A plating and finish specification should state the base metal, every plating layer in order, the minimum thickness of the top layer in microns, any protective coating, the colour standard, the compliance limits, and how each point will be tested. Written that way, it turns "good quality gold plating" into something you can measure and enforce.
Keep it to one page per finish, attach it to every purchase order and refer to it in every quote.
What to include
- Base metal: for example brass, copper or zinc alloy, and lead-free where required.
- Underlayers: for example copper, then a nickel-free barrier layer. State nickel-free plating if you sell in the EU or want a hypoallergenic claim.
- Top layer: metal and colour, such as gold of a stated carat colour, rose gold or rhodium.
- Minimum thickness: in microns, measured on significant surfaces, the parts that are visible and touched.
- Coating: anti-tarnish lacquer or e-coat, if used, and on which parts.
- Colour standard: a sealed master sample for each colour, since printed colour cards do not show metal colour well.
- Finish: high polish, matte, satin, antique or oxidised, with a reference sample.
- Compliance: nickel release, lead and cadmium limits for your market.
How each point is tested
- Thickness: XRF measurement on a set number of pieces per lot.
- Adhesion: tape test or bend test on sample pieces.
- Corrosion: an artificial sweat test or a salt spray test for an agreed number of hours.
- Colour: visual comparison with the master sample under daylight-type light.
- Nickel, lead and cadmium: lab tests by an accredited lab.
- Visual defects: AQL inspection with an agreed defect list.
Common mistakes
- Writing micron gold without a number.
- Specifying thickness without saying where it is measured.
- Using one colour sample for several plating batches without a tolerance.
- Forgetting the findings: clasps, hooks and backs need the same rules.
- No reference to compliance limits, so nickel underlayers slip in.
What this means for a buyer
Write the specification once, use it with every maker, and test against it. It also makes quotes easier to compare, as our guide to comparing quotes from Rajkot makers explains. Creston & Co works for buyers only, for a fixed fee agreed in writing: we turn your requirements into a written specification, check production against it, have samples tested at NABL-accredited labs and supervise packing. Ask for a free sourcing review.