Hello Everyone!
So, I have painted about 7 cars before. Lately I have been having an issue that I cannot quite explain. I switched to the shop line line of log products mainly because they're cheap enough. I am using the JP355 for a primer and that's been working well.

I am using the Omni plus mbx 3.5 series

For clear I'm using the JC830.

In a 6 months period 3 of the painted cars have a lot of rock chips down to the primer. So the primer is still there but the clear and base chopped off. Could it be a problem in my technique? The front end literally has a polka dot pattern because of the chipping. All 3 cars are the same. The other ones were done using The 5 star extreme clear coat and even 1.5 years later they look brand new. 5 star extreme is 4.4 box and illegal in ca. That's why I had to switch when I moved to ca

Any ideas what might be going on?

I've never used shop line but, like you said, it's cheap.
I'd guess that's the problem. Maybe try the Omni 160 clear.

sportbikepainter wrote:I've never used shop line but, like you said, it's cheap.
I'd guess that's the problem. Maybe try the Omni 160 clear.

So if the problem is in the clear, it can still take out the basecoat with it? Is that normal? I was worried it could be a basecoat adhesion problem

Pictures would help.

From what I am reading it sounds like an adhesion problem between base and primer. I don't think this is a problem the clear would create.

Could be the cheaper products, but more likely there is something missing or wrong with your process. Do some reading on bumper prep and painting. Tons of info specifically about bumpers on this site and others.

reads like adhesion to primer to me,too.
think we might need to know your process.
what grit sanding was done?
looks like Omni plus mbx 3.5 says 400 dry or 500 wet.

is it possible its just bad luck and driving condition of these cars?

i got a few friends with recent new vehicles in the past few years. a jeep and a ford truck as an example have these kind of chips on the roof metal. his all look like the base and clear was scooped away leaving primer vs. bare metal.

i got a mazda 3 a few months ago and there are lots of rocks on our highways from the big trucks and i have already caught some. my front bumper section is even worse.