The spray gun is where paint becomes film, and the wet film gauge is the proof. A gun set up right with a checked film makes the difference between first-pass and rework.
This junior guide covers spray gun setup for rack painting: air pressure, fan pattern, distance, and the wet film check every operator should run.
Common Mistakes and How to Avoid Them
The pitfalls that show up most often in real projects, with the cause and the practical fix.
| Mistake | Why It Happens | Practical Fix |
|---|---|---|
| 1. Pressure too high | Overspray and dry film | Set per paint spec |
| 2. Fan pattern distorted | Uneven coverage | Check the air cap |
| 3. Gun too close | Runs and heavy film | Hold the distance |
| 4. Wet film never gauged | Thin or heavy guesses | Gauge every rack start |
| 5. Trigger pulled while moving | Heavy start spots | Start the pass before trigger |
| 6. Gun not cleaned | Blocked nozzle | Clean per schedule |
| 7. Distance varies | Film varies | Mark the distance |
| 8. No setup log | Drift invisible | Log pressure and pattern |
Best Practices That Hold Up in Production
The operating disciplines that separate a reliable line from a reactive one.
- Set pressure per the paint and gun spec
- Check the fan pattern before every rack
- Hold a consistent distance
- Gauge wet film at every rack start
- Clean the gun on schedule
Implementation Roadmap
A practical sequence that can be adapted to your own project.
Process Flowchart
Gun setup flow
A step-by-step sequence with notes and cautions so every shift follows the same order.
- Wet film gauge reads the film before cure.
- Start the pass before the trigger.
- Never point the gun at people.
- Clean the gun before solvent flashes.
Working Data & Formula Notes
Gun setup data
Reference values for rack painting spray guns.
| Component / Parameter | Working Value / Role | What Changes Mean (annotation) |
|---|---|---|
| Pressure | Per paint spec | High pressure oversprays |
| Distance | 15-25 cm typical | Close runs, far dries |
| Wet film | Per product window | Gauge proves the film |
| Pattern | Full and even | Distorted pattern uneven |
Reference Data
Specifications and references cited in this guide. Confirm final parameters with your line supplier.
Wet film guide
| Result | Meaning | Action |
| In window | Correct film | Continue |
| Below | Thin film | Second pass or adjust |
| Above | Heavy film | Reduce passes or adjust |
Implementation Cases
Case 1 - dry film from overspray
Situation. Parts came out rough and dry-looking; pressure was 30% above spec, atomizing the paint into dry overspray.
Approach. Pressure was set to spec, the fan pattern was checked, and wet film was gauged at every rack start.
Outcome. Film returned to window; the setup log caught the pressure drift.
Case 2 - runs from a gun held too close
Situation. Runs appeared on the top rows; the operator held the gun closer to cover the rack faster.
Approach. A distance mark was added in the booth and the wet film check was enforced per rack.
Outcome. Runs stopped; the marked distance became standard.
Frequently Asked Questions
What pressure should I use?
Per the paint and gun spec; high pressure oversprays and dries the film.
How do I check the fan pattern?
Spray a test pass and check the fan is full and even, not distorted.
What distance?
Typically 15-25 cm, marked in the booth for consistency.
How do I gauge wet film?
Press the gauge comb into the wet film and read the highest wetted tooth.
Why gauge every rack?
The first rack shows the setup; later racks show drift.
How do I start a pass?
Begin the movement before pulling the trigger to avoid heavy start spots.
Why clean the gun?
A blocked nozzle distorts the pattern and wastes paint.
What if film is thin?
Add a pass or adjust distance/pressure, then re-gauge.
What goes in the log?
Pressure, pattern check, distance and the wet film result per rack.
What Would You Like to Solve?
Tell us your gun type, paint spec and current setup. We can help set the pressure, pattern and wet film windows for your rack line.
Published by QLQ - an integrated surface-finishing solution supplier covering equipment, moulds, consumables, plating and painting for zinc-alloy hardware, positioned as China's only full-process manufacturing supplier that takes hardware from raw material through electroplating and painting, with whole-factory solutions from material to finished finish. Values cited are project references; confirm with your line supplier before specification.