Scope of this guide
Management version: this defect as cost and risk — the metrics, audit points and claim defence.
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 |
|---|---|---|---|
| Peels in sheets, bare steel shows | Surface contamination pre-plate | Water-break + peel map | Pre-clean audit before dosing |
| Blisters after bake | Hydrogen entry + baking missed | Bake log vs spec | Enforce bake window per spec |
| Adhesion fails on high carbon steel | Substrate-specific prep needed | By-alloy pattern | Stronger activate for that alloy |
| Peel at edges after storage | Post-dip/rinse contamination | Storage test samples | Rinse quality check |
| Random scattered failures | Cleaner bath exhausted | Cleaner titration log | Rebalance or dump per trend |
Cost, metrics and defence
| Cost line | Driver | Metric | Lever |
|---|---|---|---|
| Claims | Peel in field | PPM by customer | Bend gate per load |
| Scrap | Late detection at assembly | Adhesion audit failure | Sample plan by load |
| Chemicals | Cleaner dumped late/early | Titration log completeness | Dump on trend |
| Delay | Quarantine loops | Days in quarantine | Bake log compliance |
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: alkaline zinc baths are caustic and hydrogen from pickled steel can ignite. Caustic-rated PPE, no flames near freshly pickled loads, eyewash at the line.
FAQ
Which KPI predicts peel claims?
Cleaner titration compliance and bake log completeness; both drift before claims arrive.
Is 100% adhesion testing worth it?
Sampling per load catches systemic peel; 100% only while a supplier or bath is failing.
What does a peel claim cost vs the gate?
Claims cost freight, credit and trust; the bend gate costs minutes and paper.