Three facts that decide this page
- Brass is pressed, not just cut: small electrical and hardware parts are the classic brass stamping because the material coins and forms cleanly at high speed.
- Seven-tank pretreatment, a 16 ft × 16 ft shot blast chamber, an 18 ft × 14 ft powder booth and a curing oven sit in the same plants as fabrication, so a part is not shipped out and back for coating.
- Copper alloys need a specific conversion coating; the phosphate used for steel is not the right chemistry. Brass also outgasses slightly when heated, which can cause pinholes in a thick powder film, so a staged cure helps. Lacquer is the more common finish where the brass colour must be preserved.
What changes when you powder coat brass
Copper alloys need a specific conversion coating; the phosphate used for steel is not the right chemistry. Brass also outgasses slightly when heated, which can cause pinholes in a thick powder film, so a staged cure helps. Lacquer is the more common finish where the brass colour must be preserved.
The commercial consequence is that brass is priced on its own material line, not blended into a steel rate. Material grade, thickness, tolerance and finish are quoted separately from conversion, so a change of specification is visible in the price.
Tolerance, edge and finish
Ganesh quotes to the drawing first and to ISO 2768 general tolerances where the drawing is silent. For brass powder coating, the practical starting points are in the table below. They are starting points, not a guarantee: the part geometry, thickness and fixturing decide what can actually be held, and the quotation states the tolerance offered.
How Ganesh runs this route
Film thickness is specified and measured, not guessed: 60–80 µm is the usual architectural range and 80–120 µm is used where impact or corrosion exposure is higher. Lead-bearing CuZn39Pb2 machines and shears more freely but is restricted in some markets under RoHS and REACH, so the grade has to be chosen against the destination market, not only the drawing. The route is quoted as one sequence so the customer does not have to coordinate a cutter, a former, a welder and a coater.
When powder coating is the wrong route for brass
Powder coating brass is the wrong choice when the material is chosen for its colour or conductivity. Specify lacquer or plating instead.
A manufacturability review before quotation is the cheapest place to find this out. Send the drawing, material, finish and annual quantity and the review comes back in writing.
Typical parts
- Coloured fittings
- Equipment covers
- Decorative panels
- Signage
Decision rule: when to choose powder coating
Specify powder where you need a durable, single-coat finish with good impact resistance and a wide colour range. Specify wet paint where the part needs a very thin film, a metallic or special-effect finish, or a touch-up-friendly surface. Specify blasting plus a zinc-rich primer plus a topcoat where the service environment is C4 or C5 under ISO 12944 and the part cannot be re-coated in service. For brass the practical constraint is alloy restriction and tarnish: the grade has to satisfy the destination market's substance rules, and the surface needs protection if it must stay bright. Brass is usually a volume material by nature, so the process decision is often already made by the part family; the real choice is the alloy and the temper, and whether the destination market permits the lead content.
What to put on the drawing
State the powder type, the RAL or approved sample, the gloss level, the film thickness range, the masking requirement and the tests expected: adhesion to ISO 2409 or ISO 4624, and salt spray to ISO 9227 with the hours stated. Say what must remain conductive. A coating specification without masking and DFT is a colour request, not a specification.
Quality evidence and inspection
DFT is measured on the production part, adhesion is checked on a sample, and colour is compared against the approved standard under a defined light source. Cure is verified against the powder supplier's window. Coating records sit with the batch, and the pretreatment chemistry is monitored per shift.
What drives the cost
Cost splits into pretreatment, powder, masking, rack loading, cure and inspection. Pretreatment is priced by area and batch; powder by area and film thickness; masking by feature count. A heavy assembly can cost more to cure than a larger, thinner panel of the same area, because oven time follows mass. On brass, material is quoted as its own line at the prevailing rate for the grade and thickness, so a change of specification is visible rather than hidden in a blended rate.
| Specification | brass powder coating | Ganesh limit or note |
|---|---|---|
| Grades | CuZn37 and CuZn39Pb2 strip to ASTM B36 / EN 1652 | Grade per drawing |
| Thickness | 0.3–3 mm strip and sheet | Seven tank: degrease, rinse, derust, phosphate, rinse, passivate, dry |
| Tensile / property | 300–450 MPa depending on temper | 8.4–8.5 g/cm³ density |
| Alloy | CuZn37, CuZn39Pb2 | Lead-free grades where RoHS/REACH applies |
| Thickness | 0.3–3 mm | Below 0.3 mm handling, not the press, becomes the limit |
| Formability | Excellent for coining and drawing | Annealing between draws where depth needs it |
| Powder coating | Seven tank: degrease, rinse, derust, phosphate, rinse, passivate, dry | Chemistry monitored per shift |
| Tolerance basis | ISO 2768-m unless drawing states otherwise | Critical features inspected |
| Finish | Degrease and passivate, or coat where tarnish matters | Specified per part |
Sources and review
- ASTM B36/B36M — Brass plate, sheet, strip and rolled bar · reviewed 2026-11-03
- EN 1652 — Copper and copper alloys, plate, sheet, strip · reviewed 2026-11-03
- EU RoHS Directive 2011/65/EU · reviewed 2026-11-03
- ISO 2409 adhesion and copper alloy pretreatment · reviewed 2026-11-03
Combines Ganesh machine limits (Seven tank: degrease, rinse, derust, phosphate, rinse, passivate, dry) with brass grade and property data. The "what changes" section is written for this material–process pair and is not reused on another page.
Send the drawing and we will check the route
Material, thickness, tolerance, finish and annual quantity are enough for a manufacturability review. Tooling is quoted separately from the piece price.
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