☑ Key Takeaways
- Mark protected surfaces and mask boundaries on the controlled drawing.
- Agree on film thickness, inspection locations and appearance.
- Approve fit and function on a coated sample before production.
Powder coating changes the surfaces your assembly relies on. Use this checklist to tell your supplier what to protect, where to measure the coating and how to check the finished part.
7 Powder Coating Masking Checks
1Protect threaded holes
Mark the thread depth and mask boundary. Verify with the agreed gauge or mating fastener.
2Preserve locating bores
Specify the finished diameter and whether coating is allowed inside the bore.
3Keep grounding pads exposed
Mark the contact area. Specify a continuity check when required.
4Define cosmetic surfaces
Agree on a finish reference, film thickness and measurement locations.
5Control the mask boundary
Show where the coating must stop and agree where rack marks are acceptable.
6Check finished assembly fit
Verify the coated sample with the actual mating parts or specified gauges.
7Compare the same quote scope
Ask every supplier to price masking, sample approval and the same inspection checks.
Drawing & Inspection Comparison
| Feature | Specify on your drawing | Check on the coated sample |
|---|---|---|
| Threaded holes | Thread designation, depth and mask boundary | Check with the agreed gauge or mating fastener |
| Locating bore | Finished diameter and whether the bore is coated | Measure at the agreed locations and verify assembly fit |
| Grounding pad | Protected contact area and boundary | Inspect coverage and verify continuity if specified |
| Visible face | Finish reference, thickness range and measurement locations | Check agreed film thickness and appearance against the sample |
Example: Coating Build in a Bore
Illustrative calculation. A uniform 60 µm film on each wall reduces the clear diameter by about 0.12 mm. Actual coverage varies. Define the finished dimension and verify it on a coated sample.
FAQ: Powder Coating Masking
When should I specify masking?
Before requesting a quote. Give each supplier the same drawing revision and mask boundaries.
Should I mask every hole?
Review each hole by function. Threads, locating bores and cosmetic openings may have different requirements.
Does powder coating change bore size?
Yes. Coating on both walls reduces the clear diameter. Confirm the finished dimension on a coated sample.
How do I approve the first coated sample?
Check mask boundaries, appearance, film thickness and fit using the agreed method.
Can I leave a grounding surface uncoated?
Identify the contact area on the drawing and specify a continuity check if your design requires one.
What should I send for a quote?
Send the marked-up drawing, finish reference, trial and production quantities, and acceptance checks.
Related: LK MFG powder coating capabilities · Xometry’s powder coating process and quality checks
Have a Part to Powder Coat?
Send your marked-up drawing for a review of masking, finish and assembly fit.
