Question 1

What is the difference between NBR, EPDM, and Viton O-rings?

Accepted Answer

NBR (Nitrile/Buna-N) is economical and works well with oils and fuels but not with some chemicals. EPDM excels in water, steam, and outdoor applications but not with oils. Viton (FKM) offers superior chemical and high-temperature resistance but costs more. For water systems, use EPDM. For oils/fuels, use NBR. For chemicals or high heat, use Viton.

Question 2

When should I use PTFE tape vs. PTFE paste?

Accepted Answer

PTFE tape is best for NPT (tapered) pipe threads on metal fittings for water and gas. It's easy to apply and allows repositioning. PTFE paste (pipe dope) works better on larger threads, provides better initial seal, and is preferred for vibration-prone connections. Some applications benefit from both: paste on threads, tape over it.

Question 3

What is a bonded sealing washer and when do I need one?

Accepted Answer

Bonded sealing washers (Dowty seals) have a rubber ring bonded to a metal washer. They're used on hydraulic fittings, brake lines, and high-pressure applications where standard flat washers would leak. The metal washer prevents over-compression while the rubber provides sealing. Essential for vibration-prone connections.

Question 4

How do I select the correct O-ring size?

Accepted Answer

Measure the groove or shaft diameter and cross-section (thickness). O-rings are specified by inside diameter (ID) and cross-section (CS). For standard sizes, refer to AS568 (inch) or ISO 3601 (metric) charts. The O-ring should have 10-25% compression when installed. We provide sizing guides and technical support for selection.

Question 5

Can I reuse washers and gaskets?

Accepted Answer

It depends on the material and application. Brass and copper washers can often be reused if not damaged. Fiber washers should be replaced. Rubber gaskets and O-rings should be replaced in critical applications as they may have compression set. PTFE tape must always be replaced. When in doubt, replace - gaskets are inexpensive compared to leak damage.

Question 6

Are your sealing materials safe for drinking water?

Accepted Answer

Yes, our EPDM gaskets, O-rings, and brass washers designated for potable water use are NSF/ANSI 61 certified. This certification ensures they won't leach harmful substances into drinking water. Always specify potable water application when ordering to ensure you receive NSF-certified materials.

Question 7

What causes O-rings to fail?

Accepted Answer

Common causes include: wrong material for the fluid/temperature, improper installation (pinching, twisting), over or under compression, chemical incompatibility, temperature extremes, and age/UV degradation. Proper material selection, correct groove dimensions, and careful installation prevent most failures.

Question 8

Do you manufacture custom gaskets and seals?

Accepted Answer

Yes, we manufacture custom gaskets, O-rings, and washers for OEM applications and specialty requirements. We can work from drawings, samples, or application specifications. Custom molding available for rubber parts. MOQ varies by type: typically 1000-5000 units. Contact our technical team with your requirements.

Brass Washers Material	Brass CW617N, Copper Lead-free brass and copper washers
Rubber Materials	NBR, EPDM, Viton (FKM), Silicone Various elastomer compounds for different applications
PTFE Materials	Virgin PTFE, Expanded PTFE Thread sealant tape and gasket sheet
Size Range	M4 to M64 (washers), 1/16" to 6" (gaskets) Metric and imperial sizes
Temperature Range	-50°C to 200°C °C Varies by material compound
Pressure Rating	Up to 100 bar Depends on application and material

Brass Seals, Gaskets & O-Rings - Leak-Free Plumbing Solutions

Why Choose Brass Seals, Gaskets & O?

Material Diversity

Precision Manufacturing

NSF Certified Materials

Temperature & Chemical Resistant

Long Service Life

Technical Specifications

Materials

Available Sizes

Where It's Used

Water Supply Systems

Gas Line Installations

Industrial Process Piping

HVAC & Refrigeration

Automotive & Marine

Trusted by Industries

Complete Sealing Solutions

Material Selection Expertise

Quality & Reliability

Certifications & Standards

NSF/ANSI 61

ISO 3601

ASTM D2000

BS EN 681

ISO 9001:2015

Frequently Asked Questions

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