Question 1

What types of gaskets does Universal Gaskets manufacture?

Accepted Answer

We manufacture soft-cut gaskets (rubber, PTFE, compressed fibre), semi-metallic gaskets (spiral wound, Kammprofile), metallic gaskets (ring joint, solid metal), and custom-engineered gaskets to drawing. See our Gasket Selection Guide for a full overview.

Question 2

What industries do you serve?

Accepted Answer

We supply gaskets to industries including oil and gas, petrochemical, mining, water and wastewater, food and beverage, pharmaceutical, power generation, defence and aerospace, marine, renewable energy, HVAC, and general industrial and MRO, among others. See our Industries page for the full list of sectors we serve.

Question 3

Do you make custom gaskets?

Accepted Answer

Yes. Custom gaskets are a core part of our business. We can manufacture to your drawing, sample, or specification in the materials and sizes you need. See our Measurement & Drawing Guide for tips on providing the right dimensions.

Question 4

Where are you located?

Accepted Answer

We are based in Blacktown, NSW. Visit our Contact page for our full address and enquiry form.

Question 5

Can you replicate a gasket from a physical sample?

Accepted Answer

Yes. Our Reverse Engineering capability traces the gasket profile from a calibrated photograph, either on-site or in our workshop. We've traced decades-old gaskets with no surviving drawings; for worn or complex profiles this is usually faster than measuring by hand.

Question 6

What is the difference between a gasket and a seal?

Accepted Answer

A gasket sits between two stationary surfaces — typically flanges — and a bolt load compresses it to prevent leakage. A seal, such as an O-ring or lip seal, works in dynamic applications where one surface moves relative to the other (a rotating shaft, a reciprocating piston). People use the terms interchangeably in everyday speech, but the distinction matters when specifying parts: gaskets need clamping force; seals need interference fit or spring-loaded contact.

Question 7

How do I choose the right gasket material?

Accepted Answer

Material selection depends on your operating temperature, pressure, the media being sealed, and the flange type. Our Gasket Selection Guide walks through the decision process, and our Chemical Compatibility Database lets you check material resistance to specific chemicals.

Question 8

What is the difference between EPDM and Nitrile (NBR)?

Accepted Answer

EPDM resists water, steam, ozone, and UV exposure, making it well suited to outdoor and water-service applications, but it swells and degrades in petroleum-based fluids. Nitrile (NBR) is the standard choice for oils, fuels, and hydraulic media, though it is vulnerable to ozone, UV, and weathering. EPDM typically operates from around −50 °C to +150 °C, while NBR covers −40 °C to +120 °C. See our Sheet Rubber Selection Guide for a side-by-side comparison of all common elastomers.

Question 9

What does Shore hardness mean for gaskets?

Accepted Answer

Shore A hardness measures the firmness of an elastomer. Lower values (40–50 Shore A) are softer and conform better to irregular surfaces, while higher values (70–90 Shore A) are firmer and resist extrusion under high pressure. Most sealing elastomers fall in the 60–90 Shore A range. Our Shore Hardness & Properties page explains the scale with everyday examples.

Question 10

How do I choose the right gasket thickness?

Accepted Answer

As a general rule, use the thinnest gasket that will achieve a reliable seal. Thinner gaskets offer better blowout resistance (less cross-section exposed to internal pressure) and lower long-term creep relaxation. Thicker gaskets — typically 3 mm — are appropriate when flange faces are damaged, corroded, or not perfectly parallel, because the extra material can compensate for surface irregularities. Our Gasket Selection Guide covers thickness considerations alongside material and type selection.

Question 11

What is the difference between compressed fibre and PTFE sheet gaskets?

