Most gold-plated returns are not chemistry failures - they are handling failures that happen in the twenty minutes after the bath. These are the rules that keep a good rack good all the way to the packing table.
minimise
Rack contact
60-70 C
Dry temp
gloved only
Handling
Where handling defects come from
| Stage | Defect | Cause | Fix |
|---|---|---|---|
| Racking | Contact marks | Jig pressure on soft gold | Use spring contacts on a hidden face |
| Rinsing | Water marks | Hard water, slow transfer | DI final rinse, 10 s transfer |
| Anti-tarnish | Streaks | Cold or spent dip | 30-60 s at pH 6.5-7.5, refresh weekly |
| Drying | Scratches | Wiping with cloth | Air-dry at 60-70 C, never wipe |
| Packing | Fingerprints | Bare hands | Gloves + tissue or foam interleaves |
Rack design for cosmetic gold parts
| Feature | Recommendation | Why |
|---|---|---|
| Contact point | Hidden face or inner edge | Visible marks become claims |
| Contact pressure | Light spring, not clamp | Gold is soft and marks easily |
| Titanium vs copper jig | Titanium for gold baths | Longer life, fewer bath impurities |
| Spacing | Visible faces never facing each other | Prevents rubbing in transit |
Final inspection under D65 light
| Check | Method | Pass |
|---|---|---|
| Colour | Compare to the approved sample | Match under D65, not office light |
| Marks | 15 cm viewing distance, both faces | No visible contact or scuff |
| Thickness | XRF witness | Inside the quoted band |
| Pack | One piece per pocket or interleaved | No metal-to-metal contact |
Watch out
A single bare-handed touch after the anti-tarnish dip can print through to the gold in a few weeks. Gloves are not optional on a cosmetic line.
Common mistakes and the fix
| ✗ Wipe the parts dry | ✓ Air-dry only; cloth fibres and abrasives leave scratches |
| ✗ Rack on visible faces | ✓ Move contacts to hidden areas from the start |
| ✗ Reuse spent anti-tarnish dip | ✓ Refresh weekly or when the film looks uneven |
| ✗ Pack parts loose in a bag | ✓ Interleave or pocket them |
What each role watches
| Operator | "Gloves from the anti-tarnish onwards; no exceptions." |
| Chemist | "Check the anti-tarnish pH and film evenness weekly." |
| QC | "Inspect under D65 and keep the approved sample sealed." |
| Manager | "Charge handling damage to the stage that caused it - it stops repeats quickly." |
From the shop floor
Case: a jewellery customer returned 40 watch cases with fine scratches. They came from the drying table: the operator had wiped them with a shop cloth to 'save time'. Air-drying removed the issue the same week.
FAQ
Can parts be re-dipped to hide a scratch?
No. Re-dipping adds thickness but the scratch remains visible; strip and re-plate instead.
How long can plated parts wait before packing?
Keep them covered and dry; overnight is fine if they are in a closed dry box, not open on a bench.
Do I need a cleanroom?
No. A covered drying and packing bench with filtered air is enough for small hardware.
Where to go next
- Level guide for this trade: Gold & Precious Plating — technician levels
- Other levels: Intermediate, Senior, Management
- Owner view: Process Overview for owners
- Supplier view: Chemistry & Supply · Find content by trade + level
Related reading in this trade