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Which is a suitable process before painting [India] 

October 22, 2009

Which is a better process to do before stoving epoxy/ enamel painting - Zinc phosphating or Zinc plating- why?

Thangaraj Vagulabaranam
product designer - Chennai, TN,India

Hi, Thangaraj. Zinc phosphatizing is far more common. Zinc plating has the advantage that you have a true cathodic protection system under the paint to protect from rust in the event of a scratch or chip, but it's more expensive and probably somewhat less reliable in providing good adhesion.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Dear Sir,
You are right,
Zinc Phosphating will be best for this application.
Regards

Deep Mathpal
- Greater Noida, Uttar Pradesh, India

Dear Thangaraj,
Phosphating is the common [treatment] for before painting, if you doing the Zinc plating before painting, you will get better corrosion resistance. if, you are not having any problem in the salt spray go for phosphating

Kannan B
- Salem, Tamil Nadu, India

Hi Thangaraj

What is the material you are going to do painting, steel or cast iron etc?
Please explain your actual requirement on corrosion and adhesion for your parts.

If it is cast iron parts you can still have the choice of avoiding phosphating by replacing regular shot blasting as pretreatment process for your parts.
But make sure your corrosion and adhesion requirements are accomplished

Good luck

Vijendran Sudeendran
- Chennai, India