PDA

View Full Version : Examples of clearcoat failure and an explanation of possible causes



Newport Viper
Dec 7th, 2008, 09:25 AM
This is from a guy over on the Viper boards. I thought I would share it here.

OK, I have a '94 with ~95K miles that stays outside 100% of the time in upstate NY since 1998. I am not complaining, nor do I care what anyone thinks about how I treat the car. It is my daily driver (which I will start to term "enjoyed daily") and I am sharing this information merely so that the current owner of my next '94 keeps it in good shape while I use this one up.

With that disclaimer out of the way, I wanted to show what happens to the clearcoat. I have a friend with a black '94 that spent the first half of it's life in a garage and most of the second half under a cover, and it is starting the same things. So I do not think it is related to sun exposure, only time.

Bubbles in the paint start when the clearcoat seems to lift off the paint layer. After they get larger you can pick at it, or the layer that has lifted off cracks and breaks away (like popping a blister.) I put the tack in the picture so you get an idea of the size.
http://gallery.viperclub.org/data/500/medium/DSCN1594.JPG

They keep getting bigger.
http://gallery.viperclub.org/data/500/medium/DSCN1589.JPG


And bigger.
http://gallery.viperclub.org/data/500/medium/DSCN1593.JPG


On the hood the paint seems to shrink and split. The white underneath might be the primer?
http://gallery.viperclub.org/data/500/medium/DSCN1599.JPG

And of course, they grow, too.
http://gallery.viperclub.org/data/500/medium/DSCN1596.JPG


On the door the lighter swirls are "in" the paint and haven't changed the surface (yet.) So while it looks odd, you cannot feel it.
http://gallery.viperclub.org/data/500/medium/DSCN1605.JPG


I don't have an explanation. The bubbles are mostly on the rear of the car, the split paint only on the hood, and the swirls only on one door.

I guess something I'd like to add....

When at the oil company, part of testing a new gasoline was to spill it on paint panels every day. Each metal plate was painted with various OEM colors and left outside 24/7. After a long time they were cleaned up to look for staining, softening of the paint, etc, etc. Never saw anything "bad" happen that wasn't repaired by the clean-up. So I have a fairly high level of respect for paints and polymers and my technical bias is towards a "good" paint applied to a "less well understood" surface. In several engineering articles it was explained that Dodge had issues with the hood and not until Amoco Chemicals helped them out did they get a material+mold+temperature that resulted in hoods that lined up with the rest of the car. One reason it cost $13,000, I guess.


Any Painters here can explain what you see on this car??????:scratchhead1

Mark Kleis
Dec 7th, 2008, 11:33 AM
Thanks for sharing that, it is a great learning tool!

I'll let Mike Phillips handle the answering of what can cause this, as he is best equipped to give the technical aspects of that answer.

roushstage2
Dec 7th, 2008, 01:11 PM
Never been too fond of Dodge paint. Mine is chipping on my Neon.

03mach1
Dec 7th, 2008, 02:15 PM
Wasn't there a couple of dodge stratus's that were having this problem too?

yalerd
Dec 7th, 2008, 02:53 PM
Very nice, thanks for documenting this and for sharing! :bigups

Candyman
Dec 7th, 2008, 03:00 PM
Yes, I thank you for sharing this as well! I have heard of it, but never actually seen a solid case of the Clear failing. And I totally agree on witing for Mr. Phillips to draw a conclusion for us on this one

For me, I would really like to see a side by side comparison with the other Viper that was apparently under cover in a garage for most of its life, and is exhibiting the same type of symptoms.

If I had to take a guess based on the pic, I would say moisture somehow got up under the clear either by possibly having a little nick in the paint, or damage from exposure which manifested itself into the state of condition we see above.

So, either Catastrophic Failure by way of moisture getting under the Cear, or since it sounds like you may have more than one documentation of similar instances to go on, which, with a little digging you might stumble upon a group of Viper's that may have had defective Primer/Sealer, or were the Prep work prior to paint was not performed correctl

It is pretty rare, but I have seen it happen every once in a while, where they just get a bad batch.

