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Non-uniformity in powder coating

Hello everybody,
we outsource our powdercoating needs, But our vendor is unable to maintain uniformity, also unable to avoid orange peel effect. even though we supply him a very good quality powder.
please help me in giving him suggestions to sort out the above said problems.

your attempt to answer will be much obliged.

Best Regards

Mallikarjun Patil
employee - INDIA
July 14, 2009

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First of three simultaneous responses --

If he knows that he has a problem and cannot fix it, I would find a suitable vendor.

James Watts
- Navarre, Florida
July 16, 2009

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Second of three simultaneous responses --

You might want to suggest to your venders that they purchase a book about powder application from the Powder Coat Institutes website (PCI).
Another route would be to have the powder manufacturers tech pay them a visit and help them with their process since they are (apparently)reluctant to do it.
Not trying to be too negative or anything like that but there are powder formulations that orange peel, nothing can be done about it (TGIC's for example).

Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina
July 16, 2009

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Third of three simultaneous responses --

This a difficult one... it is like asking a doctor to judge what is wrong with patient without a one-on-one consultation. However, as no one has come up with some ideas try these:
a)Coated items entering too quickly into a heat zone which itself is to high in temperature. This will not allow the powder to gradually go through the powder too liquid to solid phases that are necessary for good flow.
b)Too low/high film weight?
c)KV too high?
d) Varying metal mass on same article?
Is the powder OK when applied in your laboratory?

Terry Hickling
Birmingham, United Kingdom
July 20, 2009

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Thanks Mr Terry & Terry,
I found that all our vendors are using a 7 tank process for powder coating of CRCA steel & Aluminium sections. please let me know that any pretreatment process to be carried out on crca steel sheets to avoid orange peel & get good finish.

Mallikarjun Patil
- Daman, India
July 28, 2009