aseanzip_boss · 1 hour agoZinc-Diecast-Blisters is one of the recurring questions on finishing forums — and most first answers jump to a single fix. There isn’t one: the symptom has several causes, each confirmed differently.
Triage: symptom → confirm → first move
| Blister pattern | Likely root | Confirm by | First move |
|---|---|---|---|
| After plating bake only | Sub-surface porosity out-gassing | 200 °C re-bake test | Quarantine casting lot |
| Random single blisters | Oil or wax under deposit | Blister cross-section | Pre-clean audit |
| Edges and thin walls | Over-etch or acid dwell | Etch weight loss check | Cut acid time, verify strike |
| On flat faces in rows | Air trapped by rack angle | Position map | Re-rack angle 10–20° |
| Whole lot, every load | Casting gas content | Density / lot tag audit | Push back to foundry |
The routine
- Photograph the part before touching it — the pattern is evidence
- Confirm by the column: don’t treat before you know
- Run one corrective action only; verify before the next
- Log everything on the tank card
Safety: bake ovens hold hot parts; hydrogen from pickled parts is real. Heat gloves, face shield, never load pickled zinc straight into a hot oven.
Full version — fixes with parameter windows, FAQ and case study:
Zinc-Diecast-Blisters: How to Diagnose and Fix It Right | QLQ Guide