Brass — a 60% copper, 40% zinc arc- or flame-sprayed coating — is the honest answer when a project wants a solid-brass look without the solid-brass price tag. We spray it most often as a decorative overlay on steel, aluminum, or resin armatures — architectural hardware, restoration trim, sculpture, signage, light fixtures. The steel does the structural work; the brass does the visual work. Topcoats run 3-10 mils over a zinc or NiAl bond coat that carries adhesion and protects the substrate if the brass ever wears through.

As-sprayed hardness lands in the 80-150 HV range — softer than wrought bar, harder than annealed brass — which is what decorative and restoration work wants: opaque coverage, machinable and polishable after spray, friendly to patina and lacquer finishes. It's also the right answer for mild bearing and anti-galling duty: pump sleeves and bushings in mild water service, valve trim in non-aggressive flow, plumbing-industry restoration, and the occasional musical-instrument rebuild. For seawater work specify the naval-brass (C46400) variant with a tin addition to resist dezincification. Service temperature is comfortable to ~250°C — this is not a high-temperature coating.

Restoring a historic railing, rebuilding a pump sleeve, or wrapping a sculpture core in authentic metallic brass? Send us the drawing — we'll scope the bond coat, thickness, and finish path to match the duty.

Technical data

Hardness: 80-150 HV as-sprayed typical arc/flame-sprayed yellow-brass coatings (60Cu-40Zn family) — softer than wrought bar (wrought CuZn40 R400 temper runs ~120-150 HV, full-hard cartridge brass runs 175-185 HV); work-hardening during spray plus oxide content lifts the deposit hardness above the annealed-brass baseline (~65 HV) but the coating is still intentionally a soft, ductile, machinable overlay
Bond strength: Tensile adhesion 2,000-6,000 psi (14-41 MPa) typical for non-ferrous arc-sprayed coatings on grit-blasted steel; best practice is a low-carbon-steel or zinc/NiAl bond coat beneath the brass to lift adhesion into the 4,000-6,000 psi range; HVAF-class copper/brass/bronze deposits can reach >75 MPa (~10,900 psi) on properly prepared substrates
Max service temp: ~400-500°F (200-260°C) continuous — above ~250°C the alpha-beta brass starts to lose strength and zinc volatilization accelerates; not a high-temperature coating
Max service temp: ~200-260°C continuous; decorative/architectural exposure is typically room-temp to outdoor-weather range well inside this envelope
As-sprayed porosity: Arc-spray brass typically 5-12% as-sprayed; tightly parameter-controlled arc deposits at high wire-feed rate drop to ~4-5%; flame-spray wire deposits run similar; HVAF copper-alloy deposits go under 0.5%
Typical thickness: Decorative topcoats 3-10 mils (75-250 microns) to achieve full opacity and polish depth; dimensional restoration on pump sleeves and bushings 15-40 mils; thick repair builds up to 60-80 mils practical before machining

Where it earns its keep

Authentic metallic brass appearance at a fraction of the cost and weight of solid brass — the honest answer for architectural and decorative restoration
Applies to steel, aluminum, resin, and even wood substrates — opens up decorative work to cheap structural cores with a premium finish
Soft and machinable (80-150 HV) — takes polish, satin-brush, or patina finishes readily after spray
Good electrical and thermal conductivity relative to ferrous coatings — useful in shielding and contact applications
Anti-galling against steel mates — the soft copper-alloy matrix prevents adhesive wear on carbon-steel shafts in bushing service
Arc-spray and flame-spray wire economics are favorable — no HVOF price tag, fast coverage over large decorative areas

Where it doesn't

Soft coating — 80-150 HV is NOT a wear coating for hard-particle abrasion or erosion; pick tungsten carbide, aluminum bronze, or Stellite if the duty is aggressive wear
Low service temperature — keep under ~250°C continuous; zinc volatilization and alpha-beta phase softening degrade the deposit above that
Bond strength is modest on direct-to-steel arc-spray; a zinc or low-carbon-steel bond coat under the brass materially improves adhesion and corrosion performance
Dezincification in aggressive water — yellow brass is susceptible; specify naval-brass (C46400, +0.75% Sn) variant or a bronze alternative for chloride-rich or seawater duty
Not a cavitation or erosion coating — pump impellers in abrasive slurry or high-velocity service need a different chemistry
Porosity is real (5-12% arc-sprayed) — for decorative work, seal with wax or lacquer; for bearing service, impregnate with oil or PTFE suspension to close the open porosity
Sprayed brass is NOT a primary corrosion coat — it is a decorative and mild-service overlay; if corrosion protection is the duty, build the stack properly: zinc/aluminum sacrificial base, then brass decorative topcoat

Which process, when?

