On Tue, 21 Feb 2017 20:57:35 -0800 (PST), wrote:

On Tuesday, February 21, 2017 at 11:49:35 PM UTC-5, Clare wrote:
On Tue, 21 Feb 2017 14:09:42 -0800 (PST), wrote:

On Tuesday, February 21, 2017 at 4:44:19 PM UTC-5, Clare wrote:
On Tue, 21 Feb 2017 12:03:45 -0800 (PST), wrote:

On Thursday, February 16, 2017 at 8:42:27 AM UTC-5, Ignoramus20725 wrote:
On 2017-02-12, wrote:

Right. It's better coatings, better primers and protection, and
better application. Read, water-based coatings that often are based
on urethanes; phosphate and weldable, etching primers; galvanizing
in rust-prone areas; and electrophoresis and electrostatic
application. The first water-based coatings -- used into the '80s by
some manufacturers -- had poor adhesion and didn't weather
well. They're MUCH better now.

All of this became more necessary as body panels got thinner, with
the use of AHSS (advanced high-strength steels; a continuing
evolution of the HSLA [high-strength, low-alloy] steels that were
first used in the '70s). Rust is potentially a bigger problem than
ever because the steel is thinner.


Ed, if I buy a modern car like a Honda, how long can I realistically
expect them to last?

Jeez, that's above my pay grade, Ig. There are just too many variables. I can tell you, though, that eight years is more or less the industry benchmark these days, and when you dig into their technical literature, you'll find that ten years is a frequent target for the latest treatments.
A lot of today's vehicles have a 10 year rust "perforation" warranty.
If you get a bubble in the paint you KNOW there is perforation
allowing moisture in from the back.

Right. Those warranties generally are for perforation. The eight and ten-year terms I was talking about are for gloss -- and they aren't guarantees.

As I think I mentioned, the newer automotive paint systems are looking for gloss, usually for the clear coat, but in some cases for the base coat with no clear coat (like Ford's new system, which they aren't using for cars yet).
Even Ford's "clear coat" in the early 2000s isn't really "clear" - it
is a translucent colour coat (It's pealing a few spots on the '02
Taurus.

I'm keeping an eye on my 2004 Focus and my 2004 Sonata. So far, they're both bright and shiny, with no rust (except under the hood of the Focus, which has what looks like plain carbon steel fasteners under the hood. Stupid, to save maybe 50 cents over galvanized or stainless.)
Stainless never used under the hood - nor Galvanized We used to use
either electro-zinc or more commonlt cadmium plating - but it is
virtually impossible to do cadmium plating in North America today with
EPA rules. The choice is plain steel American bolts or Chinese
Cadmium. What would YOUR choice be???