I have a job i did for a customer, it’s some handrails for outside a house. they are in full weather conditions. I used a zinc rich primer, and then a polyester top coat ( Black).
it’s been done for 5 months now and we are getting small pin like specks of rust showing through the powder. We sandblasted the handrails first, then applied a zinc rich primer, then the powder coat black. can anyone tell me what they think this might be?? or what i did wrong??