Slant *        6        Forum
Home Home Home
The Place to Go for Slant Six Info!
Click here to help support the Slant Six Forum upgrade!
It is currently Mon Dec 17, 2018 11:04 am

All times are UTC-08:00




Post new topic  Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Sat Aug 26, 2017 9:18 pm 
Offline
EFI Slant 6
User avatar

Joined: Mon Jan 25, 2010 11:29 pm
Posts: 482
Location: Seattle, WA
Car Model*: 75 Dart SE (2),75 Swinger, 74 Dart Sport,91 Ram RV
I have owned and seen many cars & trucks from the 70's, 80's, 90's with their white or silver topcoats peeling off from the light gray primer in sheets. Our 75 Dart's silver was like that, our 89 Dakota's white is doing it, and our 91 RAM Van's white is doing it. I've seen it happening on GM cars & trucks also. For our silver Dart, a good serious sanding & prep with several coats of PPG urethane primer before the acrylic urethane topcoat worked ok- no more peeling. The query: Does anyone know the official reason that those factory paints failed? My guesses are either too long between primer and top-coating, or just a really poor product. ???

_________________
"Louise", a 1976 Dart Custom project, (now sadly reverted to being just an "organ donor" to our other project Darts.)


Top
   
 Post subject:
PostPosted: Sat Aug 26, 2017 9:22 pm 
Offline
Supercharged

Joined: Thu May 12, 2005 11:50 pm
Posts: 5945
Location: So California
Car Model*: 64 Plymouth Valiant
I always thought it was because the EPA made them reformulate the paint.........

and it took them a long time to get good paint again....

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes
Image


Top
   
 Post subject:
PostPosted: Sun Aug 27, 2017 11:27 am 
Offline
Board Sponsor & Contributor

Joined: Thu Oct 31, 2002 5:39 pm
Posts: 23009
Location: North America
Car Model*:
No, it was not the EPA's fault, it was because the American auto industry painted the cars too quickly and too carelessly and too cheaply, with inferior/inadequate materials.

More detail:

US- and Canada-built GM and Chrysler products (especially, but also Ford) of the '70s–mid ’90s (getting much worse in the mid '80s) had the "skin disease" you describe, with paint peeling off in sheets. Mexican-built ones didn’t. ’91 and ’92 Mexican-built Dodges and Chryslers I owned had no such skin disease, but my white '92 US-built Dodge could be relieved of large chunks of paint using only a garden hose, and my dark red '91 US-built Dodge, while not quite that bad, had easily-scratched paint.

Obviously the paint processes and materials were different in countries with vs. without strong antipollution and workplace safety regulations, and that's where anti-government types' curiosity ends and they squawk about the big, bad ol' government ruining car paint for the poor, defenseless auto industry.

But that's not what really happened. It was actually the American automakers’ fault, 100 per cent. They chose to eliminate necessary body prep and paint steps and stages and use the cheapest materials, and they chose to comply with the air quality regs the cheap way instead of the right way—as they have done many, many times before with safety and pollution regs. Fact is, there were plenty of non-US-brand vehicles being built in America at that time, under the same regs, and without the shoddy paint. That proves it could be done at that time…by anyone who chose to do it.

A now-retired guy who was in the auto paint industry at the time explained it to me this way:

the issue was mostly due to the incorrect reliance on adhesion being maintained from the electrodeposition primer ( elpo ) to the topcoat without anything between. When new, no big deal, but with the thin mil thickness of topcoats, regardless of coating technology, some colors in particular were very susceptible over time to the UV rays breaking down that tenuous bond. White, light blue metallic, silvers and greys, and GM, Ford and Chrysler all were affected. My fathers ’76 Monaco in silver blew off in sheets within a few years for example. It was pure cost cutting; if there was no intermediate primer coating between the elpo and the topcoat, your paint was going to peel off. Single stage, base/clear, water- or solvent-borne, all were affected. Even on a peeling car, you'll see the flexible plastic filler panels and bumper covers held onto their paint fine, while the paint flew off the steel and aluminum panels, due to different painting processes with the plastic feeder industry that supplied the auto industry.

In the interest of completeness: shortsighted cheapness was the main reason, but wasn't the only reason why cars left factories with crummy paint, and US brands were not the only ones with problems. Mazda had issues with early-production Miatas in a particular white, for example, because they made an unwise choice of not-very-compatible paint and primer.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Image


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 3 posts ] 

All times are UTC-08:00


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited