTFE
PTFE is a popular o-ring which is white in color. The PTFE o-rings are popular for use in applications which require a chemically resistant and non-compressible material.
Kalrez®
O-Rings are available in five different materials from Scientific Instrument Services.
Gold, Platinum, Silver/Tin
Pure gold (99.99%) and pure platinum (99.99%) wire ring vacuum gaskets can be constructed from four diameters of wire; i.e. 0.020", 0.025", 0.031", and 0.040" diameters.
Metric O-Rings
Hardness range is 70 to 80 Shore A durometer.
O-Ring Kits
This convenient o-ring kit contains 30 of the most popular sizes, for a total of 380 o-rings, in one convenient kit.
Metric O-Ring Kits
This convenient O-Ring kit contains 36 of the most popular sizes, for a total of 5000 O-Rings, in one convenient kit.
Viton, PTFE and Silicone Sheet Material
These sheets are particularly well suited for cutting your own gaskets and seals.

Comparison

Comparison of O Materials Used in the Construction of O-Rings

Each type has its advantages and disadvantages as listed in the chart below, and the type required depends on the O-Ring application. Of the various types of O-Rings available from SIS, Viton® is the most popular for mass spectrometers and other laboratory instruments. This is due to Viton®'s high temperature stability and good resistance to chemicals and ozone. Gold gaskets are used to make high vacuum and high temperature seals on vacuum flanges.

Property	Buna-N	Viton®	Silicone	PTFE	Kalrez®
Part No. Prefix	B-	V-	S-	T-	K-
Tear Resistance	Good	Good	Poor	Excellent	Good
Abrasive Resistance	Good	Good	Poor	Excellent	Good
Ozone Resistance	Poor	Excellent	Excellent	Good	Excellent
Weather Resistance	Fair	Excellent	Excellent	Good	Excellent
Heat Resistance	Fair	Excellent	Excellent	Good	Excellent
Chemical Resistance	Fair	Excellent	Good	Excellent	Excellent
Oil Resistance	Poor	Excellent	Poor	Good	Excellent
Acid Resistance	Fair	Excellent	Good	Excellent	Excellent
Alkali Resistance	Good	Good	Fair	Excellent	Excellent
Steam Resistance	Fair	Fair	Poor	Good	Excellent
Minimum Usable Temp	-65 deg F -54 deg C	-65 deg F -54 deg C	-120 deg F -85 Deg C	-110 deg F -79 deg C	-35 deg F -37 deg C
Maximum Usable Temp	300 deg F 150 deg C	500 deg F 260 deg C	450 deg F 232 deg C	500 deg F 260 deg C	550 deg F 288 deg C
Color	Black	Black	Red	White	Black
Impermeability	Fair	Good	Poor	Excellent	Good
Tensile Strength	Good	Good	Poor	Excellent	Good

Kalrez® and Viton® are registered trademarks of E. I. DuPont de Nemours

Sizes

O-Ring Dimension and Availability Charts

O-Rings are available in sizes (sizes 0, 1, 2 and 3) which correspond to the diameter of the cross section of the O-Ring. Within these groups the O-Rings are classified according to their inside diameter. In addition O-Ring Kits of the most popular sizes of O-Rings are available in both Buna and Viton®. If the size you require is not listed, it may still be available. Contact us with your requirements.

Industry Sizes	Cross Section Diameter (in.)	Minimum Inside Diameter (in.)	Maximum Inside Diameter (in.)
Size - 0	0.04 to 0.07	0.031	5.25
Size - 1	1/16 (0.063)	0.0625	9.75
Size - 2	1/8 (0.125)	0.1875	18
Size - 3	3/16 (0.188)	0.4375	11.5