Rust bubble on roof

[BROADBEAN9513]

Rust Bubbles UK

Looks like something chipped the paint on the roof between the driver's side doors and now I'm getting some bubbling around the area about the size of half a penny. Haven't decided whether I'll sand and touch it up or visit my favorite body shop. View attachment 208201

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Hi ,
very interesting to hear your problem as I have areas on my roof that are bubbling but the stone chips on my bonnet are not!! I have even got Auto Express to get involved with this one in the UK as I believe that the problems on the roof are not stone chip originated but part of inclusions from the paint process. I am an inspection Engineer and have Visual qualification for welds etc. The images I have taken have shown no impact damage caused by stone chips but to me it looks like the peaks have rubbed off due to cleaning. My CX5 is just 2 years old and has 5 areas in total, some at the rear of the roof. Surely not paint chips from stones. The bonnet has stone chips showing no signs or corrosion. Mazda will not budge on this issue.

 

[madar]

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Hi ,
very interesting to hear your problem as I have areas on my roof that are bubbling but the stone chips on my bonnet are not!! I have even got Auto Express to get involved with this one in the UK as I believe that the problems on the roof are not stone chip originated but part of inclusions from the paint process. I am an inspection Engineer and have Visual qualification for welds etc. The images I have taken have shown no impact damage caused by stone chips but to me it looks like the peaks have rubbed off due to cleaning. My CX5 is just 2 years old and has 5 areas in total, some at the rear of the roof. Surely not paint chips from stones. The bonnet has stone chips showing no signs or corrosion. Mazda will not budge on this issue.

The factory rep made that clear to me that Mazda wouldn't do anything about it. Said that something could've penetrated the paint, bird crap in particular is very corrosive, hard to prove liability against Mazda.

 

[littlebear]

The factory rep made that clear to me that Mazda wouldn't do anything about it. Said that something could've penetrated the paint, bird crap in particular is very corrosive, hard to prove liability against Mazda.

I can concur that bird poop is VERY acidic and will eat paint. The clear coat on these cars is THIN as is the paint and metal. Doesn't take much to damage it.

The cars of yesteryear had THICKER clear coats, paints and sheetmetal. The EPA has killed the paints on cars and the MPG weight savings has resulted in thinner sheetmetal. It's aesthetic since sheetmetal does NOT make a car safer as the cars safety is based underneath the metal in the cage and impact beams.

 

[MikeM.]

The cars of yesteryear had THICKER clear coats, paints and sheetmetal. The EPA has killed the paints on cars and the MPG weight savings has resulted in thinner sheetmetal.

Modern automotive polyurethanes are so far superior to anything available in the 1980's it not even debatable. In the recent past it was rare for a 10 year old car to still look good unless it was garaged, waxed and pampered. Now it's common with no special precautions.

Regarding body panel thickness: Performance orientated people spend a lot of money to shed a few pounds. Who in their right mind would pay more for thicker body panels when it's just going to result in a heavier, slower pork-mobile?

 

[madar]

I can concur that bird poop is VERY acidic and will eat paint. The clear coat on these cars is THIN as is the paint and metal. Doesn't take much to damage it.

The cars of yesteryear had THICKER clear coats, paints and sheetmetal. The EPA has killed the paints on cars and the MPG weight savings has resulted in thinner sheetmetal. It's aesthetic since sheetmetal does NOT make a car safer as the cars safety is based underneath the metal in the cage and impact beams.

Bird crap has been a problem for decades. When I worked for a dealer back in the eighties the doctrine was don't wash the new vehicles on the lot, the dirt protects the paint from bird droppings. Don't know if it actually worked, but that was the thinking. Paint thickness doesn't matter, corrosive is corrosive.

 

[littlebear]

Modern automotive polyurethanes are so far superior to anything available in the 1980's it not even debatable. In the recent past it was rare for a 10 year old car to still look good unless it was garaged, waxed and pampered. Now it's common with no special precautions.

Regarding body panel thickness: Performance orientated people spend a lot of money to shed a few pounds. Who in their right mind would pay more for thicker body panels when it's just going to result in a heavier, slower pork-mobile?

Today's car paints chip a lot easier than they did years ago. It is much thinner paint and clear.

The issue with thin sheetmetal is that it dents easy and if you ever get caught in a light hailstorm it might total out the car. Older cars could handle light to mild hail storms with no problem but today's thinner roof and hood sheet metal cars dent very easily.