Twin-wire arc spray is the production workhorse for brass decorative and restoration coatings — fast, high deposition rate, practical over large architectural surfaces, 5-12% porosity that's fine for decorative and bearing-overlay work. Typical arc parameters: 24 V, 240 A, 100 mm standoff, wire feed tuned to deliver thicker denser deposits at higher feed rates. Flame-spray wire (oxy-fuel combustion) is the quieter, more portable option for smaller shops and on-site restoration work — slightly softer deposits, comparable porosity, and friendly to heat-sensitive substrates like wood and resin when parameters are pulled back. HVAF copper-alloy is the dense, low-oxide alternative (>75 MPa bond, <0.5% porosity, 160-185 HV) for engineering applications where near-theoretical density and high conductivity matter — electronic-packaging heat-conductive layers, annealing-roll conductive surfaces — but HVAF is overkill for architectural decorative duty. Pick arc-spray for coverage and cost, flame-spray for portability and substrate-friendly heat, HVAF when density and conductivity are the mission.

Sources

Data points on this page draw on the following published references. Nothing here replaces a material-specific review by our process engineers — but it's the working starting point.

AFT Fluorotec — Brass Thermal Spray Coatings
“Brass can be sprayed onto lower-cost substrates such as steel, resin, and wood to achieve a metallic finish without the cost and weight of solid brass, with applications in architectural metalwork and wrought iron fittings. Applying a zinc undercoat to steel before the brass topcoat improves corrosion resistance and achieves a durable decorative finish far more cost-effective than manufacturing from solid brass.”
Int'l J. Advanced and Applied Sciences — Effect of Spraying Parameters on Surface Roughness, Deposition Efficiency, and Microstructure of Electric Arc Sprayed Brass Coating
“Optimized electric arc spray parameters identified as 24 V, 240 A, 100 mm spray distance; increasing wire feed rate from 2 to 12 cm/s decreased porosity from 12.59% to 4.33% and increased coating thickness to 699 microns; deposition efficiency increased with decreased surface roughness.”
Kermetico HVAF — Copper, Brass & Bronze Coating Equipment and Specifications
“HVAF-sprayed copper, brass, and bronze coatings exhibit hardness 160-185 HV300, bond strength >75 MPa, apparent metallographic porosity <0.5%, oxygen content 0.30-0.40 wt%; near theoretically dense, non-oxidized, physical properties comparable to bulk tough-pitch copper with excellent bonding to steel and aluminum.”
Oerlikon Metco DSMTS-0009.7 — Copper and Copper Alloy Thermal Spray Wires
“Oerlikon Metco brass and copper-alloy thermal spray wires are documented with product codes and recommended application via electric arc spray (Metco 16E family) and flame spray wire systems for decorative, restoration, and conductive-layer applications.”
Metallisation Ltd — Introduction to Metal Spray for Corrosion Protection
“Architects and designers request low-cost steel items be thermally sprayed with bronze and/or brass on top of a thermally sprayed zinc base, enabling long-lasting decorative items produced far more cost-effectively than solid bronze or brass.”
VII Plus — What Is Naval Brass (C46400 / CW712R)
“Naval brass C46400 contains ~60% Cu, 39.25% Zn, 0.75% Sn; tin addition enhances corrosion resistance against seawater, acting as a dezincification inhibitor and slowing the destructive process in chloride service.”
Matmatch — EN 1652 Grade CuZn40 (Yellow Brass) Material Properties
“CuZn40 is a 60Cu-40Zn yellow-brass wrought alloy; unhardenable by heat treatment, strength and hardness achieved by cold work; base-annealed hardness ~65 HV, work-hardened tempers reach 120-150+ HV.”
MDPI Metals — Oxide-Free Wire Arc Sprayed Coatings: Enhanced Adhesive Tensile Strength
“Bond strengths of non-ferrous arc-sprayed coatings typically range 14-41 MPa; solid-wire coatings can reach 46 MPa; a low-carbon-steel or zinc bond coat under a non-ferrous topcoat materially improves adhesion.”

Material data on this page is provided as a general reference and can vary by lot, substrate, and application. Contact HTS to confirm the right material and specification for your specific part.

Brass

Technical data

Where it earns its keep

Where it doesn't

Typical applications

Wear modes addressed

Industries

Substrates

Which process, when?

Sources

Thinking about Brass for a part?