[northiam]

I noticed some tiny pin holes have formed on the roof in some areas 2 months after painting ss au. The paint been wet sanded and buffed to a good shine which was done 2 weeks after spraying and it looked fine then!
Now pin holes after 8 weeks???

[jim856229]

the clear coat drys from the inside out, how heavy did they spray each coat? how many coats? was the setup time right, and temp when sprayed in between each coat? the chemicals are still releasing if theres enuff on there you might be able to wet sand starting with 1000 grit wet/paper and working up to 2000 but id wait till the rest comes out if it started to show, there will probably be more coming nothing to do but wait

[BarryK]

It is not solvent pop if it took eight weeks to show up.
Its is a gassing starting and will get bigger as time goes on.
Here is a list of things that cause these problems on a regular bases so you can see if any apply to use.

Acid etch primers.
Lacquer primers or paints underneath.
Acid treating of metal.
Any kind of rust converter, or rust treatment or turn rust to primer or whatever this stuff is called.

Review see if any applies to you.

[pepi]

[QUOTE=BarryK]It is not solvent pop if it took eight weeks to show up.
Its is a gassing starting and will get bigger as time goes on.
Here is a list of things that cause these problems on a regular bases so you can see if any apply to use.

Acid etch primers.

quick question on this, I used this type of primer on raw sheet metal 1 years ago,. The question is will my final finish be affected by gassing out even after a year? I am starting to get the idea that some of this stuff will occur if application time and final finish are to close. Some of us apply this stuff as an intermediate finish to protect from rust and just do not have the luxury of doing a complete paint job all at once.

[BarryK]

Pepi
I'm not getting involved in this discussion about acid etch.
To answer the question maybe maybe not all depends what was put over it and how wet, primers tend to melt, epoxy most likely will not if applied over it.
Can gas first day in sun or ten years from now.

When it does a simple test is pick the biggest bubble and easily shave top off with a new razor blade, if it looks like rusted water and you blow on it you will see rusting metal underneath.

All I'm saying on the subject.

[northiam]

Doesn't make sense, these areas were bare metal, epoxied, primed in HS urethane and top coated in single stage au 2 coats.
No etch or rust converters, filler nothing
I'm thinking since it has occurred on the horizontal planes were the paint may be heavier and couldn't run or flow?

[HalfOunce]

sounds like water spots aka moisture in the air lines while coating.

[MARTINSR]

[QUOTE=pepi]

Originally Posted by BarryK

It is not solvent pop if it took eight weeks to show up.
Its is a gassing starting and will get bigger as time goes on.
Here is a list of things that cause these problems on a regular bases so you can see if any apply to use.

Acid etch primers.

quick question on this, I used this type of primer on raw sheet metal 1 years ago,. The question is will my final finish be affected by gassing out even after a year? I am starting to get the idea that some of this stuff will occur if application time and final finish are to close. Some of us apply this stuff as an intermediate finish to protect from rust and just do not have the luxury of doing a complete paint job all at once.

Water in the lines and in your finish is going to cause problems with ANY finish you apply. If you applied the etch properly, there isn't going to be an issue.

Again, there are MILLIONS upon MILLIONS of cars out there with etch primer on them, are they all going to fail? No, not if it along with the following products were applied anywhere near the tech sheets recommendations.

As we can see, acid etch had nothing what so ever to do with the original posters problem.

To address that, trapped solvents are just about all it can be. Products applied to heavy. Applying products too wet, too fast, too slow of a reducer, is still the number one cause for failure, PERIOD.

Brian

[mr4speed]

Have had this problem in the past, I associated it with wet sanding the primer. Figured it was moisture from the wet sanding that reached the pours of the metal. Stopped the wet sanding of the primers, now only dry sand and have not seen these tiny bubbles any more..........

[northiam]

Had a closer look, it appears to have no primer or epoxy, metal showing thru more like pit holes in the outer coat!!!

[Bee4Me]

Did you strip the car to bare metal?
How if you did?
What did you use to clean with?
This is starting to sound like a contamination issue early on.
Anything from a silicone airbourn to water or oil from the air system,trapped prep cleaner.
Oh boy.....

[MARTINSR]

When diagnosing a failure there are many questons that need to be asked and answered. Over the net in the few posts it is darn hard for anyone to come up with much unless it is a super common problem. None of us would have ever thought of asking "was it painted over bare metal".

Knowing this, and knowing what could also be learned about the conditions this was painted under I would say we are likely not to ever find out exactly what caused this.

As Bee4me said, this likely started early on. Spraying over cold metal likely started it. Only a little moisture in the air would have been trapped at that bare metal and it just sat there waiting to cause trouble. But again, this is a WAG at best.

Brian

[jcclark]

X2!
Well said, Brian

[boatbob2]

Hi,i have seen those pits in the paint,caused by worn rings in the compressor,oil getting past rings and filter. BUT,i have not seen the pits take 8 weeks to come out,usually it is right away.