Scope of this guide
Senior version: the fix set with parameter windows, boundary cases and the discipline that keeps them fixed.
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 |
|---|---|---|---|
| Plating where nothing should plate | Insulation chipped/cracked | Visual under load | Tag rack for rebuild |
| Thickness low on good positions | Current leaking to leaks elsewhere | Position thickness map | Find and retire leaking rack |
| Bath slowly heating / amps drift up | Leak paths multiplying | Amps vs parts trend | Audit racks, not the rectifier |
| Burn marks at rack tips | Contacts arcing | Tip condition photos | Dress contacts, check springs |
| Recurring after one rebuild | Rebuild quality or tape grade | By-rack failure history | Standardise tape spec |
The fix set
- Fix 1 — visual under load — Weekly walk: bubbles where nothing should plate = leak point; tag and pull the rack
- Fix 2 — tape spec — Plating-grade tape/coating per bath chemistry; hardware-store tape dissolves
- Fix 3 — rebuild schedule — Rack age ledger; rebuild by cycles, not by failure
- Fix 4 — tip discipline — Contact tips dressed and sized; arcing tips over-work the rectifier
- Fix 5 — audit gate — New/rebuilt racks get a leak check before entering production
Case method
A line chased low thickness on one position for weeks. The cause was a neighbor rack leaking through cracked tape: current split, the good parts went thin. A leak walk found it in minutes; a rack age ledger kept it from returning. (Method illustration: your own thickness map by rack will show the split.)
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: racks carry live current in acid and alkaline baths. Lock-out before touching, insulate tools, and never straddle two tanks with a rack.
FAQ
How do you run a leak walk?
Weekly, under load: watch for plating/bubbles on non-conducting areas, tag racks, pull the worst.
Rebuild by cycles or by failure?
By cycles with an age ledger — failures arrive at the worst moment otherwise.
Leak check on rebuilt racks?
Mandatory before production: dip test or low-CD load-in and inspect.