Buy Fibre Washers Online in Australia
Fibre Washer Sizes — Quick Reference
Fibre washers (compressed fibre or rubber-bonded sealing washers) provide a soft, compressible sealing face for bolted joints, fittings and pipe connections — sealing fluid and gas where metal-to-metal contact won't reliably seal. Available in compressed fibre (general-purpose) and rubber-bonded fibre (Dowty-style, for higher pressure or vibration). AIMS stocks standard metric and imperial sizes.
| Nominal Size | Inside Ø | Outside Ø | Thickness | Best For |
|---|---|---|---|---|
| 1/8" BSP | 9.5 mm | 14.0 mm | 1.5 mm | Hydraulic port plugs, light pipework |
| 1/4" BSP | 13.0 mm | 19.0 mm | 1.5 mm | Pneumatic fittings, instrument tubing |
| 3/8" BSP | 17.0 mm | 24.0 mm | 1.5 mm | Pipe unions, fittings |
| 1/2" BSP | 21.0 mm | 30.0 mm | 2.0 mm | Hydraulic + water pipework |
| 3/4" BSP | 27.0 mm | 36.0 mm | 2.0 mm | Larger hydraulic + plumbing |
| 1" BSP | 34.0 mm | 43.0 mm | 2.0 mm | Heavy pipework, large valves |
| M14 Drain Plug | 14.0 mm | 20.0 mm | 1.5 mm | Automotive engine sump plugs |
| M16 Drain Plug | 16.0 mm | 22.0 mm | 2.0 mm | Larger automotive sump plugs |
| M22 Drain Plug | 22.0 mm | 30.0 mm | 2.0 mm | Heavy vehicle sumps, gearbox drain |
For higher-pressure applications (hydraulic, pneumatic) use bonded/Dowty washers — see our Dowty washer guide for parallel-thread vs tapered-thread selection. For general fastening washers (non-sealing), see flat washers. For thread sealing alternatives, see thread sealants.
Fibre Washers
Fibre washers (compressed fibre or bonded fibre sealing washers) provide a soft, compressible sealing face at bolted joints, fittings and pipe connections — sealing against fluid and gas leakage where a metal-to-metal joint would not seal reliably. AIMS Industrial stocks fibre washers in compressed fibre and rubber-bonded grades for plumbing, hydraulics, pneumatics and general engineering sealing applications.
How Fibre Washers Work
When a bolted or screwed joint is tightened, the fibre washer compresses slightly under the load — conforming to minor surface irregularities on both faces and creating a continuous sealing contact around the bore. This is particularly effective at pipe union faces, valve body sealing faces, hydraulic port plugs and inspection covers where machining tolerances or surface finish would otherwise allow fluid seepage under working pressure. Fibre washers are a sacrificial sealing component — they are designed to be replaced each time the joint is disturbed.
Material Types
Compressed fibre (CAF — compressed asbestos fibre replacements, now made from aramid, glass or vegetable fibre) is suitable for water, oil, fuel and low-pressure steam applications up to moderate temperatures. Rubber-bonded fibre washers provide better sealing on rough faces and are used in hydraulic fittings and fuel system connections. For high-temperature and high-pressure applications, copper sealing washers or PTFE-face washers may be the more appropriate solution.
Sizing
Fibre sealing washers are sized by inside diameter (bore to match the fitting or bolt) and outside diameter (sealing face area), in metric and imperial series to suit standard pipe fittings, bolt sizes and hydraulic port plugs. For help identifying the right sealing washer for your application, contact our team. AIMS Industrial has been supporting Australian industry since 1988.
People Also Ask — Fibre Washers
Q: What's fibre washer made from?
Industrial fibre washers are typically made from vulcanised vegetable fibre, paper fibre, or compressed cellulose. They're cost-effective sealing washers used in low-pressure applications where oil, fuel, or water needs a soft conforming seal between two metal faces. Different fibre types handle different fluids — check the manufacturer's compatibility data before specifying for non-standard fluids.
Q: When should I use a fibre washer vs an O-ring vs a copper washer?
Fibre washers suit oil and fuel sump plugs, banjo bolts, and similar low-pressure flange sealing in automotive and small-engine applications. O-rings handle higher pressure and reciprocating seals. Copper washers (annealed) suit high-temperature sealing where the metal-to-metal contact handles heat and pressure but needs a soft layer to conform. Match the washer to the pressure, temperature, and fluid.
Q: Are fibre washers reusable?
Typically no. Once compressed, the fibre takes a set and doesn't re-seal as effectively on the second installation. For cheap consumables on routine sump plug or banjo bolt changes, replace each service. Some softer fibre washers can be reused once if not significantly deformed, but the cost of a leak from a worn-out washer far outweighs the few cents saved on replacement.
Q: What sizes should I stock for general workshop work?
Common automotive sump plug sizes: 10mm, 12mm, 14mm, 16mm, 18mm, 20mm inside diameter. Common banjo bolt sizes: 10mm, 12mm, 14mm. Industrial small-flange sizes: 1/4 inch, 3/8 inch, 1/2 inch BSP. A workshop assortment kit covering 10-20 common sizes saves stop-work to source individual sizes for routine maintenance jobs.
Q: Why does my fibre washer keep leaking?
Common causes: washer was reused beyond its useful life (replace with new), washer faces aren't clean (residual gasket sealant prevents proper seating), washer thickness wrong for the application (too thin doesn't fill the joint, too thick crushes unevenly), or the metal faces are damaged (scored or pitted faces won't seal regardless of washer quality). Resurface the metal faces if damaged, then use a fresh washer.