[matt]

Hey Guys,

I have a question, and I am not sure if any of you have delt with a similar problem. My paint is 6 years old the car was painted and clear coated and we wet sanded it 6 years ago, it came out great. I have recently noticed very small pumps kind of like dust bumps forming in diffrent locations. I have never seen anything like this as it does not appear to be "rust blisters", but very small bumps, that are easily felt when you run your hand over them. They look like dust particles in the clear coat, but I have no idea how this is possible.

I have heard about "claying", but I am not sure if this would solve my problem. I kind of feel like I could wet sand these out, but I have never heard of having to do this 6 years after the paint was put on? Have any of you had this similar problem? What do you think it is? What do you recommend?

Thanks Mat!!

[matt]

Here is a picture of the forward fender. See the very small bumps, what are these?? How do I fix it?

Thanks for any help!!

[Adrian Worman]

Have you spoke to the body shop who did the work in the first place?
I initially thought silicone but I think that would have come thru much earlier

[dave-r]

Yeah it looks like the surface prep fell short before the paint somehow. But usually this sort of thing shows up within a year or two.

[dave-r]

Had a feeling I had seen that before somewhere and I just remembered where.

An old mate of mine from years ago had something just like that come up on his Challenger paint job. But it came up within months of it being painted.

The body had not been bare-metalled. The original paint was just rubbed down. I think it was a reaction between the new type paint and the original type that caused it. I think you can spray something on the car before the basecoat that prevents reactions like this happening. But it can still happen.

Adrian you know the Challenger this happened to. It is the red one now belonging to Philthy Phil back when this car was in South Shields. It was like that when Phil bought it. I am not sure how he fixed it. It might just have been a wet sand and polish. I don't recall him getting it re-sprayed??

But like I said. It happened within weeks or months. 6 years seems an awful long time for a reaction to start.

[matt]

Yeah the body was completly stripped to bare metal. The car was blocked and sanded several times before the final paint went on. The car was painted in 2006. I am not sure what is causing it? I am debating wet sanding them down, but I don't want to F-up my paint job. What a nightmare...

[Adrian Worman]

I'd still contact the painters for advice Matt
The red 73 car Dave?

[dave-r]

Yes that's the car Ade.

[123rmp]

I had similar bumps on my car but on the roof and and the sail panel. They showed up within a year and were getting worse and more coming up. I talked to a couple 30+ yr experience paint and body men and they confirmed exactly what I feared. When I literally dug into the problem, I saw pin-head rust on the metal under every bump....Unfortunately the issue was very small amounts of surface rust that had not gotten removed in the prep originally. My car was originally vinyl roof and the surface of the roof had gotten some damage over 40 yrs or moisture getting under it. There were rust pits scattered here and there and I sanded, wire ground, rust prevented and everything I knew to do....I thought I got it all removed or killed before paint but alas I did not.

I put a new roof on this year and am headed for a repaint soon. I posted pics before showing that earlier this year.

I bet there is rust of some kind coming thru. I know you don't want to hear that.

[Adrian Worman]

That seems to be the only obvious answer after all this time, dirt or silicone would have come up in a few months not a few years

[dave-r]

Yeah I don't think anyone wanted to mention the "R" word.

[dave-r]

Currently a topic of conversation on our club forum. Aparrantly it is common for these blisters to come up after the primer has been wet sanded. They can come up anytime but usually when it is cold and damp and sometimes they vanish when it is hot and dry. They can come up at any time after painting. Even 20 years later!

The only way to prevent it is to oven bake the primer after wet sanding. Or only dry sand the primer.

It is still OK to wet sand the top coat as moisture cannot penitrate that.