On Monday, February 13, 2017 at 7:54:33 PM UTC-5, Christopher Tidy wrote:
Am Sonntag, 12. Februar 2017 23:03:10 UTC+1 schrieb :

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.

Are these modern coatings two-pack paints? Or some kind of stove enamel which is baked on? I also remember hearing something about paints which contained cyanide at some point.

I'd be interested to know the composition, because they seem way better than anything I can buy.

Thanks for the replies!

Chris

I wish I could give you a simple answer, but the chemistry of automobile paints has exploded in many directions over the past ten years or so, and the chemistry is mostly over my head.

Around the world, each manufacturer seems to use something different. There are water-born systems and solvent-born systems; two-wet and three-wet systems; integrated primers and self-sealing clear coats (Nissan). It's wild out there.

Some of the primers and clear coats are catalyzed before application. I *think* the base coats are not. Some are described as melamine-based; others are described as acrylic, urethane, or polyester. Water-based systems seem to make up the majority. Again, the chemistry is beyond me.

Before I retired I was working on an in-depth study of Ford's production, but I didn't get very far. They have a new two-wet system with no clear coat ("monocoat") and it may be the leading edge. I suspect it's from Axalta.

If you want to talk to someone who specializes in this stuff, I may be able to get you some names.

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Ed Huntress