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Paint isn't adhering to Aluminium

I am painting some aluminium components attach to engine. I am using etch primer but till uneven paint peel-off is observed. I am doing Iron phosphating and Oven dry at 110 °C >etch primer> TSA top coat.

Paint peeloff is not observed at all parts.

Can anyone suggest solution?

Nikhil Kute
Paint tech Engg - Mumbai, India
August 12, 2010

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August 13, 2010

Hi Nikhil,

In order for iron phosphate to be successful on aluminum, the phosphating bath needs to contain fluoride. Without knowing anything else about your process, I would ask your supplier about the composition of the iron phosphate and make sure that you have a product that contains fluoride.

George Gorecki
- Naperville, Illinois

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August 16, 2010

If you mean a two pack etch primer (base and catalyst) then it has been used as a stand alone pretreatment since 1940's. Try your coating system without the iron phos... it is not needed. Note after mixing base and catalyst wait 5-10 mins before using and only mix sufficient for that day...never try to use it on the following day.

Terry Hickling
Birmingham, United Kingdom