Accepted Answer

Compressed Non-Asbestos Fibre (CNAF) gaskets are a cost-effective general-purpose option with good torque retention at moderate temperatures and pressures. They work well in water, oil, and gas services up to around 260 °C depending on the binder. PTFE sheet gaskets are chemically inert and (in FDA-compliant grades) food-safe, suiting them to aggressive chemicals, pharmaceutical, and food-processing services. PTFE can cold-flow (creep) under sustained load and requires smooth, well-aligned flange surfaces. See our Sheet Rubber Selection Guide and Materials section for detailed property data.

Question 12

What are the temperature and pressure limits of different gasket types?

Accepted Answer

Limits vary widely by gasket type and material. As a rough guide:Rubber: 120–230 °C depending on elastomer (EPDM ~150 °C, FKM ~205 °C, silicone ~230 °C)Compressed fibre (CNAF): up to ~260 °CPTFE: up to 260 °CFlexible graphite: 450 °C in oxidising air, higher in non-oxidising serviceSpiral wound (graphite-filled): 450 °C in oxidising air; mica-filled SWGs extend furtherSolid metal / RTJ: well above 500 °C, depending on alloyPressure ratings depend on gasket type, flange class, and size. Our Pressure-Temperature Ratings page provides interactive ASME B16.5 PT curves for common flange materials.

Question 13

What information do I need to order a custom gasket?

Accepted Answer

At minimum, we need the gasket dimensions (ID, OD, and thickness), the material, and the quantity. For flanged gaskets, the flange standard (e.g. AS 2129 Table E, ASME B16.21 Class 150) and nominal size are usually sufficient. Our Measurement & Drawing Guide covers how to measure and specify gaskets correctly.

Question 14

What tolerances do you work to?

Accepted Answer

Our standard manufacturing tolerances follow DIN 7715-5 for cut parts. We can also work to ISO 2768-1 general drawing tolerances or tighter custom tolerances where required. See our Manufacturing Tolerances page for the full tolerance tables.

Question 15

Do you offer material test certificates?

Accepted Answer

Yes. Standard orders include internal quality checks. For critical applications, we can provide material test certificates, formal inspection reports, and first article inspection documentation. See our Inspection & Quality Control page for available options.

Question 16

Do you have minimum order quantities or standard lead times?

Accepted Answer

We have no minimum order quantity for cut gaskets. We will supply a single gasket or thousands. Standard materials are typically available ex-stock, and custom gaskets are typically cut within 2–5 business days for standard materials. Complex profiles or special-order material may take longer. Contact us with your specs and we'll give you an accurate lead time.

Question 17

How tight should I tighten flange bolts?

Accepted Answer

Bolt torque depends on bolt size, grade, lubrication, gasket type, and flange class; there is no single universal value. Bolts should be tightened in a star (cross) pattern across multiple passes at increasing torque percentages. Our Flange Installation Guide covers the full procedure with an interactive bolt sequence tool.

Question 18

Can I reuse a gasket?

Accepted Answer

No. Gaskets should never be reused. Once a joint is broken, the gasket has already taken a permanent compression set and will not seal reliably a second time. The cost of a new gasket is minimal compared to the risk of a leak, unplanned shutdown, or environmental incident.

Question 19

What causes gasket failure?

Accepted Answer

In our experience, the most common culprit isn't material failure; it's undertorqued bolts and dirty flange faces. The Fluid Sealing Association attributes around 85% of gasket failures to improper installation rather than material defects. Common causes include incorrect bolt torque, uneven tightening, dirty or damaged flange faces, and wrong gasket selection. Our Gasket Failure Modes guide provides a visual diagnostic framework.

Question 20

What flange surface finish is required for a good seal?

Accepted Answer

For raised face (RF) flanges, ASME B16.5 specifies a serrated finish of 125–250 μin Ra (3.2–6.3 μm), typically produced by concentric or spiral machining at 45–55 grooves per inch. Flat face flanges use a smoother finish to protect soft non-metallic gaskets. Damaged, corroded, or scored flange faces should be re-machined before installing a new gasket. No amount of bolt torque will compensate for a poor sealing surface. Our Flange Installation Guide covers surface preparation as part of the assembly procedure.

