A painted part is made at the hanging station: orientation decides where paint lands and masking decides what stays bare. Both are set before the gun is ever pulled.
This junior guide covers hanging and masking rules for rack painting zinc alloy hardware: orientation, mask selection, overspray zones and the first-rack check.
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. Parts hung without drain | Pools and runs | Orient drain points down |
| 2. Masking skipped | Paint on contact areas | Mask per drawing |
| 3. Wrong mask material | Lift or bleed | Match mask to paint |
| 4. Overspray zones ignored | Neighbour parts fogged | Space and shield |
| 5. Hooks dirty | Part falls or moves | Clean hooks per schedule |
| 6. First rack unchecked | Batch repeats the fault | Check before spray |
| 7. Masks reused too long | Mask failure | Replace per usage |
| 8. No hang log | Faults untraceable | Log hang and mask |
Best Practices That Hold Up in Production
The operating disciplines that separate a reliable line from a reactive one.
- Hang parts with drain points down
- Mask per the part drawing
- Match mask material to the paint system
- Control overspray zones with spacing and shields
- Check the first rack before spraying
Implementation Roadmap
A practical sequence that can be adapted to your own project.
Process Flowchart
Hang and mask flow
A step-by-step sequence with notes and cautions so every shift follows the same order.
- Drain points down stop pools and runs.
- Overspray zones need spacing and shields.
- Never spray a rack with loose parts.
- Masks must be compatible with the solvent.
Working Data & Formula Notes
Hang and mask data
Reference values for rack painting preparation.
| Component / Parameter | Working Value / Role | What Changes Mean (annotation) |
|---|---|---|
| Orientation | Drain points down | Pools and runs follow orientation |
| Masking | Per drawing | Bare areas are functional |
| Overspray zone | Per part geometry | Fog marks neighbours |
| First rack | Check before spray | Cheap check, expensive batch |
Reference Data
Specifications and references cited in this guide. Confirm final parameters with your line supplier.
Mask selection
| Area | Mask type | Why |
| Threads | Caps or plugs | Keep functional |
| Contact points | Tape or plugs | No paint on contacts |
| Recesses | Formed plugs | Prevent pooling |
Implementation Cases
Case 1 - runs from upside-down frames
Situation. Frames came out with runs at the bottom edge; they were hung with a pocket that trapped paint.
Approach. Orientation was changed so drain points faced down, and the hang drawing was posted at the station.
Outcome. Runs stopped; the hang drawing became the standard.
Case 2 - fogged parts from ignored overspray
Situation. Adjacent parts on the rack showed fine overspray fog; the rack spacing was too tight for the part geometry.
Approach. Spacing was increased and shields were added at the fog zones.
Outcome. Fog disappeared; the spacing rule was written on the rack card.
Frequently Asked Questions
Why hang drain points down?
Paint flows with gravity; wrong orientation pools paint and causes runs.
Why mask per drawing?
Threads, contacts and functional surfaces must stay bare; the drawing defines them.
What mask material?
One compatible with the paint solvent - wrong material lifts or bleeds.
What is an overspray zone?
The area where the gun's fog can reach; spacing and shields control it.
Why clean hooks?
Dirty hooks let parts move or fall, causing skips and damage.
Why check the first rack?
A hang or mask error repeats for the whole batch; the first rack is the cheap check.
How long do masks last?
Per usage rules; over-used masks fail and cause bleed.
What do I log?
Hang orientation, mask version and the first-rack check per batch.
Who sets the hang drawing?
Engineering with painting, because orientation is a paint input.
What Would You Like to Solve?
Send us your part drawings and rack types. We can help set the hang orientation, mask selection and overspray control for your rack painting 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.