Jack wrote:
On 12/8/2015 6:14 AM, J. Clarke wrote:

On 12/3/2015 9:13 PM, Mike Marlow wrote:

Hey Jack - I have a better than average clue on this stuff. I fix
this stuff. I modify the idiot designs from the factory in the
hope of reducing further decay (though there really is no fixing
rust...) but it is so easy to see how/why these problems occur,
and they all start at the factory - not in your garage.

No doubt design has a lot to do with creating rust buckets like my
GMC truck,

Not design, surface treatment. Lots of zinc in the primer and you
get a lot less rust. That's the main reason modern cars last so
long, much much improved paint.

Mike and I were not talking about surface rust, paint today does a
good job on that. The design issues are with things like the rocker
panels, quarter panels and bumpers, holding dirt and water on the
inside. My GMC rusted out in the rocker panels, same as my '55 Ford
did, from the inside out. The bumper on the GMC looked good on the
outside, other than a tiny rusty discoloration on the outside chrome.
The inside however was rusted all the way through. I think the front
bumper is in the same boat.

Correct - the consistent problem today is from rust originaqting on the
inside (from muck buildup) and eating away to the outside. Most warranties
agre against surface rust, and rust from inside is not covered.

--

-Mike-