Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Pinholes and dirt in paint problem on aluminum
Q. Our company is manufacturing alloy material and we are experiencing a problem in the coating section. Our process is pre-treatment, powder coating, liquid base coating and liquid clear coat. We experience pinholes problem after powder and liquid coating and dirt on paint after both liquid coatings. Can someone please tell me what could be the problem and give any possible solutions.
Donald BokabaAluminum alloy products painting. - Gauteng, South Africa
2006
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A. According to your description, we think that your alloy metal surface was contaminated by silicon from oil or grease. You should clean all oil by chemical liquid.
Tirger Tran- Malaysia
2006
A. If over-spray from your liquid coatings gets onto the powder before it enters the cure oven it will cause pinholes, and the dirt in the liquid coat is carried in the air and sticks to the parts. I would say that you have a breeze blowing through the paint shop.
Make every effort to calm the air as much as possible in these areas(hard to do when it gets hot) but I've experienced more quality problems from someone turning on a fan or opening a door when it's windy outside than any other reason.
Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina
2006
Q. We are a motorcycle manufacturer and so we have a liquid painting section for metal fuel tanks and plastic items of motorcycles. We are now facing pin hole problem in liquid paint line. Temperature is 28-36 °C., and humidity is about 65-75%. is there anyone to tell me the cause and solution of this problem.
Thank you
fazlul hoque
- Dhaka, Bangladesh
May 17, 2012
Dirt in curing oven contaminating solvent based paint
Q. Hello, My name is Ergan. Hope that you could help me.
I have worked in one of aluminum finishing company in Painting Department.
Currently I deal with project to reduce a defect that cause by dirt inside our paint curing oven (force convection type).
Problem : The dirt is coming from a bulk of yellowish thing near the burner. I have no idea of where does it come from. Is it possible that it comes from the burnt solvent from paint process? Or come from a side product of combustion?
thank you
plating shop employee - Jakarta
November 2, 2015
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