The epoxy should be applied to clean metal, not any primer (nor its sanded
residue). An excellent chromate primer
>is Stits Poly-Fiber EP-420 epoxy chromate - adheres tenaciously to
aluminum.
>Put it on my Grumman in 1977 over alodined metal; repainted her in 1987 by
>just sanding down to the green EP-420 in 1987. Not hangared. Still in
great
>shape.
>
In my experience epoxy will not adhere permanently to clean Aluminium
because corosion will creep in from the air/metal interface due to
moisture, stress corosion and maybe some other factor such as type of
alloy. Takes a year or three but does occur. I always Alodine . Epoxy won't
stick to hard anodised surfaces either.
Graham
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