Question 21

Do I need to retorque flange bolts after start-up?

Accepted Answer

For many gasket types, yes. ASME PCC-1 (the bolt-up and joint-integrity standard) covers a "startup retorque" at the same torque value used during assembly, to compensate for gasket relaxation and embedment that occur after initial compression. PTFE-filled gaskets in particular benefit from early retorque, while semimetallic gaskets such as spiral wound types may not require it. Test data summarised in PCC-1 Appendix F shows retorque intervals of 15–60 minutes recover most of the initial stress loss; refer to your gasket-manufacturer guidance and Appendix F for service-specific timing and temperature windows.

Question 22

Can I stack gaskets to fill a large flange gap?

Accepted Answer

No — stacking gaskets is not recommended. We see this in the field more than you'd expect: an emergency-repair stack that becomes the permanent fix. Multiple gasket layers are prone to movement between layers, uneven compression, increased creep relaxation, and a significantly higher risk of blowout. If there is a gap between flanges that a single gasket cannot bridge, the correct approach is to use an incompressible spacer ring (matched to the piping metallurgy) with a standard-thickness gasket on each side. This provides a solid, stable joint without the sealing risks of stacked gaskets.

Question 23

How often do gaskets need to be replaced?

Accepted Answer

There is no universal replacement interval. It depends entirely on the application, operating conditions, and gasket material. A gasket in a mild water service may last many years without issue, while one exposed to high temperatures, aggressive chemicals, or frequent thermal cycling may need replacing within months. Rather than replacing on a fixed schedule, monitor joints for signs of leakage, weeping, or visible deterioration. Any joint that is broken for maintenance should always receive a new gasket. Never reinstall the old one.

Question 24

What is the difference between AS 2129 and ASME flanges?

Accepted Answer

AS 2129 is the Australian standard for flanged connections, using Table designations (e.g. Table D, Table E). ASME B16.5/B16.47 is the American standard, using Class designations (e.g. Class 150, Class 300). The two systems have different bolt hole counts, PCD dimensions, and gasket sizes for the same nominal pipe size. In Australia, AS 2129 Table flanging is most common in general industrial and water/wastewater applications, while ASME flanging dominates in oil, gas, and mining. Our Standard Dimensions & Sizes page provides reference tables for both.

Question 25

What do the colour stripes on spiral wound gaskets mean?

Accepted Answer

The colour band on the outer (centring) ring of a spiral wound gasket identifies the winding material per ASME B16.20; a separate filler stripe identifies the filler. For example, the band yellow indicates 304 Stainless Steel, green indicates 316L Stainless Steel, and orange indicates Monel 400. Our Spiral Wound Gasket Guide has the full colour code reference.

Question 26

How do I convert between metric and imperial units?

Accepted Answer

Our Engineering Conversion Tables page provides an interactive converter for pressure, temperature, torque, length, force, and pipe sizes with fuzzy matching: type a value with a unit and get instant results.

Question 27

What is the shelf life of a gasket?

Accepted Answer

It depends on the material. PTFE and metal gaskets have an essentially indefinite shelf life provided they are stored correctly — PTFE does not degrade chemically over time. Rubber and compressed fibre gaskets are reliable for three to five years under proper storage conditions; beyond that, degradation accelerates with exposure to heat, UV light, ozone, and chemical vapours. Before installing a stored gasket, inspect it for cracking, hardening, discolouration, or permanent deformation.

Question 28

How should gaskets be stored?

Accepted Answer

Store gaskets flat in a cool, dry environment, ideally between 15 °C and 25 °C with relative humidity below 70%. Keep them in their original packaging where possible and away from direct sunlight, UV sources, ozone-generating equipment (such as electric motors), and chemical vapours. Avoid hanging gaskets on hooks or stacking heavy items on top of them, especially PTFE gaskets which can cold-flow and permanently deform under sustained pressure.

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