Vacuum Equipment Seals Manufacturer Guide: Choosing a 5 mm Flat Rubber O-Ring

Start with the tube interface

The right seal starts with the joint, not the material name. Our custom 5 mm flat rubber O-ring is made for vacuum tube applications and has a flat profile that can suit tube connections requiring an airtight seal. Standard sizes include M2, M3, M8, and M10, while custom dimensions are available for a specified interface.

Before requesting a quote, record the mating surfaces, available seal space, groove or seat dimensions, and whether the seal is being replaced from a sample. A 5 mm profile may be suitable where the assembly is designed for that thickness, but the surrounding hardware determines whether it can seat correctly. Send a drawing or a sample when the existing geometry is difficult to measure.

Match the elastomer to the operating medium

The sealing medium and temperature should determine the rubber selection. As a Vacuum Equipment Seals Manufacturer, we supply this flat seal in NBR, Silicone, EPDM, FKM, FFKM, CR, PU, and PTFE. Each option suits a different working condition:

• NBR suits petroleum oils, gasoline, and diesel. Its listed temperature range is -40°F to 250°F.
• EPDM suits steam, ultraviolet exposure, and brake fluids, with a listed range of -60°F to 300°F.
• FKM fits high-temperature petroleum and silicone oils, with a listed range of 0°F to 390°F.
• Silicone suits vegetable oil, water, and ozone, with a listed range of -90°F to 430°F.
• FFKM is intended for the most extreme chemical media, with a listed range of 0°F to 600°F.

CR, PU, and PTFE are also offered as material options in the product line. For these materials, send the contact medium and temperature to us so we can match the compound to the application instead of treating every tube seal as interchangeable.

Use hardness to refine the fit

Hardness ranges from 30 to 90 Shore A. Hardness affects how the seal conforms to the mating surfaces and how it behaves during installation. A softer grade can be considered when the joint needs more compliance, while a harder grade may suit a firmer seating requirement. The correct point within the range depends on the groove, compression, contact surface, and operating conditions.

Include the target hardness in your drawing or inquiry when it is already defined by your equipment design. If it is not defined, send the joint dimensions, medium, temperature, and sealing motion. We can then discuss the suitable specification for the custom part.

Check dimensions before choosing a custom version

A custom dimension is appropriate when the standard M2, M3, M8, or M10 options do not match the tube assembly. The product line supports custom sizes and hardness specifications, so the order should be tied to the actual sealing interface rather than a general O-ring description.

Picture a maintenance team replacing a seal on a vacuum tube. If the old part is available, keep it uncut and send it as a sample for measurement. If the part is not available, send the groove diameter, mating diameter, seat width, seal thickness requirement, and any drawing tolerances you use. These details give us a working basis for the custom geometry.

Material choice also changes the purchasing decision. A tube exposed to petroleum oil should be reviewed against NBR, while a high-temperature chemical connection may call for FKM or FFKM. A water and ozone environment points toward Silicone. The seal size and compound must be considered together.

Select the production route for the part

We make these seals through compression molding or CNC machining. Compression molding is suited to molded custom parts, while CNC machining can support custom geometry and mold development. Tell us whether the order is based on a standard size, a new drawing, or a physical sample so we can review the appropriate route.

The product is packed in a PP bag inside a carton box. For a replacement program, keep the model, material, hardness, dimensions, and application media together in your internal purchasing record. That prevents a later reorder from matching the diameter while changing the compound or hardness.

Questions to settle before ordering

Send the interface details with your inquiry

The custom 5 mm flat waterproof rubber O-ring seal is the suitable starting point for vacuum tube projects that need a 5 mm flat profile, custom dimensions, and material selection by medium and temperature. Send the tube drawing or sample, seat dimensions, medium, temperature, hardness target, quantity, and required material for a quote.