Phoshate in paint ?? 3

[4059dcb]

I am not an expert on paint
can anyone let me know:
1) WHAT 'E' COAT IS ?
2) what does phosphate do to paint

the paint that I use is for outdoor metallic components

thanks Dave

 

[CoryPad]

Ecoat is an abbreviation for electrocoat. This type of coating (often epoxy based) is applied in an electrically charged bath that promotes even coverage.

Phosphate refers to a primer layer applied before paint that promotes adhesion of the paint. The actual composition of this layer is a metallic phosphate: usually zinc phosphate, but could be iron phosphate or even manganese phosphate.

If your application is outdoors, beware that epoxy-based ecoat is susceptible to damage from ultraviolet radiation. It would be best to use a UV-resistant topcoat like urethane or acrylic.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[swall]

CoryPad covered it pretty well, but I just want to mention that there are certain "reactive" primers (wash primers) that contain phosphoric acid. The acid package is mixed with the primer base and after a short dwell time the resultant primer is applied to the substrate. The phosphoric acid acts to facilitate the bond of the primer to the base metal. The use of these types of primers eliminates the need for a separate phosphate pre-treatment.