Major paint defect/lifting on factory aluminum hood.

[SayNoToPistons]

I have an on going problem with my RX-8's paint on its factory aluminum hood. Keep in mind that I do not have a garage and the hood is completely OEM including the paint (Velocity Red Mica). My RX-8 is an early build of 2004, and it is not a known issue for other RX-8's. I am aware that the aluminum layers of the hood is friction joined, and as far as I know, there is no corrosion on the alloy itself. The problem looks like it is developing from the foundation of the seems, where adhesive on the aluminum is applied prior to primer and paint. The problem does not exist on any of the steel panels of the body. The paint is perfectly fine for the aluminum doors as well, which has the same manufacturing process. Under the hood is regularly cleansed and dried every time.

This shouldn't have any relation to the Ford Flat Rock Michigan plant's known defects for the old Ford Escape and Mazda Tribute either.

From the pictures posted, you can tell where the bubbling initiates. Exactly on the adhesive of the seems underlying the hood. In some areas, the bubbling has spread to the top (exterior) of the hood. Cracks have formed, so I cleanse the area with rubbing alcohol and tried my best to fill the cracks with touch up. I hope the touch up fills the cracks within the bubbles, so water does not get in, thus not allowing it to expand and contract based on temperature changes (especially summer and winter).

Any suggestions as to what to do for a band-aide fix? I got a quote to repaint the hood along and it was quite significant given the multistage mica paint. That also means that it is unlikely to match perfectly, unless I pay to have the bumper and fenders blended as well. I am not financially ready to do that, and I certainly hope there's a way to temporarily stop the spreading for the next year or two. I have been on the search for a matching mint OEM VRM color hood for the past two months without much success.

Please excuse the dirt . It hasn't been washed for a week or so and we've had construction going on down the street. Yes, the underhood is due for a wash also!

 

[Todd@RUPES]

What a major bummer! I don't think there is much you can do to band-aid it other than sanding those areas down and trying to touch them up. The problem is under the paint (obviously) so in order to do any repair you will have to get down to the problem.

Spot sanding and adding some touch-up paint may or may not look better since that color is going to be near-impossible to touch up.

 

[Stokdgs]

Im thinking the Zinc Chromate Primer is failing or failed. Aluminium absolutely has to have only that type of Primer unless something newer and better has been invented, otherwise, moisture will cause the metal to start doing what you are seeing.
Or is this defect you see in the paint layers alone ?

Dan F

 

[SayNoToPistons]

As far as I can tell, there are no signs of the aluminum being corroded (no rust showing). I do see the primer having rather large and rough pores where the paint has cracked/bubbled.

I am afraid to sand the areas too much to reveal what's under. I'm not sure if I should sand the bubbles down (under the hood), because I am afraid the friction/abrasion from sanding to lift the paint and enlarge the cracks so much that large sections of paint will lift. What do ya'll think?

Just to clarify once again. This is the original paint and primer from factory. It has never been refinished other than the bubble that has cracked on the exterior side. I saturated the cracked bubble with rubbing alcohol, then tried my best to fill the inside of the bubble with touch up.

 

[W3bb3r04]

I have seen with a few makes having issues with metal contamination. I know that some of the fords had that happen on their hoods. You could repaint it all you wanted but the metal was contaminated and would not hold paint. Not sure if it is the same thing but just an idea.

 

[SayNoToPistons]

Just checked. The primer is actually failing, while the aluminum looks pristine with no corrosion.