What would cause aluminum to peel when painted?
What would cause aluminum to peel when painted?
(OP)
We sent out some 6063-T5 aluminum parts to be painted; the vendor called stating that aluminum (not paint) was separating and peeling back after 12 minutes @ 450 degrees. Does anyone know what would cause this?





RE: What would cause aluminum to peel when painted?
Subsurface irregularities (laps, folds, seams, fins, etc.)
RE: What would cause aluminum to peel when painted?
RE: What would cause aluminum to peel when painted?
Is the painting process a powder coat or a liquid that is then heat cured? If it's a liquid, maybe you're getting liquid into these tears and the heating process causes them to split further?
I would have a sample sectioned to look at these peals/laps/folds/etc under a metallographic microscope (any metallurgical laboratory could do this) to identify what exactly is present there.
RE: What would cause aluminum to peel when painted?
SMF1964: The paint is a liquid and then baked at 450 degrees. Unfortunately the material only lasted 12 minutes before it started to separate/peel. I requested a sample of the material for further analysis. I should receive it tomorrow. I thought that maybe there was oil or some other kind of impurity in the billet that may have caused this, not sure if there is anyway to tell. I've asked our QA to inspect the rest of the material from the lot for surface imperfections. I have never heard of aluminum extrusions separating and peeling before.
Thank you for your responses.
RE: What would cause aluminum to peel when painted?
RE: What would cause aluminum to peel when painted?
RE: What would cause aluminum to peel when painted?
RE: What would cause aluminum to peel when painted?
I'd be more inclined to say material imperfections, or corrosion from the paint are your leading cause. Is the peeling localized in a certain area? How is the extrusion oriented during the paint baking? Is the paint pooling in the areas it's peeling the base material away? Just curious.
James Spisich
Design Engineer, CSWP
RE: What would cause aluminum to peel when painted?
RE: What would cause aluminum to peel when painted?
A.R. "Andy" Nelson
Engineering Consultant
anelson@arnengineering.com