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Aluminum Heads Paint Adhesion

#1
Getting ready to paint an LS engine. Heads are aluminum the rest of the block is iron. Is rattle can etch primer good enough prior to single stage paint? I do have SPI primer but wanted to avoid pulling out sprays guns—SPI primer good for aluminum?
 

jlcustomz

evil painter
#2
I'll never use self etch primer on aluminum again.
One big factor with coating aluminum with anything is having it as clean as possible soon before painting. Aluminum start oxidizing seconds after being perfectly cleaned which is more of a factor in high end welding.
Used to know manager of local Maaco shop. They haven't had issues on aluminum mail truck bodies with sufficient sanding ,cleaning , & very soon after coating directly with Nason 2k & ss, which we all know is far inferior to our favorite brand.
 
#3
yep, aluminum oxidizes as soon as it dries and its invisible. Etching primers will have phosphoric acid in them, which creates that white film that is so imperative to remove after using ospho, which is why its bad for aluminum.

Etching primer is mostly developed for steel. Clean and epoxy will start the adhesion process to aluminum.
 
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