Scope of this guide
Junior version: what you will see, what you record, and what you never touch. Recognise early, escalate fast.
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 |
Recognise, record, escalate
| You see | You do | You never do |
|---|---|---|
| Zinc peels in sheets | Keep sample, tag load, call senior | Re-plate over the peel |
| Blisters after bake | Check bake log was actually run | Skip bake to save time |
| Water beads on parts | Flag cleaner tank for titration | Send beading parts to zinc anyway |
| Any adhesion doubt | Tank card entry with load id | Ship and hope |
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
Why does zinc peel in sheets?
It never bonded: contamination under the deposit. The peel map points to the stage — cleaner, activate or rinse.
Why bake after zinc plating?
Hydrogen entered the steel during cleaning/plating; the bake drives it out before it cracks parts later.
What do I do with a peeled sample?
Keep it, tag the load, call the senior. The sample is the diagnosis.