Anyway, that's my 2 cents worht. Thank you again for posting this on here!

Take it easy!

Cabdyman

Mike Phillips
Dec 8th, 2008, 08:37 AM
This is from a guy over on the Viper boards. I thought I would share it here.

OK, I have a '94 with ~95K miles that stays outside 100% of the time in upstate NY since 1998.

Any Painters here can explain what you see on this car??????:scratchhead1


I'm not a painter and don't have any technical information to add that will explain why some paints fail after 15 years of mostly outdoor exposure with little or no paint care attention except that most everything in this world trends towards breaking down, or getting worse with time especially when left unattended, not the opposite which would be things trending towards getting better and better with time when left unattended.

The only thing that seems to get better with time is wine and then when you uncork the bottle and drink it... it quits getting better.
(Because it no longer exists)

Hope I didn't let anyone down with that kind of answer but the truth is it could be something very simple like a bad paint system being used at that time on the assembly line that even with great care and attention, after 15 years the paint's going to diminish in appearance value and even fail.

:)

Michael Stoops
Dec 8th, 2008, 08:51 AM
Part of the issue is also related to the fact that the paint is from the early/mid 1990s. There seems to be a lot of paint issues stemming from that era, apparently due in part to changes in paint technology that came on line at the time.

A neighbor of ours has a '93 Ford Explorer that exhibited bizarre paint failure the included large patches of paint peeling off - not your usual clear coat failure. Even our '92 Camaro did this and the body shop we had it repainted at said they do a ton of repaints of all makes built around this time.

As for the clear coat failure in general, the main reason you can't stop it once it starts is because the failure actually happens where the clear and color coats bond. Or, in the case of clear coat failure, where they fail to bond! That means the problem starts at the bottom of the clear coat, not on the surface. You have no way of reaching down to the bottom of the clear coat to affect any sort of change, so it spreads uncontrollably. It can be brought on by UV damage, but there are other reasons for it as well.

Newport Viper
Dec 15th, 2008, 05:02 PM
Here is a follow up by another Viper Club member....interesting read.

Tom, I worked for PPG (Resins and Coatings Division, Automotive OEM and Refinish) for 16 years, starting out as a chemist and ending up in sales. That said, I'll tell you a few of the causes for the problems you showed us.

Number one: Extreme temperature variations cause delamination between the clearcoat and the basecoat color. This will also rarely happen between the basecoat color and the substrate primer. Basically the clearcoat will expand and contract at a different rate than the basecoat color in extreme heat or cold. It actually happens more often on areas of the car where snow, ice, or frost accumulate. It can also be accelerated in areas that are subsequently heated quickly, such as a hood over the engine.

Number two: Acid Rain, as previously mentioned penetrates the clearcoat surface and breaks down the chemical bond between the clearcoat and the basecoat color. Again, this will cause a delamination between the layers since once the chemical bond is destroyed, only the weaker mechanical bond remains. Like the above reason, usually occurs predominately on top surfaces for obvious reasons.

Number three: More likely on repaints...recoat sensitivity, or not enough dry time either between the basecoat color coats and the clearcoat or not enough flash time between coats of clear. Again, unlikely on OEM and will usually show up much sooner in the form of "solvent popping".

Number four: Poor compatibility between the clearcoat and the basecoat color. I would think Dodge would know better than to do this but I've seen it on OEM before. You can't just put any clear over any substrate. In the old days when I first started, guys used to try to put acrylics over laquer (yikes). The acrylics were usually much "hotter" and would dissolve the laquer under them. It can be done but usually with an intermediary barrier coat.

