The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Proper Procedure in Re-powdering Rejects in Powder Coating

Hi experts:

I am trying to understand on what is the best practice or procedure in re-painting rejected powder coated items. I have seen at one time that my supplier hang in these materials that were just buff and put them into the powdercosting line starting with the pre-treatment. I saw that the re-worked material is just like a matte finish powder coated item. I mean that the powder material is still intact in the metal. Metal is CRS by the way.

I am having doubts on what will be the reliability of the re-powdered material since the material was not scrapped to its bare metal.

Can anybody help me out so I can technically discuss this issue with my supplier? Thanks.

By the way, the reason of the reject is off color.

Thanks,

Newton Aquino
APC - Philippines
2005

---

The short story is he is doing it right. Sanded powder makes a good primer, you have to remove the gloss from the first coat of paint(giving it the matte look) so the second application will adhere properly.
If you want to return the part to bare metal, chemically stripping it is better than sanding.
The bigger issue for your supplier is the off color paint.

Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina
2005

Your on the money, I am in the sand blast metal finish bus. I do all of the blasting work for a powder coating shop. The trick is to blast the coated part with sand that has been shot and recycled several times to take the edge off the grit. Hit your part lightly holding the gun back several feet from the part as to peen the finish blow it off and shoot the new powder and bake. The old powder is your best base as it helps fill voids and pit marks like a wet paint primer does -- hope this helps out.

Ronald Mcbee
- Mccoole, Maryland, USA
2006

Another approach is to apply a coat of waterborne primer to the old powder film, allow to air-dry and then apply the new powder & bake to powder mfgr. instructions.

Terry Hickling
Birmingham, United Kingdom
2006