Nine times out of ten the answer is stainless. 304 for general work, 316 when there is salt or chemistry involved. We have written about choosing between them, and for most jobs that article is where the decision ends.
This one is about the tenth time — the conditions where stainless does not merely underperform but fails in a predictable way, and where a different alloy is the right specification rather than a luxury.
Monel: Hot Chlorides And Seawater
Monel is a nickel-copper alloy, roughly two-thirds nickel. Its case against stainless comes down to one failure mode.
Austenitic stainless — 304 and 316 both — is susceptible to chloride stress-corrosion cracking. Put it under tensile stress in a warm chloride environment and it can crack rather than corrode gradually: no obvious rust, no thinning, then a fracture. Woven mesh is under tension by nature, which makes it more exposed to this than a plate would be.
Monel is substantially more resistant to that mechanism. It also holds up in hydrofluoric acid and in reducing conditions where stainless struggles, and it does well in flowing seawater.
Reach for it when you have chlorides plus heat, or brine, or seawater in continuous service. We stock it from coarse to fine: 2 mesh, 8 mesh, 30 mesh, and up to 100 mesh for fine filtration.
Alloy 20: Sulfuric Acid
Carpenter 20 — Alloy 20 — exists for essentially one reason: sulfuric acid. It was developed for it, and the copper and molybdenum in it are there to survive it. It also resists chloride stress-corrosion cracking better than standard austenitic grades.
If your process involves sulfuric acid at any real concentration or temperature, 316 is not a cost saving, it is a replacement schedule. We stock 10 mesh and 14 mesh.
Copper, Brass, And Bronze: Three Different Reasons
The copper alloys get specified for properties stainless simply does not have.
Non-sparking. Copper alloys do not throw sparks on impact. Where there is a flammable atmosphere — grain dust, solvent vapour, fine combustible powder — that is a safety property, not a preference, and it is often written into the specification.
Electrical conductivity and RF shielding. Copper mesh is a standard material for electromagnetic shielding, Faraday enclosures, and grounding screens. Stainless is a poor conductor by comparison. If a spec calls for shielding effectiveness, it will usually call for copper or brass.
Appearance and patina. Brass and bronze are chosen on looks as often as on chemistry — grilles, screens, restoration work, architectural panels. Bronze weathers to a stable dark patina; brass stays warmer and brighter. Neither behaves like stainless over years outdoors, which is usually the point.
Bronze over brass in water. Brass contains zinc, and zinc can leach out in aggressive or moving water — dezincification — leaving the metal weakened. Bronze, a copper-tin alloy, has no zinc to lose and is the better choice for marine and wet service.
We stock copper woven from 2 mesh through 10 mesh, brass at 2 mesh and 4 mesh, and bronze from 4 mesh down to 60 mesh.
And 316L, While We Are Here
Not exotic, but worth knowing: the L in 316L means low carbon. Less carbon means less chromium carbide forming at the grain boundaries when the metal is welded, which means better corrosion resistance in the heat-affected zone.
If the mesh is going to be welded into an assembly, 316L is usually the better specification. If it is being cut and installed, standard 316 is fine.
Choosing In One Table
| Condition | Alloy | Why |
|---|---|---|
| General service, dry or mild | 304 | Cheapest adequate answer |
| Salt air, food, mild chemistry | 316 | Molybdenum improves pitting resistance |
| Welded into an assembly | 316L | Low carbon protects the weld zone |
| Hot chlorides, brine, seawater | Monel | Resists chloride stress-corrosion cracking |
| Sulfuric acid | Alloy 20 | Purpose-built for it |
| Flammable atmosphere | Bronze or brass | Non-sparking on impact |
| RF shielding, grounding | Copper or brass | Conductivity |
| Marine, decorative, wet | Bronze | No zinc to leach out |
Two Practical Notes
These are stocked in fewer sizes. 304 and 316 run across hundreds of mesh and wire combinations. The specialty alloys are stocked in a handful each, so the mesh you want may need to be woven to order. Ask early if you have a lead time.
Do not mix metals carelessly. Fastening a copper-alloy screen into an aluminium or galvanised frame in a wet environment sets up galvanic corrosion, and the less noble metal — the frame — goes first. Match the frame to the mesh, or isolate them.
Frequently Asked Questions
Is Monel worth the cost over 316?
Only if your environment triggers the failure mode it protects against — chlorides with heat, or continuous seawater. In mild service it is an expensive 316.
What is the difference between brass and bronze mesh?
Brass is copper-zinc, bronze is copper-tin. Bronze is the better choice in water because it has no zinc to leach out; brass is brighter and often chosen for appearance.
Which mesh for RF shielding?
Copper or brass. The mesh opening also has to relate to the wavelength you are attenuating, so bring the frequency and the required attenuation to the conversation.
Do you stock nickel, or other alloys not listed here?
We hold some nickel, and we can source beyond what is on the site. Call and ask — if we cannot get it we will say so.
Tell Us The Environment
The alloy question is really a question about conditions. Tell us what the mesh will sit in — the chemistry, the temperature, whether it is wet, whether it is welded — and we will tell you what we would specify, and say plainly when 304 will do and you should not spend the money.
See also our material guide. Or request a quote, ask for a free sample, or call (510) 887-8787.
General guidance on alloy selection, not a corrosion engineering assessment. Service conditions vary; for critical applications have the material confirmed against your specific process.