Number five: Insufficient clearcoat applied (or even some has been removed by color sanding or buffing) causing the clearcoat to provide a poor UV and chemical barrier. In the late 80s and early 90s the Big 3 were big offenders of this one. They were only allowed to spray a certain quantity of VOCs so rather than paint less cars, they just used less clearcoat on the same number of cars. We all remember the cars and especially trucks running around with paint peeling off back then. Well, there wasn't enough clearcoat or even colorcoat UV and chemical barrier protection to keep the primers from degrading so both the chemical and mechanical bonds were destroyed under the topcoats. It's like leaving something primered and never painting it. After a while the primer looks like chalk. This is another unlikely scenario based on the pictures you posted.

Number six: Poor waterbourne technology. Again, based on the VOC regulations of the time, auto manufacturers used a significant amount of waterbourne materials. Unfortunately, the technology was not very advanced at the time and the protection provided by these materials was substandard at best. Just about anything would penetrate these clearcoats, including water if left to absorb long enough (e.g. snow pack on the roof or hood). This scenario is also likely, based on the period your car was built.

There are a few other possible causes as well, but I could go on forever and a couple of these are most likely.

The bottom line is, the only fix is to sand it down (no chemical stripping) or media blast it off and repaint.

Good luck, hope this helps.

Mark Kleis
Dec 15th, 2008, 05:18 PM
Thanks for the update Newport Viper. Very interesting read FULL of information. I love it...

yalerd
Dec 16th, 2008, 04:20 AM
Awesome information! Thanks for sharing :bigups

Mike Phillips
Dec 16th, 2008, 06:15 AM
Here is a follow up by another Viper Club member....interesting read.

Tom, I worked for PPG (Resins and Coatings Division, Automotive OEM and Refinish) for 16 years, starting out as a chemist and ending up in sales. That said, I'll tell you a few of the causes for the problems you showed us.



Thanks for the follow-up Dave, this kind of information from an expert in this niche is invaluable and of great interest to the members of our forum.

:xyxthumbs

Tom Weed
Dec 16th, 2008, 07:02 AM
I agree, that's definitely rep points! Nice read and valuable information there.

Thank you!

roushstage2
Dec 16th, 2008, 09:27 AM
Thanks for that post! Very informative!

ColonelCash
Dec 16th, 2008, 10:04 AM
Hmm...that could explain the clear failure on my 1995 TA. In particular, the massive failure on the hood.

Mike Phillips
Dec 16th, 2008, 10:42 AM
Tagged with Clearcoat Failure Reasons and moved to Hot Topics


:)

Bert31
Dec 16th, 2008, 12:54 PM
So from reading Newport Viper's post, it sounds like the best way to avoid (or atleast put off till far in the future) clear coat failure is:

1) Wash the paint frequently (weekly if possible) and clay often (few times a year) to remove contaminents (acid rain deposits and other) in a timely fashion.

2) Take it easy when compounding paint marring out. You only have so much clear that can safely be removed. Always use least aggressive method.

3) Always keep a fresh, protective layer of LSP on your paint.

Sound right to everyone else?

Mike Phillips
Dec 16th, 2008, 02:28 PM
Sound right to everyone else?


That's a pretty good general summary list of things you can pro-actively do.

Other things would include parking under some kind of cover or in a garage whenever it's possible. When you do wash your car don't use a detergent soap.

:)

Bert31
Dec 16th, 2008, 02:47 PM
Other things would include parking under some kind of cover or in a garage whenever it's possible.


Unless that cover is a tree. Sap sitting on paint for hours while you are at work is just not a good.

Superior Shine
Dec 16th, 2008, 04:31 PM
Here is a follow up by another Viper Club member....interesting read.

Tom, I worked for PPG (Resins and Coatings Division, Automotive OEM and Refinish) for 16 years, starting out as a chemist and ending up in sales..........


So from chemist your promotion is to sales???

Is that like a pilot being "promoted" to flight attendant? :scratchhead1

Newport Viper
Dec 22nd, 2008, 04:46 PM
So from chemist your promotion is to sales???

Is that like a pilot being "promoted" to flight attendant? :scratchhead1


Sales is where it's at my friend. Your can write own check with no income ceiling. Ask me how I know. ;)