The authoritative public forum
  for Metal Finishing since 1989
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Poor adhesion in powder coatings of edges

Dear Sir,

We produce electrostatic powder coating for use with corona charging equipments. My main problem is that the powder doesn't cover at edge of the metal sheet (the cutting line). When I look to the edges I see a very slight line at the edges and I can see the metal. What can I do with this problem ?

Carlos Granados
manufacturers - Colombia
July 30, 2009

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Reading all of your post I don't think you manufacture powder. you apply powder using a corona powder gun? If so, then there are two things to establish: a) Are you using a polyester powder as some formulations tend to have excessive flow and therefore pull away from the edges. Answer Try another powder manufacturer. b) You state "pulls away from the cutting edge". If the cutting is carried out by a laser cutter then the film left behind after cutting requires being linished prior to applying powder. Also try applying a wash primer as an alternative prior to application of PC.

Terry Hickling
Birmingham, United Kingdom
July 31, 2009