325 mesh denotes 325 wires per inch in each direction. For twill weave wire mesh the governing document is ISO 9044 / ASTM E2016; the specification row, aperture-micron conversion and selection guidance for this count follow.
325 Mesh Specification Row (ISO 9044 / ASTM E2016)
| Mesh count | Wire diameter (mm) | Aperture (mm) | Micron rating (u00b5m) | Open area (%) | Weight SS (kg/mu00b2) | Reference standard |
|---|---|---|---|---|---|---|
| 325-Mesh | 0.040 | 0.038 | 38 | 23.8 | 0.27 | ISO 9044 |
325 Mesh to Micron & Aperture
| Openings per inch | 325 |
|---|---|
| Aperture (opening width) | 0.042 mm |
| Micron rating | 42 µm |
| Standard wire diameter | 0.036 mm |
| Open area | 29 % |
Aperture = (25.4 mm ÷ mesh count) − wire diameter. The micron rating equals the aperture in micrometres; actual retention also depends on particle shape and cake formation.
Wire Diameter Options at 325 Mesh
| Option | Wire dia | Aperture | Micron | Open area | Weight (SS) |
|---|---|---|---|---|---|
| Heavy wire | 0.047 mm | 0.031 mm | 31 µm | 16.1 % | 0.37 kg/m² |
| Standard wire | 0.036 mm | 0.042 mm | 42 µm | 29.1 % | 0.22 kg/m² |
| Fine wire | 0.027 mm | 0.051 mm | 51 µm | 42.8 % | 0.12 kg/m² |
Heavier wire adds strength and abrasion life but closes the aperture; finer wire opens the aperture and raises throughput at the cost of durability. Specify mesh count AND wire diameter to fix the aperture unambiguously.
Open Area & Flow at 325 Mesh
The standard 325 mesh weave presents an open area of about 29%. A common design rule is to keep the clean-mesh approach velocity low enough that initial pressure drop is negligible; the mesh then acts as the cake support.
325 Mesh Cloth Weight
Standard 325 mesh stainless cloth weighs approximately 0.27 kg/m² (density 7.93 g/cm³ basis; brass and copper weave roughly 10% heavier, aluminum about one third). Use this figure for roll handling and freight estimation.
Typical Applications for 325 Mesh Twill Weave Wire Mesh
325 mesh twill weave wire mesh is commonly specified for liquid filtration and clarification, extruder screen packs, hydraulic and fuel strainers, pharmaceutical and food sieving, and laboratory test work.
Plain, Twill or Dutch Weave at This Rating?
Twill weave passes each weft over and under two warps, which allows a heavier wire at a fine count than plain weave can accommodate. Specify twill when the aperture is fine but the cloth still needs body — typically 200 mesh and finer.