Common Paint Defects - Spectrum International

Common Paint Defects and Their Causes

Pops

Description:

• Small swelled area like a blister
  

• Broken edge craters if the blisters burst
  

• Pinpoint holes in finish
  

Causes:

• Excessive film build traps the solvent which is released during flash or bake
  

• Insufficient flash off time before baking
  

Spectrum Preventative Measures:
Controlled application through SOPs and automated equipment prevents excessive film build Adequate flash-off time Multi-zone oven controls promote gentle temperature ramping.

Metallic Inconsistency / Mottling

Description:
Inconsistent flake orientation causing color variation, particularly when viewed at different angles.


Causes:
Oil canning of substrate surface (slight convex or concave distortion)
Batch to batch paint variation Insufficient agitation of paint Inconsistent application techniques Variations in paint film thickness. Part design may necessitate hand spray (returns, framing, recessed areas).

Spectrum Preventative Measures:
Communicate oil canning potential with customer Communicate with customer the effect of part design on painting requirements All incoming and in-house blended paints are inspected for color match in Spectrum's in-house color lab In-process paint agitated for consistency Controlled application through SOPs and automated equipment assures consistent finish and paint film thickness.


Adhesion Failure

Description:

• Flaking or peeling paint between the top coat and primer, or top coat and substrate
  

Causes:

• Improper surface preparation
  

• Painting over oil, grease or other contaminants
  

• Improper paint cure
  

Spectrum Preventative Measures:
Spectrum chemical pretreatment system includes a dedicated chemical technician, non-chromate pretreatment system, electronic interlocking to prevent failures and strong participation from chemical supplier Test samples submitted monthly for analysis and coating weight verification Oven operation and controls to prevent under-curing.


Light Coverage

Description:

• Paint fails to fully hide the substrate surface to which it is applied
  

Causes:

• Inadequate film build
  

• Faraday cage effect
  

Spectrum Preventative Measures:
Understand customer requirements including exposed areas, unexposed areas and general expectations Apply basecoat with automated equipment on complex parts Hand spray recessed areas to ensure coverage.