Troubleshooting – Surface and Appearance

There are a number of common problem areas when applying powder coating, below you will find details of some of the problems that can occur, and some suggested remedies.

If your problem isn’t listed below, or if you are unsure of how to proceed please do not hesitate to call us on 01473 463333, and we will be happy to talk you through any problem you may be experiencing with applying our powders.

Surface and Appearance

Problem

Possible Cause

Suggested solution

Poor Flow Film thickness is too low
  1.   Measure film thickness with appropriate and   calibrated equipment
  2.   Adjust the thickness by changing the air pressure on the ejectors
Heating up metal too slowly Increase the oven temperature, or adjust the temperature   profile. If possible begin using IR heating in the entrance zone
Spray gun voltage too high Reduce the voltage or increase the distance between the   spray gun and the object.
Inappropriate type of powder   (reactivity too high or powder particles are too coarse) Check with IP & PS Ltd if the powder is appropriate   for the specific use/powder application equipment
Low Gloss on a high gloss finish Contamination with another   product that is not compatible Thorough cleaning of the spray booth , delivery system and   recycling system before adding virgin powder
Extreme temperature stress   during heating Reduce the effect in the IR Zone
Pinholes in the finish Film thickness is too high Reduce the film thickness
Moisture Check if there is moisture in the compressed air or if   drying after the pre-treatment is insufficientCheck the degree of porosity in the substrate (cast Iron)
High gloss on a low gloss finish Insufficient curing Increase the temperature and/or time in the oven
Discolouration in the finish Contamination with another powder used earlier in the   equipment Thorough cleaning of the spray booth, delivery system and   recycling system before adding virgin powder
Contaminated virgin powder Contact IP & PS Ltd for assistance
Specks in the coating finish Sintered powder in the spray guns loosens and adheres to   the object Stop and do a thorough cleaning. Avoid using too much air   pressure
The sieve in the recycling system is not functioning Inspect and repair/replace the sieve if necessary
Impurities from the conveyor or hanging system fall down   in the spray booth Routine cleaning of the conveyor and stripping the hooks
Impurities in the air in the work area are sucked into the   spray booth Physically block off the area around the spray boothGood general cleaningFiltering and regulating the humidity in the work area
Craters in the finish/surface Contamination with another product that is not compatible Stop and do a thorough cleaning before adding virgin   powder
Grease on the metal surface after insufficient   pre-treatment Check and replenish the pre treatment baths
Moisture and/or oil in the compressed air Examine the oil and water separators
Porosity in the coating Moist substrate Check the material after per treatment/drying
The powder is not suitable for the specific substrate Contact IP & PS Ltd
Incorrect or uneven colour Curing conditions exceed the specified range Refer to the product data sheet/label instructions and   make necessary adjustments
Variation in the film thickness Measure the film thickness and make necessary adjustments
Varying substrate thickness Switch to Polyester-based powder coatings
Unsuitable type of powder Contact IP & PS Ltd to discuss whether the powder is   suitable for the specific use and type of oven
Drop formation/sagging Film thickness is too high Check the thickness and make necessary adjustments
Type of coating is unsuitable for the specific use (flow   too good) Contact IP & PS Ltd
Poor coverage of edges Sharp cutting edges on the metal Contact the metal supplier/processor for changesAlternative hanging technique (sharp edges down)
Type of coating is unsuitable for the specific use (flow   too good) Contact IP & PS Ltd