Powder Coatings Troubleshooting Guide
PPG is a global leading provider of coatings, paints and specialty materials, offering solutions in every major technology platform, including powder, liquid, electrocoat, pretreatment, as well as advanced energy curable solutions.
This Powder Coatings Troubleshooting Guide explores possible causes and solutions of errors that can occur in the powder application and finishing process. Please contact your local PPG representative for troubleshooting guides on other coatings technologies.
Click Here to Download Full Powder Coatings Troubleshooting Guide with Images
The tips and techniques described herein are based upon the best information and practices known to PPG Industries, Inc. (“PPG”). Any statements or methods mentioned herein are general suggestions only and are not to be construed as representations or warranties as to safety, performance, or results. Since the resolution of issues is highly dependent on the product user’s processes, operations, and numerous other user-determined conditions, the user is solely responsible for, and assumes all responsibility, risk and liability arising from, the determination of whether the proposed solution is suitable for the user. Continuous improvements in coatings technology may cause future technical data to vary from what is in this bulletin. Contact your PPG representative for the most up to date information.
How to fix air percolating issues while powder coating
No air is percolating through the powder surface.
| Potential Cause | Solution Proposal |
|---|---|
| Insufficient air pressure |
|
| Compacted powder |
|
| Fluid bottom defect |
|
| Fluid bed clogged |
|
How to fix plugged powder coating hoses
Hoses and pumps are plugged from impact fusion.
| Potential Cause | Solution Proposal |
|---|---|
| Normal build-up / routine maintenance not being done |
|
| Air pressure too high |
|
| Moisture in compressed air supply |
|
| Powder is too fine |
|
How to fix powder feed to gun
Insufficient or inconsistent powder feed to gun.
| Potential Cause | Solution Proposal |
|---|---|
| Powder not fluidizing properly |
|
| Insufficient air pressure or volume |
|
| Obstruction in powder supply |
|
| Hoses kinked, crushed or too long |
|
| Worn pump venturies |
|
How to fix build-up up on the powder coating spray nozzle
During powder coating application, powder or effect agent accumulates at the nozzle slot
| Potential Cause | Solution Proposal |
|---|---|
| Wear of the nozzle wedge |
|
| Powder output too high |
|
| Powder too moist |
|
| Effect powder coating: electrostatic charge too high |
|
| Effect powder coating: incorrect powder hose |
|
How to fix poor charging, low film build, insufficient wrap
Recommended layer thickness cannot be achieved; uneven coverage of the component.
| Potential Cause | Solution Proposal |
|---|---|
| Low or no voltage at electrode |
|
| Poor ground |
|
| Powder delivery too low |
|
| Effect powder coating: electrostatic charge too high |
|
| Powder output from guns too high reducing the charging efficiency |
|
| Humidity too low (in case of Corona spraying) | • Control humidity to the proper specification for your system (40-60% RH) |
| Powder too fine | • Adjust virgin / reclaim mixture |
How to fix poor penetration
The powder will not coat in Faraday cage areas.
| Potential Cause | Solution Proposal |
|---|---|
| Voltage: Intensity (µA) too high |
|
| Powder / air velocity too high |
|
| Powder delivery too low |
|
| Improper technique or gun placement |
|
| Improper spray pattern |
|
| Powder too fine | • Adjust virgin/reclaim mixture |
| Part is too close or too far from spray gun | • Reduce or increase distance |
How to fix powder repelling from part/not sticking to part
The powder does not adhere to the surface or it partly falls away.
| Potential Cause | Solution Proposal |
|---|---|
| Poor ground |
|
| Charge too low |
|
| Powder output too high |
|
| Powder too fine |
|
| Fluidity too high |
|
| Film thickness too high | • Reduce film thickness |
| Blow-off effect due to too much conveying air or insufficient distance to the part |
|
How to fix poor powder coating spray pattern
The powder does not adhere to the surface or it partly falls away.
| Potential Cause | Solution Proposal |
|---|---|
| Worn gun parts |
|
| Blockage from impact fusion |
|
| Hoses, pumps, pick-up tubes or guns clogged |
|
How to fix fluctuating layer thickness or uneven coating thickness in powder coating
Irregular layer thickness on the component that is visible or only measurable.
| Potential Cause | Solution Proposal |
|---|---|
| Poor grounding |
|
| Irregular powder output |
|
| Irregular manual application |
|
| Automatic application: irregular gun spacing, incorrect stroke setting, wrong sine curve, etc. |
|
How to fix powder lump formation / agglomeration in the cardboard box
Lump formation in the cardboard box or fluid container.
| Potential Cause | Solution Proposal |
|---|---|
| Storage Temperature and humidity at storage location too high |
|
| Temperature and humidity during transportation too high |
|
| Pressure during storage too high |
|
| Powder is past expiration date |
|
| Conveying from cardboard box |
|
| Poor quality powder coating |
|
Additional questions or concerns?
Please reach out to your local PPG representative for additional guides on other technologies. Or download our full guide, including tips for powder surface defects here. For assistance with your order, reach out to us via our chat window or contact us.