metal painting problem

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Last weekend, I put the finish coat of metallic aluminum paint on top of red primer on a newly fabbed metal security door, after following the directions to the letter.  Product claim was to result in a tough finish.  Much to my chagrin, I can scrape off the top coat with a gentle scratch with my fingernail.I have since tested the two paints on clean, bare metal by: 1.  applying the metallic aluminum to the bare metal          I cannot scratch this with my fingernail or thumbnail.  2.  applying the primer to the bare metal          I can, easily, scratch this off with my fingernail.  3.  applying the metallic aluminum over the primer          This top coat scratches off the primer easier than scratching the                  primer off the metal.I'm wondering if others have had similar results, and whether I'm wasting my time by using a primer, prior to top-coating.Thanks for any info.
Reply:Sounds like you've just got some really crappy primer. It wasn't dollar store primer was it?
Reply:I never have much cared for the red oxide primer.  I always go with the gray sandable primer.DewayneDixieland WeldingMM350PLincoln 100Some torchesOther misc. tools
Reply:I agree with Joe H, sounds like poor quality (or just a bad can of) primer.How long did you let the primer coat sit before you applied the top coat?     A professional car painter told me to not let the last coat of primer dry for more than a half hour before top coating.   If you let the last coat of primer dry all the way, the top coat won't adhere as well.There are no small projects
Reply:Originally Posted by Joe HSounds like you've just got some really crappy primer. It wasn't dollar store primer was it?
Reply:Originally Posted by imagineerI agree with Joe H, sounds like poor quality (or just a bad can of) primer.How long did you let the primer coat sit before you applied the top coat?     A professional car painter told me to not let the last coat of primer dry for more than a half hour before top coating.   If you let the last coat of primer dry all the way, the top coat won't adhere as well.
Reply:Originally Posted by littlefuzzI never have much cared for the red oxide primer.  I always go with the gray sandable primer.
Reply:I am assuming you are using thin wall tubing for the door.   Most thin wall stuff is very slick and shiney.  Light sanding to etch the surface would help.   What did you use to clean it?I very very rarely prime.  I brush all corner and joints with high solvent paint solution then spray. If this is an on going business, check out powder coating, then blame them for peeling finishing.
Reply:[QUOTE=tapwelder]>>>>I am assuming you are using thin wall tubing for the door.   Most thin wall stuff is very slick and shiney.  What did you use to clean it? <<<< I used angle and square tubing for the frame with expanded diamond mesh washed with detergent and rinsed at a car wash before painting.
Reply:For painted projects, I always use an epoxy primer. If the metal is clean and dry, this stuff sticks like no other. It cures by chemical reaction instead of evaporation. The only drawback is price - about double that of standard lacquer primer.Syncrowave 250 DX (Watercooled)Millermatic 251Thermal Dynamics Cutmaster 101H