Scope of this guide
Intermediate version: symptom-to-cause triage with the confirm-by column — find the variable, run one change, verify.
Series: finishing.com recurring questions answered with platingclub line practice. Parameters are industry-standard starting ranges — confirm against your supplier TDS.
Triage: symptom → confirm → first move
| Symptom | Likely root | Confirm by | First move |
|---|---|---|---|
| Dull/gray only on edges & points | CD above bright range | Position map vs amps | Cut amps in steps; map again |
| Dull everywhere, worse at high CD | Brightener exhausted or overdosed | Hull cell panel | Hull cell before dosing |
| Dull after bath cools | Temperature below window | Temp log overlay | Hold 50–60 °C Watts band |
| Dull + rough together | Solids on top of CD stress | Filter ΔP + bag check | Filtration first, then amps |
| Dull band follows rack family | Old rack contacts hogging current | By-rack amp compare | Retire/rebuild those racks |
Engineer notes
- One variable per corrective action; verify with the confirm-by column.
- Records beat memory: log every trial on the tank card.
- Two failed actions in a row is a senior call — escalate with your log.
Safety: nickel salts are skin sensitisers; hot acid solutions splash. Face shield at tank, nitrile gloves, eyewash in reach.
FAQ
Hull cell bright band is narrow — meaning?
Brightener out of balance or pH drift; correct by panel, then confirm in production.
Why does a cold bath dull edges first?
High-CD areas need the temperature band most; 50–60 °C keeps the window open.
Dull follows one rack family — bath or rack?
Rack: contacts age and hog current. Compare dull rate by rack age.